Patent Publication Number: US-2023163802-A1

Title: Antenna module having multilayer impedance converter, and electronic device comprising same

Description:
TECHNICAL FIELD 
     The present specification relates to an antenna module and an electronic device including the same. A particular implementation relates to an antenna module including a multi-layer impedance transformer, and an electronic device including the antenna module. 
     BACKGROUND ART 
     As functions of electronic devices diversify, an image display apparatus such as a multimedia player having composite functions such as playback of music or video files, games, broadcasting reception, etc. may be implemented. 
     The image display apparatus is an apparatus configured to playback image content, and receives an image from various sources and plays the image back. The image display apparatus is implemented as various devices such as a smartphone, a tablet PC, a laptop computer, a TV, etc. The image display apparatus such as a smart TV, etc. may provide an application for providing web content such as a web browser, etc. 
     A communication module including an antenna may be provided so that the electronic device such as the image display device may perform communication with a neighboring electronic device. Recently, as a display area of the image display device is enlarged, an arrangement space of the communication module including the antenna is reduced. Accordingly, there is an increasing need for arranging an antenna in a multi-layer circuit board on which the communication module is implemented. 
     A WiFi wireless interface may be considered as an interface for a communication service between electronic devices. When using such a WiFi wireless interface, a mmWave band may be used for high-speed data transmission between electronic devices. In particular, high-speed data transmission between electronic devices may be performed using a wireless interface such as an 802.11ay. 
     In relation to this, an array antenna capable of operating in a mmWave band may be mounted in the antenna module. However, electronic components such as an antenna and a transceiver circuit arranged in the antenna module are configured to be electrically connected to each other. In relation to this, electronic components arranged on different layers may be electrically connected to each other through a multi-layered transmission line, and thus, a vertical via structure may be provided. 
     In a high frequency band such as a mmWave band, there is such a problem that impedance mismatch between transmission lines and a line loss may occur significantly due to the vertical via structure. In addition, when a plurality of antennas are arranged in the multi-layer substrate, a large amount of line loss may occur according to provision of a detour path of a transmission line in order to avoid overlap between the transmission lines. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     The present disclosure is directed to solving the aforementioned problems and other drawbacks. Another aspect of the present disclosure is to provide an antenna module including a multi-layer impedance transformer operating in a millimeter wave band, and an electronic device including the same. 
     Another aspect of the present disclosure is to solve such a problem that which line loss increases due to the provision of a detour path of a plurality of feeding lines configured to feed a plurality of antenna elements constituting an array antenna in a mmWave band. 
     Another aspect of the present disclosure is to solve such a problem that impedance mismatch due to vertical vias increases through a multi-layer impedance conversion structure between an RFIC and an antenna element arranged on a PCB having a form of a multi-layer substrate. 
     Another aspect of the present disclosure is to provide a broadband feeding line structure capable of improving impedance matching characteristics of an antenna element electrically connected to a feeding line inside a PCB having a form of a multi-layer substrate. 
     Solution to Problem 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an electronic device including an antenna module. The electronic device includes: a transceiver circuit disposed in the antenna module composed of a multi-layer substrate; a first transmission line disposed on the first layer of the antenna module and configured to be electrically connected to the transceiver circuit; a second transmission line disposed on the second layer of the antenna module and configured to be electrically connected to the antenna; and a vertical via configured to vertically connect the first transmission line and the second transmission line, wherein at least one of the first and second transmission lines connected to the vertical via has an impedance transformer. 
     In an embodiment, a first impedance transformer arranged in the first transmission line connected to the vertical via may be configured to have a first width W 1  and a first length L 1 , and a second impedance transformer arranged in the second transmission line connected to the vertical via may be configured to have a second width W 2  and a second length L 2 . 
     In an embodiment, the first transmission line may include a microstrip line in which an air layer is provided without a dielectric on a conductive line arranged on a dielectric, and the second transmission line may include a strip line in which dielectrics are disposed on and below a conductive line, respectively. 
     In an embodiment, a ratio L 1 /L 2  of the first length L 1  of the first impedance transformer to the second length L 2  of the second impedance transformer may be set to be within a range from 0.45 to 1.35. 
     In an embodiment, a ratio W 2 /W 1  of the first width W 1  of the first impedance transformer to the second width W 2  of the second impedance transformer may be set to be within a range from 0.32 to 0.71. 
     In an embodiment, the first impedance transformer may be configured, in the microstrip line, to have the first width W 1  corresponding to a first impedance and the first length L 1  of a quarter wavelength that is a ¼ of a wavelength corresponding to an operating frequency, and perform impedance matching between a 50 ohm impedance of the first transmission line and a second impedance in an upper end region of the vertical via. 
     In an embodiment, the second impedance transformer may be configured, in the strip line, to have the second width W 2  corresponding to a third impedance and the second length L 2  of a quarter wavelength that is a ¼ of a wavelength corresponding to an operating frequency, and perform impedance matching between a 50 ohm impedance of the second transmission line and a fourth impedance in a lower end region of the vertical via. 
     In an embodiment, the first width W 1  of the first impedance transformer may be greater than a 50 ohm line width of the first transmission line, and the second width W 2  of the second impedance transformer may be greater than a 50 ohm line width of the second transmission line and smaller than the first width W 1 . 
     In an embodiment, the first width W 1  of the first impedance transformer may be same as a 50 ohm line width of the first transmission line, and the second width W 2  of the second impedance transformer may be different from a 50 ohm line width of the second transmission line. 
     In an embodiment, the second width W 2  of the second impedance transformer may be same as a 50 ohm line width of the second transmission line, and the first width W 1  of the first impedance transformer may be different from a 50 ohm line width of the first transmission line. 
     In an embodiment, the first transmission line may include: the first impedance transformer connected to the vertical via and has a first width W 1  and a first length L 1 , and a third impedance transformer connected to one end of the first impedance transformer and configured to have a third width W 3  and a third length L 3 , to perform impedance conversion between the first impedance transformer and the first transmission line with 50 ohm impedance. The third width W 3  may be smaller than the first width W 1  and greater than a 50 ohm line width of the first transmission line. 
     In an embodiment, the second transmission line may includes: the second impedance transformer connected to the vertical via and configured to have the second width W 2  and the second length L 2 ; and a fourth impedance transformer connected to one end of the second impedance transformer and configured to have a fourth width W 4  and a fourth length L 4 , to perform impedance conversion between the second impedance transformer and the second transmission line with 50 ohm impedance. The fourth width W 4  may be smaller than the second width W 2  and greater than a 50 ohm line width of the second transmission line. 
     In an embodiment, the antenna may be electrically connected to the second transmission line through a second vertical via. The antenna may be a lower antenna configured to radiate a signal toward a lower direction of the antenna module. 
     In an embodiment, the vertical via may include a plurality of via pads and a plurality of vertical connection parts to vertically connect the microstrip line arranged on an uppermost layer of the multi-layer substrate to the strip line arranged in the multi-layer substrate. The plurality of via pads, arranged on different layers, are disposed on same layers as layers of grounds to have gaps with a certain width between the plurality of via pads and the grounds, respectively. 
     In an embodiment, the plurality of via pads, arranged on different layers, may be disposed on same layers as layers of grounds to have gaps with certain different widths between the plurality of via pads and the grounds, respectively. At least one of the first impedance transformer and the second impedance transformer may be implemented to have a line width of 50 ohms. 
     In an embodiment, the antenna modules may further include: the lower antenna; a side antenna arranged inside the multi-layer substrate and configured to radiate a signal toward a side direction of the multi-layer substrate; and a ground via wall arranged at a further inner position in the multi-layer substrate compared to the side antenna, and configured to vertically connect different ground layers to each other. 
     In an embodiment, the ground via wall may be arranged at a further inner position in the multi-layer substrate compared to the side antenna to improve directivity, toward a side direction, of a signal radiated by the side antenna. 
     In an embodiment, the antenna module may include a first antenna and a second antenna arranged further apart from the transceiver circuit compared to the first antenna. The transceiver circuit may be connected to the first antenna through a first microstrip line and a first strip line, and connected to the second antenna through a second microstrip line and a second strip line. A length of the second microstrip line may be greater than a length of the first microstrip line to compensate for a difference between a length from the transceiver circuit to the first antenna and a length from the transceiver circuit to the second antenna. 
     According to another aspect of the present specification, there is also provided an antenna module including: a first transmission line disposed on a first layer of the antenna module and configured to be electrically connected to a transceiver circuit; a second transmission line disposed on a second layer of the antenna module and configured to be electrically connected to an antenna; and a vertical via configured to vertically connect the first transmission line and the second transmission line. 
     In an embodiment, a first impedance transformer, arranged in the first transmission line connected to the vertical via, may be configured to have a first width W 1  and a first length L 1 , and a second impedance transformer, arranged in the second transmission line connected to the vertical via, may be configured to have a second width W 2  and a second length L 2 . 
     In an embodiment, the first transmission line may include a microstrip line in which an air layer is provided without a dielectric on a conductive line arranged on a dielectric, and the second transmission line may include a strip line in which dielectrics are disposed on and below a conductive line, respectively. 
     In an embodiment, a ratio L 1 /L 2  of the first length L 1  of the first impedance transformer to the second length L 2  of the second impedance transformer may be set to be within a range from 0.45 to 1.35. 
     In an embodiment, a ratio W 2 /W 1  of the first width W 1  of the first impedance transformer to the second width W 2  of the second impedance transformer may be set to be within a range from 0.32 to 0.71. 
     Advantageous Effects of Invention 
     Technical effects of the antenna module having the multi-layer impedance conversion structure operating in a millimeter wave band and the electronic device including the same are described below. 
     According to an embodiment, an antenna module in which all feeding lines may be arranged using a small number of layers in a space in which it is difficult to arrange all the feeding lines may be provided. 
     According to an embodiment, a feeding line may be connected, along minimized detour paths, to all antennas in the mmWave antenna module having an extended coverage to thereby minimize a line loss. 
     According to an embodiment, both performance of a transmission loss S 11  and performance of a transmission loss S 21  may be enhanced through impedance matching of feeding lines in a broadband of the millimeter wave band. 
     According to an embodiment, impedance matching characteristics of an antenna element electrically connected to a feeding line inside a multi-layered board type PCB may be enhanced by configuring different types of impedance transformers with reference to vertical vias. 
     According to an embodiment, transmission lines including a microstrip line and a strip line are connected to each other via a vertical via and an impedance transformer is provided on at least one side to thereby minimize a line loss while performing impedance matching. 
     According to an embodiment, by adjusting a gap interval between a vertical via and an adjacent ground, the vertical via connecting transmission lines on different layers to each other, a line loss may be minimized while impedance matching is performed. 
     Further scope of applicability of the present disclosure will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, such as the preferred embodiment of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram schematically illustrating an example of a whole pf a wireless audiovisual (AV) system including an image display device according to an embodiment of the present specification. 
         FIG.  2    illustrates a detailed configuration of electronic devices configured to support a wireless interface according to the present specification. 
         FIG.  3 A  illustrates a request to send frame (RTS) and a clear to send (CTS) frame according to the present specification. 
         FIG.  3 B  illustrates a block diagram of a communication system  400  according to an example of the present specification. 
         FIG.  4    illustrates an electronic device in which a plurality of antenna modules and a plurality of transceiver circuits are arranged, according to an embodiment. 
         FIG.  5 A  illustrates a configuration in which a multi-layer circuit substrate in which an array antenna module is arranged is connected to a radio frequency integrated chip (RFIC), in relation to the present specification. 
         FIG.  5 B  is a conceptual diagram illustrating antenna structures having different radiation directions. 
         FIG.  5 C  illustrates a combination structure between a multi-layer substrate and a main substrate according to embodiments. 
         FIG.  6    is a conceptual diagram illustrating a plurality of communication modules arranged in a lower portion of the image display device  100 , and communication between the communication modules and other communication modules arranged in a front direction from the image display device. 
         FIGS.  7 A and  7 B  illustrate a comparison between arrangement structures of a radio frequency (RF) line and a power line in a configuration in which RFICs corresponding to transceiver circuits are connected to different antennas. 
         FIG.  8    illustrates a configuration of an antenna module including a multi-layer substrate according to the present specification. 
         FIG.  9    illustrates an impedance matching structure having a vertical via connection between the transmission lines connecting the RFIC to the antenna disclosed in the present specification. 
         FIG.  10 A  illustrates reflection coefficient characteristics for each frequency according to a ratio L 1 /L 2  between lengths of first and second impedance transformers. In addition,  FIG.  10 B  illustrates reflection coefficient characteristics for each frequency according to a ratio W 1 /VV 2  between widths of the first and second impedance transformers. 
         FIG.  11    illustrates an equivalent circuit of an impedance conversion structure proposed in the present specification to solve a problem described above. 
         FIGS.  12 A to  12 C  illustrate transmission line structures connected through via holes, respectively, according to various embodiments. 
         FIG.  13 A  illustrates a configuration of impedance-conversion is performed via a plurality of impedance transformers in a case of connection of a microstrip line to a vertical via. 
         FIG.  13 B  illustrate a configuration of impedance-conversion is performed via a plurality of impedance transformers in a case of connection of a strip line to a vertical via. 
         FIG.  14 A  illustrates a multi-layered conversion structure in which a vertical via is arranged in each layer to be apart from a ground layer by a same distance. 
         FIG.  14 B  illustrates a multi-layered conversion structure in which a vertical via is arranged on each layer to be apart from a ground layer by a different distance. 
         FIG.  15 A  illustrates impedance changes in a first structure and a second structure on a Smith chart, the first structure including feeding lines connected to each other through a vertical via and the second structure including a multi-layer impedance transformer.  FIG.  15 B  illustrates a reflection loss and a transmission loss according to frequency changes in the first and second structures of  FIG.  15 A . 
         FIG.  16 A  illustrates a configuration in which a plurality of ports of the RFIC are connected to the plurality of antenna devices.  FIG.  16 B  is a side view illustrating the RFIC connected to the plurality of antenna devices on a multi-layer substrate. 
         FIG.  17 A  illustrates a structure in which an antenna module  1100  including a first type antenna and a second type antenna both provided as an array antenna is arranged in an electronic device  1000 .  FIG.  17 B  is a magnified view of a plurality of array antenna modules. 
         FIG.  18    illustrates antenna modules combined to have different combination structures at a particular position in the electronic device. 
     
    
    
     MODE FOR THE INVENTION 
     Description will now be given in detail according to exemplary embodiments disclosed herein, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components may be provided with the same or similar reference numbers, and description thereof will not be repeated. In general, a suffix such as “module” and “unit” may be used to refer to elements or components. Use of such a suffix herein is merely intended to facilitate description of the specification, and the suffix itself is not intended to give any special meaning or function. In describing the present disclosure, if a detailed explanation for a related known function or construction is considered to unnecessarily divert the gist of the present disclosure, such explanation has been omitted but would be understood by those skilled in the art. The accompanying drawings are used to help easily understand the technical idea of the present disclosure and it should be understood that the idea of the present disclosure is not limited by the accompanying drawings. The idea of the present disclosure should be construed to extend to any alterations, equivalents and substitutes besides the accompanying drawings. 
     It will be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another. 
     It will be understood that when an element is referred to as being “connected with” another element, the element can be connected with the another element or intervening elements may also be present. In contrast, when an element is referred to as being “directly connected with” another element, there are no intervening elements present. 
     A singular representation may include a plural representation unless it represents a definitely different meaning from the context. 
     Terms such as “include” or “has” are used herein and should be understood that they are intended to indicate an existence of several components, functions or steps, disclosed in the specification, and it is also understood that greater or fewer components, functions, or steps may likewise be utilized. 
     Electronic devices presented herein may be implemented using a variety of different types of terminals. Examples of such devices include cellular phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigators, slate PCs, tablet PCs, ultra books, wearable devices (for example, smart watches, smart glasses, head mounted displays (HMDs)), and the like. 
     By way of non-limiting example only, further description will be made with reference to particular types of mobile terminals. However, such teachings apply equally to other types of terminals, such as those types noted above. In addition, these teachings may also be applied to stationary terminals such as digital TV, desktop computers, digital signages, and the like. 
       FIG.  1    is a diagram schematically illustrating an example of a whole pf a wireless audiovisual (AV) system including an image display device according to an embodiment of the present specification. 
     As illustrated in  FIG.  1   , the image display device  100  according to another embodiment of the present disclosure is connected to the wireless AV system (or a broadcasting network) and an Internet network. The image display device  100  may be, for example, a network TV, a smart TV, a hybrid broadcast broadband TV (HBBTV), or the like. 
     The image display device  100  may be wirelessly connected to the wireless AV system (or the broadcasting network) via a wireless interface or wirelessly or wiredly connected to the Internet network via an Internet interface. In relation to this, the image display device  100  may be configured to be connected to a server or another electronic device via a wireless communication system. As an example, the image display device  100  needs to provide an  802 . 11 ay communication service operating in a millimeter wave (mmWave) band to transmit or receive large-capacity data at a high speed. 
     The mmWave band may be any frequency band in a range of 10 GHz to 300 GHz. In this specification, the mmWave band may include an 802.11 ay band of a 60 GHz band. In addition, the mmWave band may include a 5G frequency band of a 28 GHz band or the 802.1ay band of the 60 GHz band. The 5G frequency band may be set to about 24 to 43 GHz band and the 802.11ay band may be set to 57 to 70 GHz or 57 to 63 GHz band, but are not limited thereto. 
     The image display device  100  may wirelessly transmit or receive data to/from an electronic device in a periphery of the image display device  100 , e.g., a set-top box or another electronic device, via the wireless interface. As an example, the image display device  100  may transmit or receive wireless AV data to/from a set-top box or another electronic device, e.g., a mobile terminal arranged in front of or below the image display device. 
     The image display device  100  includes, for example, a wireless interface  101   b , a section filter  102   b , an application information table (AIT) filter  103   b , an application data processing unit  104   b , a data processing unit  111   b , a media player  106   b , an Internet protocol processing unit  107   b , an Internet interface  108   b , and a runtime module  109   b.    
     Through a broadcast interface that is the wireless interface  101   b , AIT data, real-time broadcast content, application data, and a stream event are received. The real-time broadcast content may be referred to as linear audio/video (AN) content. 
     The section filter  102   b  performs section filtering on four types of data received through the wireless interface  101   b  to transmit the AIT data to the AIT filter  103   b , the linear AN content to the data processing unit  111   b , and the stream events and the application data to the application data processing unit  104   b.    
     Non-linear AN content and the application data are received through the Internet interface  108   b . The non-linear AN content may be, for example, a content on demand (COD) application. The non-linear AN content is transmitted to the media player  106   b , and the application data is transmitted to the runtime module  109   b.    
     Further, the runtime module  109   b  includes, for example, an application manager and a browser as illustrated in  FIG.  1   . The application manager controls a life cycle of an interactive application using, for example, the AIT data. In addition, the browser performs, for example, a function of displaying and processing the interactive application. 
     Hereinafter, a communication module having an antenna for providing a wireless interface in an electronic device such as the above-described image display device is described in detail. In relation to this, the wireless interface for communication between electronic devices may be a WiFi wireless interface, but is not limited thereto. As an example, a wireless interface supporting the 802.11ay standard may be provided for high-speed data transmission between electronic devices. 
     The 802.11ay standard is a successor standard for raising a throughput for the 802.11ad standard to 20 Gbps or greater. An electronic device supporting an 802.11ay wireless interface may be configured to use a frequency band of about 57 to 64 GHz. The 802.11ay wireless interface may be configured to provide backward compatibility for an 802.11ad wireless interface. The electronic device providing the 802.11ay wireless interface may be configured to provide coexistence with a legacy device using the same band. 
     In relation to a wireless environment for the  802 . 11 ay standard, it may be configured to provide a coverage of 10 meters or longer in an indoor environment, and 100 meters or longer in an outdoor environment with a line of sight (LOS) channel condition. 
     The electronic device supporting the 802.11ay wireless interface may be configured to provide visual reality (VR) headset connectivity, support server backups, and support cloud applications that require low latency. 
     An ultra short range (USR) communication scenario, i.e., a near field communication scenario which is a use case of the 802.11ay wireless interface, is a model for fast large-capacity data exchange between two terminals. The USR communication scenario may be configured to require low power consumption of less than 400 mW, while providing a fast link setup within 100 msec, transaction time within 1 second, and a 10 Gbps data rate at a very close distance of less than 10 cm. 
     As the use case of the 802.11ay wireless interface, the 8K UHD Wireless Transfer at Smart Home Usage Model may be taken into account. In the Smart Home Usage Model, a wireless interface between a source device and a sync device may be taken into consideration to stream 8K UHD content at home. In relation to this, the source device may be one of a set-top box, a Blue-ray player, a tablet PC, and a smart phone and the sink device may be one of a smart TV and a display device, but are not limited thereto. In relation to this, the wireless interface may be configured to transmit uncompressed 8K UHD streaming (60 fps, 24 bits per pixel, at least 4:2:2) with a coverage of less than 5 m between the source device and the sink device. To do so, the wireless interface may be configured such that data is transmitted between electronic devices at a speed of at least 28 Gbps. 
     In order to provide such a wireless interface, embodiments related to an array antenna operating in a mmWave band and an electronic device including the same is described with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. 
       FIG.  2    illustrates a detailed configuration of electronic devices configured to support a wireless interface according to the present specification.  FIG.  2    illustrates a block diagram of an access point  110  (generally, a first wireless node) and an access terminal  120  (generally, a second wireless node) in a wireless communication system. The access point  110  is a transmitting entity for a downlink and a receiving entity for an uplink. The access terminal  120  is a transmitting entity for an uplink and a receiving entity for a downlink. As used herein, a “transmitting entity” is an independently operating apparatus or device capable of transmitting data through a wireless channel, and a “receiving entity” is an independently operating apparatus or device capable of receiving data through a wireless channel. 
     Referring to  FIGS.  1  and  2   , a set-top box (STB) of  FIG.  1    may be the access point  110 , and an electronic device, that is, the image display device  100  of  FIG.  1    may be the access terminal  120 , but are not limited thereto. Accordingly, it should be understood that the access point  110  may alternatively be an access terminal, and the access terminal  120  may alternatively be an access point. 
     To transmit data, the access point  110  includes a transmission (TX) data processor  220 , a frame builder  222 , a TX processor  224 , a plurality of transceivers  226 - 1  to  226 -N, and a plurality of antennas  230 - 1  to  230 -N. The access point  110  also includes a controller  234  configured to control operations of the access point  110 . 
     To transmit data, the access point  110  includes a TX data processor  220 , a frame builder  222 , a TX processor  224 , a plurality of transceivers  226 - 1  to  226 -N, and a plurality of antennas  230 - 1  to  230 -N. The access point  110  also includes a controller  234  configured to control operations of the access point  110 . 
     During operation, the TX data processor  220  receives data (e.g., data bits) from a data source  215 , and processes the data for transmission. For example, the TX data processor  220  may encode data (e.g., data bits) into encoded data, and modulate the encoded data into data symbols. The TX data processor  220  may support different modulation and coding schemes (MCSs). For example, the TX data processor  220  may encode data at any one of a plurality of different coding rates (e.g., using low-density parity check (LDPC) encoding). In addition, the TX data processor  220  may modulate the encoded data using any one of a plurality of different modulation schemes including, but not limited to, BPSK, QPSK, 16QAM, 64QAM, 64APSK, 128APSK, 256QAM, and 256APSK. 
     The controller  234  may transmit, to the TX data processor  220 , a command for specifying an MCS to be used (e.g., based on channel conditions for a downlink). The TX data processor  220  may encode and modulate the data received from the data source  215  according to the specified MCS. It needs to be recognized that the TX data processor  220  may perform additional processing on the data, such as data scrambling and/or other processing. The TX data processor  220  outputs the data symbols to the frame builder  222 . 
     The frame builder  222  constructs a frame (also referred to as a packet) and inserts the data symbols into a data payload of the frame. The frame may include a preamble, a header, and a data payload. The preamble may include a short training field (STF) sequence and a channel estimation (CE) sequence to assist the access terminal  120  in receiving the frame. The header may include information regarding data in a payload, such as a length of the data and an MCS used to encode and modulate the data. Based on this information, the access terminal  120  may demodulate and decode the data. The data in the payload may be partitioned among a plurality of blocks, and each block may contain a part of the data and a guard interval (GI) to assist the receiver in phase tracking. The frame builder  222  outputs the frame to the TX processor  224 . 
     The TX processor  224  processes the frame for transmission on a downlink. For example, the TX processor  224  may support different transmission modes, e.g., an orthogonal frequency-division multiplexing (OFDM) transmission mode and a single-carrier (SC) transmission mode. In this example, the controller  234  may transmit, to the TX processor  224 , a command for specifying a transmission mode to be used, and the TX processor  224  may process the frame for transmission according to the specified transmission mode. The TX processor  224  may apply a spectrum mask to the frame so that a frequency configuration of a downlink signal complies with particular spectrum requirements. 
     The TX processor  224  may support multiple-input-multiple-output (MIMO) transmission. In these aspects, the access point  110  may include a plurality of antennas  230 - 1  to  230 -N and a plurality of transceivers  226 - 1  to  226 -N (e.g., one for each antenna). The TX processor  224  may perform spatial processing on incoming frames and provide a plurality of transmission frame streams to a plurality of antennas. The transceivers  226 - 1  to  226 -N receive and process (e.g., convert to analog, amplify, filter, and frequency up-convert) each of the transmission frame streams to generate transmission signals for transmission through the antennas  230 - 1  to  230 -N. 
     To transmit data, the access terminal  120  includes a TX data processor  260 , a frame builder  262 , a TX processor  264 , a plurality of transceivers  266 - 1  to  266 -M, and a plurality of antennas  270 - 1  to  270 -M (e.g., one antenna per transceiver). The access terminal  120  may transmit data to the access point  110  on an uplink and/or transmit the data to another access terminal (e.g., for peer-to-peer communication). The access terminal  120  also includes a controller  274  configured to control operations of the access terminal  120 . 
     The transceivers  266 - 1  to  266 -M receive and process (e.g., convert to analog, amplify, filter, and frequency up-convert) an output from the TX processor  264  for transmission via one or more of the antennas  270 - 1  to  270 -M. For example, a transceiver  266 - 1  may up-convert the output from the TX processor  264  into a transmission signal having a frequency in a 60 GHz band. Accordingly, the antenna module described herein may be configured to perform a beamforming operation in the 60 GHz band, for example, in a band of about 57 to 63 GHz. In addition, the antenna module may be configured to support MIMO transmission while performing beamforming in the 60 GHz band. 
     In relation to this, the antennas  270 - 1  to  270 -M and the transceivers  266 - 1  to  266 -M may be implemented in an integrated form on a multi-layer circuit board. To do so, among the antennas  270 - 1  to  270 -M, an antenna configured to operate with vertical polarization may be vertically arranged inside the multi-layer circuit board. 
     To receive data, the access point  110  includes a reception (RX) processor  242  and an RX data processor  244 . During operation, the transceivers  226 - 1  to  226 -N receive a signal (e.g., from the access terminal  120 ) and spatially process (e.g., frequency down-convert, amplify, filter, and digitally convert) the received signal. 
     The RX processor  242  receives outputs from the transceivers  226 - 1  through  226 -N and processes the outputs to recover data symbols. For example, the access point  110  may receive data from a frame (e.g., from the access terminal  120 ). In this example, the RX processor  242  may detect a start of the frame using a short training field (STF) sequence in a preamble of the frame. The RX processor  242  may also use the STF for automatic gain control (AGC) adjustment. The RX processor  242  may also perform channel estimation (e.g., using a channel estimation (CE) sequence in the preamble of the frame), and perform channel equalization on the received signal based on the channel estimation. 
     The RX data processor  244  receives data symbols from the RX processor  242  and an indication of a corresponding MSC scheme from the controller  234 . The RX data processor  244  demodulates and decodes the data symbols, recovers the data according to the indicated MSC scheme, stores the recovered data (e.g., data bits), and/or outputs the recovered data to a data sink  246  for additional processing. 
     The access terminal  120  may transmit the data using an orthogonal frequency-division multiplexing (OFDM) transmission mode or an single-carrier (SC) transmission mode. In this case, the RX processor  242  may process the received signal according to a selected transmission mode. In addition, as described above, the TX processor  264  may support MIMO transmission. In this case, the access point  110  includes the antennas  230 - 1  to  230 -N and the transceivers  226 - 1  to  226 -N (e.g., one for each antenna). Accordingly, the antenna module described herein may be configured to perform a beamforming operation in the 60 GHz band, for example, in a band of about 57 to 63 GHz. In addition, the antenna module may be configured to support MIMO transmission while performing beamforming in the 60 GHz band. 
     In relation to this, the antennas  230 - 1  to  230 -M and the transceivers  226 - 1  to  226 -M may be implemented in an integrated form on the multi-layer circuit board. To do so, among the antennas  230 - 1  to  230 -M, an antenna configured to operate with vertical polarization may be vertically arranged inside the multi-layer circuit board. 
     Meanwhile, each transceiver receives and processes (e.g., frequency down-converts, amplifies, filters, and digitally converts) a signal from each antenna. The RX processor  242  may perform spatial processing on the outputs from the transceivers  226 - 1  to  226 -N to recover the data symbols. 
     The access point  110  also includes a memory  236  coupled to the controller  234 . The memory  236  may store commands that, when executed by the controller  234 , cause the controller  234  to perform one or more of the operations described herein. Similarly, the access terminal  120  also includes a memory  276  coupled to the controller  274 . The memory  276  may store commands that, when executed by the controller  274 , cause the controller  274  to perform one or more of the operations described herein. 
     The electronic device supporting the  802 . 11 ay wireless interface described herein determines whether a communication medium may be used to communicate with another electronic device. To do so, the electronic device transmits a request to send (RTS)-TRN frame including an RTS part and a first beam training sequence. In relation to this,  FIG.  3 A  illustrates an RTS frame and a clear to send (CTS) frame according to the present specification. In relation to this, a transmission device may use the RTA frame to determine whether a communication medium may be used to transmit one or more data frames to a destination device. In a response to receiving the RTS frame, the destination device transmits the CTS frame back to the transmission device when the communication medium may be used. In a response to receiving the CTS frame, the transmission device transmits one or more data frames to the destination device. In a response to successfully receiving the one or more data frames, the destination device transmits one or more acknowledgment (“ACK”) frames to the transmission device. 
     Referring to (a) of  FIG.  3 A , a frame  300  includes the RTS part including a frame control field  310 , a duration field  312 , a receiver address field  314 , a transmitter address field  316 , and a frame check sequence field  318 . To improve communication and reduce interference, the frame  300  further includes a beam training sequence field  320  for configuring respective antennas of the destination device and one or more neighboring devices. 
     Referring to (b) of  FIG.  3 A , a CTS frame  350  includes an CTS part containing a frame control field  360 , a duration field  362 , a receiver address field  364 , and a frame check sequence field  366 . To improve communication and reduce interference, a frame, i.e., is the CTS frame  350  further includes a beam training sequence field  368  for configuring respective antennas of the destination device and one or more neighboring devices. 
     The beam training sequence fields  320  and  368  may conform to a training (TRN) sequence according to the IEEE  802 . 11 ad or  802 . 11 ay standard. The transmission device may use the beam training sequence field  368  to configure an antenna of the transmission device for directional transmission to the destination device. The transmission device may use the beam training sequence field to configure respective antennas of the transmission and destination devices to prevent transmission interference at the destination device. In this case, the beam training sequence field may be used to configure respective antennas of the transmission and destination devices to generate an antenna radiation pattern with nulls targeting the destination device. 
     Accordingly, electronic devices supporting the 802.11ay wireless interface may provide an initial beam to have a low interference level with each other, using a beamforming pattern determined according to a beam training sequence. In relation to this,  FIG.  3 B  illustrates a block diagram of a communication system  400  according to an example of the present specification. As illustrated in  FIG.  3 B , the first and second devices  410  and  420  may improve communication performance by matching directions of main beams with each other. To reduce interference with a third device  430 , the first and second devices  410  and  420  may provide a signal-null having a weak signal strength in a specific direction. 
     In relation to the provision of the main beams and the signal-null, a plurality of electronic devices described herein may be configured to perform beamforming through an array antenna. Referring to  FIG.  3 B , some of the electronic devices may be configured to communicate with an array antenna of another electronic device through a single antenna. In relation to this, when communicating through a single antenna, a beam pattern is provided as an omnidirectional pattern. 
       FIG.  3 B  illustrates that the first to third devices  410  to  430  perform beamforming and a fourth device  440  does not perform beamforming. However, performance of beamforming is not limited thereto. Accordingly, three of the first to fourth devices  410  All  440  may be configured to perform beamforming, and the other may be configured not to perform beamforming. 
     As another example, only one of the first to fourth devices  410  may be configured to perform beamforming, and the other three devices may be configured not to perform beamforming. As another example, two of the first to fourth devices  410  may be configured to perform beamforming but the other two may be configured not to perform beamforming. As another example, all of the first to fourth devices  410  may be configured to perform beamforming. 
     Referring to  FIGS.  3 A and  3 B , the first device  410  determines that the first device  410  is an intended receiving device for the CTS-TRN frame  350 , i.e., the CTS frame, based on an address indicated in the receiver address field  364  of the CTS-TRN frame  350 . In response to the determining as being the intended receiving device for the CTS-TRN frame  350 , the first device  410  may selectively use a beam training sequence in the beam training sequence field  368  of the CTS-TRN frame  350  received to configure an antenna of the first device  410  for directional transmission substantially targeting the second device  420 . That is, the antenna of the first device  410  is configured to generate an antenna radiation pattern having a primary lobe (e.g., a highest gain lobe) substantially targeting the second device  420  and non-primary lobes targeting other directions. 
     The second device  420  is already aware of a direction toward the first device  410  on a basis of the beam training sequence of the beam training sequence field  320  in the frame  300 , i.e., an RTS-TRN frame previously received by the second device  420 . Thus, the second device  420  may configure an antenna of the second device  420  for directional reception selectively targeting the first device  410  (e.g., a primary antenna radiation lobe). Therefore, while the antenna of the first device  410  is configured for the directional transmission to the second device  420  and the antenna of the second device  420  is configured for the directional reception from the first device  410 , the first device  410  transmits one or more data frames to the second device  420 . Accordingly, the first and second devices  410  and  420  perform directional transmission/reception DIR-TX/RX of one or more data frames through the primary lobe (the main beam). 
     The first and second devices  410  and  420  may partially modify a beam cdue to an antenna radiation pattern having non-primary lobes. 
     In relation to this, the third device  430  determines that the third device  430  is not the intended receiving device for the CTS-TRN frame  350  on a basis of an address indicated in the receiver address field  364  of the CTS-TRN frame  350 . In a response to the determining that third device  430  is not the intended receiving device for the CTS-TRN frame  350 , the third device  430  uses the beam training sequence in the beam training sequence field  368  of the received CTS-TRN  350  and a sequence of the beam training sequence field  320  in the RTS-TRN frame  300  previously received, to configure the antenna of the third device  430  to generate antenna radiation patterns having nulls substantially targeting the second device  420  and the first device  410 , respectively. The nulls may be based on an estimated angle of arrival of the RTS-TRN frame  300  previously received, and the CTS-TRN frame  350 . In general, the third device  430  generates antenna radiation patterns having desired signal powers, rejections or gains targeting the first device  410  and the second device  420 , respectively (for example, to achieve an estimated interference in the first and second devices  410  and  420  to be equal to or less than a defined threshold (e.g., to acquire desired BER, SNR, SINR and/or other one or more communication properties)). 
     The third device  430  may configure an antenna transmission radiation pattern of the third device  430  by estimating antenna gains in directions toward the first and second devices  410  and  420 , estimating antenna reciprocity differences between the third device  430  and the first and second devices  410  and  420  (e.g., a transmission antenna gain minus a reception antenna gain), and respectively calculating the antenna gains and the antenna reciprocity differences throughout one or more sectors to determine estimated interferences corresponding to the first and second devices  410  and  420 . 
     The third device  430  transmits the RTS-TRN frame  300  intended for the fourth device  440  and to be received by the fourth device  440 . As long as the first and second devices  410  and  420  perform communication on a basis of durations indicated in the duration fields  312  and  362  of the RTS-TRN frame  300  and the CTS-TRN frame  350 , respectively, the third device  430  maintains an antenna configuration having nulls intended for the first and second devices  410  and  420 . Since the antenna of the third device  430  is configured to generate nulls targeting the first device  410  and the second device  420 , transmission of the RTS-TRN frame  300  by the third device  430  may generate reduced interference in the first device  410  and the second device  420 , respectively. 
     Accordingly, the electronic devices supporting the 802.11ay wireless interface disclosed herein may provide a signal null direction in a specific direction to reduce interference while matching main beam directions with each other using an array antenna. To do so, a plurality of the electronic devices may provide an initial beam direction through a beam training sequence and change a beam direction through a periodically updated beam training sequence. 
     As described above, for high-speed data communication between the electronic devices, beam directions should be configured to match each other. In addition, a loss of a radio signal transmitted to an antenna element needs to be minimized for high-speed data communication. To do so, an array antenna needs to be arranged in a multi-layer substrate on which a radio frequency integrated chip (RFIC) is arranged. In addition, for radiation efficiency, the array antenna needs to be arranged adjacent to a side region in the multi-layer substrate. 
     In addition, in order to adapt to a change in a wireless environment, a beam training sequence between the electronic devices needs to be updated. To update the beam training sequence, the RFIC needs to periodically transceive signals with a processor such as a modem. Therefore, to minimize update delay time, transception of a control signal between the RFIC and the modem needs to be performed within short time. To do so, a physical length of a connection path between the RFIC and the modem needs to be reduced. To do so, the modem may be arranged on a multi-layer substrate on which the array antenna and the RFIC are arranged. Alternatively, in a structure in which the array antenna and the RFIC are arranged on the multi-layer substrate and the modem is arranged on a main substrate, a connection length between the RFIC and the modem may be configured to be minimized. In relation to this, a detailed structure is described with reference to  FIG.  5 C . 
     Hereinafter, an electronic device having an antenna operable in a mmWave band will be described. In relation to this,  FIG.  4    illustrates an electronic device in which a plurality of antenna modules and a plurality of transceiver circuits are arranged. Referring to  FIG.  4   , a home appliance in which the antenna modules and the transceiver circuit modules are arranged may be a television, but is not limited thereto. Accordingly, in the present specification, the home appliance in which the antenna modules and the transceiver circuit modules are arranged may include any home appliance or a display device configured to support a communication service in a millimeter wave band. 
     Referring to  FIG.  4   , an electronic device  1000  includes a plurality of antenna modules ANT 1  to ANT 4  and a plurality of transceiver circuit modules  1210   a  to  1210   d . In relation to this, the transceiver circuit modules  1210   a  to  1210   d  may correspond to a transceiver circuit  1250  described above. Alternatively, the transceiver circuit modules  1210   a  to  1210   d  may be a partial configuration of the transceiver circuit  1250  or a partial configuration of a front-end module arranged between the antenna modules ANT 1  to ANT 4  and the transceiver circuit  1250 . 
     The antenna modules ANT 1  to ANT 4  may be configured as an array antenna in which a plurality of antenna elements are arranged. A number of the antenna elements of the antenna modules ANT 1  to ANT 4  is not limited to two, three, four, or the like as illustrated in the drawing. For example, the number of the antenna elements of the antenna modules ANT 1  to ANT 4  may extend to 2, 4, 8, 16, or the like. In addition, the antenna elements of the antenna modules ANT 1  to ANT 4  may be selected in a same number or in different numbers. The plurality of antenna modules ANT 1  to ANT 4  may be arranged in different areas in a display, or in a lower portion or on a side surface of the electronic device. The plurality of antenna modules ANT 1  to ANT 4  may be arranged in an upper portion, a left portion, a lower portion, or a side portion of the display. However, an arrangement structure thereof is not limited thereto. As another example, the antenna modules ANT 1  to ANT 4  may be arranged in an upper left portion, an upper right portion, a lower left portion, or a lower right portion of the display. 
     The antenna modules ANT 1  to ANT 4  may be configured to transmit or receive a signal in a specific direction in any frequency band. For example, the antenna modules ANT 1  to ANT 4  may operate in any one of a 28 GHz band, a 39 GHz band, and a 64 GHz band. 
     The electronic device may maintain a connection state with a different entity through two or more of the antenna modules ANT 1  to ANT 4  including first to fourth antenna modules, or perform a data transmitting or receiving operation to maintain the connections state described above. In relation to this, the electronic device corresponding to a display device may transmit or receive data with a first entity through the first antenna module ANT 1 . Also, the electronic device may transmit or receive data with a second entity through the second antenna module ANT 2 . As an example, the electronic device may transmit or receive data with a mobile terminal UE through the first antenna module ANT 1 . The electronic device may transmit or receive data with a control device such as a set-top box or an access point (AP) through the second antenna module ANT 2 . 
     Data may be transmitted or received with another entity through other antenna modules, e.g., the third antenna module ANT 3  and the fourth antenna module ANT 4 . As another example, dual connection or MIMO may be performed through at least one of the first and second entities both previously connected via the third antenna module ANT 3  and the fourth antenna module ANT 4 . 
     Mobile terminals UE 1  and UE 2  may be arranged on a front surface area of the electronic device, and configured to communicate with the first antenna module ANT 1 . The set-top box (STB) or the access point AP may be arranged in a lower portion of the electronic device, and configured to communicate with the second antenna module ANT 2 , but is not limited thereto. As another example, the second antenna module ANT 2  may include both a first antenna radiating toward a lower region and a second antenna radiating toward a front region. Accordingly, the second antenna module ANT 2  may communicate with the set-top box (STB) or the access point AP through the first antenna, and with one of the mobile terminals UE 1  and UE 2  through the second antenna. 
     One of the mobile terminals UE 1  and UE 2  may be configured to perform MIMO with the electronic device. As an example, the mobile terminal UE 1  may be configured to perform MIMO while performing beamforming with the electronic device. As described above, the electronic device corresponding to the image display device may perform high-speed communication with another electronic device or the set-top box STB through a WiFi wireless interface. As an example, the electronic device may perform high-speed communication in a 60 GHz band with another electronic device or the set-top box STB through the 802.11ay wireless interface. 
     The transceiver circuit modules  1210   a  to  1210   d  may operate to process a transmission signal and a reception signal in an RF frequency band. Here, the RF frequency band may be any frequency band of a millimeter band, such as a 28 GHz band, a 39 GHz band, and a 64 GHz band, as described above. The transceiver circuit modules  1210   a  to  1210   d  may be referred to as RF sub-modules  1210   a  to  1210   d . In this case, a number of the RF sub-modules  1210   a  to  1210   d  is not limited to four, and may be changed to an arbitrary number of two or more according to applications. 
     In addition, the RF sub-modules  1210   a  to  1210   d  may include an up-conversion module and a down-conversion module both configured to convert a signal in the RF frequency band into a signal of in an IF (intermediate frequency) band or convert a signal in the IF frequency band into a signal in the RF frequency band. To this end, the up-conversion module and the down-conversion module may include a local oscillator (LO) capable of performing up-frequency conversion and down-frequency conversion. 
     With respect to the plurality of RF sub-modules  1210   a  to  1210   d , a signal may be transmitted from one of the transceiver circuit modules  1210   a  to  1210   d  to another transceiver circuit module adjacent thereto. Accordingly, a configuration may be such that the signal is transmitted to all of the transceiver circuit modules  1210   a  to  1210   d  at least once. 
     To do so, a data transfer path having a loop structure may be added. In relation to this, through a transmission path P 2  having the loop structure, the RF sub-modules  1210   b  and  1210   c  adjacent to each other may bidirectionally transmit a signal. 
     Alternatively, a data transfer path having a feedback structure may be added. In relation to this, through the data transfer path having the feedback structure, at least one sub-module, that is, the sub-module  1210   c  may transmit a signal to the remaining sub-modules  1210   a ,  1210   b , and  1210   d  unidirectionally. 
     The plurality of RF sub-modules may include the first to fourth RF sub-modules  1210   a  to  1210   d . In relation to this, a signal from the first RF sub-module  1210   a  may be transmitted to the RF sub-module  1210   b  and the fourth RF sub-module  1210   d  both adjacent thereto. In addition, the second RF sub-module  1210   b  and the fourth RF sub-module  1210   d  may transmit the signal to the third RF sub-module  1210   c  adjacent thereto. In this case, when bidirectional transmission between the second RF sub-module  1210   b  and the third RF sub-module  1210   c  may be performed as shown in  FIG.  4   , this may be referred to as a loop structure. On the other hand, when only omnidirectional transmission may be performed between the second RF sub-module  1210   b  and the third RF sub-module  1210   c , this may be referred to as a feedback structure. In the feedback structure, at least two signals may be transmitted to the third RF sub-module  1210   c.    
     However, structures are not limited thereto, and a baseband module may be included only in a specific module among the first to fourth RF sub-modules  1210   a  to  1210   d  depending on applications. Alternatively, depending on applications, the baseband module may not be included in the first to fourth RF sub-modules  1210   a  to  1210   d , but may be configured as a separate control unit, that is, a baseband processor  1400 . For example, a control signal may be transmitted only by a separate control unit, that is, the baseband processor  1400   
     Hereinafter, with respect to the electronic device illustrated in FIG. 1  and including the wireless interface of  FIG.  2   , a specific configuration and function are described. Transmission or reception of data between electronic devices needs to be performed using a communication service in a mmWave band therebetween. In relation to this, a wireless audio-video (AV) service and/or high-speed data transmission may be provided using the 802.11ay wireless interface as a mmWave wireless interface. This is not limited to the 802.11ay wireless interface, and any wireless interface of a 60 GHz band may be adopted. In relation to this, a 5G or 6G wireless interface using a 28 GHz band or a 60 GHz band may be used for high-speed data transmission between electronic devices. 
     There is such a problem that there is no specific solution for an antenna and an RFIC configured to provide a wireless interface in an electronic device such as an image display device, in order to transmit an image with a resolution of 4K or higher. In particular, transmitting or receiving wireless AV data with another electronic device needs to be performed by taking into account a situation in which an electronic device such as an image display device is arranged on a wall of a building or on a table. To do so, it is needed to present a specific configuration with respect to an area of the image display device, in which the antenna and the RFIC are to be arranged, and a structure of the antenna. 
     In relation to this,  FIG.  5 A  illustrates a configuration in which a multi-layer circuit substrate in which an array antenna module is arranged is connected to an RFIC, in relation to the present specification. Specifically, in relation to the present specification, a structure of an AIP (antenna in package) module and an antenna module structure implemented on a flexible substrate are illustrated. 
     Referring to (a) of  FIG.  5 A , the AIP module is configured as an RFIC-PCB-antenna integrated type for mmWave band communication. In relation to this, an array antenna module  1100 - 1  may be configured integrally a multi-layer PCB, that is, a multi-layer substrate as illustrated in (a) of  FIG.  5 A . Accordingly, the array antenna module  1100 - 1  configured integrally with the multi-layer PCB may be referred to as an AIP module. Specifically, the array antenna module  1100 - 1  may be arranged in one side area of the multi-layer substrate. In relation to this, a first beam B 1  may be provided in a side area of the multi-layer substrate using the array antenna module  1100 - 1  arranged on one side area of the multi-layer substrate. 
     On the other hand, referring to (b) of  FIG.  5 A , an array antenna module  1100 - 2  may be arranged on the multi-layer substrate. The arrangement of the array antenna module  1100 - 2  is not limited to the structure of (b) of  FIG.  5 A , but may be arranged on any layer in the multi-layer substrate. In relation to this, a second beam B 2  may be provided in a front surface region of the multi-layer substrate using the array antenna module  1100 - 2  arranged on any layer of the multi-layer substrate. In relation to this, in a case of the AIP module in which the array antenna module is provided integrally, an array antenna may be arranged on a same PCB as the RFIC to minimize a distance between the RFIC and the antenna. 
     The antenna of the AIP module may be implemented using a multi-layer PCB manufacturing process, and radiate a signal in a vertical/side direction of the PCB. In relation to this, double polarization may be implemented using a patch antenna or a dipole/monopole antenna. Accordingly, the first array antenna  1100 - 1  shown in (a) of  FIG.  5 A  may be arranged on the side area of the multi-layer substrate, and the second array antenna  1100 - 2  shown in (b) of  FIG.  5 A  may be arranged on the side area of the multi-layer board. Therefore, the first beam B 1  may be generated through the first array antenna  1100 - 1 , and the second beam B 2  may be generated through the second array antenna  1100 - 2 . 
     The first array antenna  1100 - 1  and the second array antenna  1100 - 2  may be configured to have same polarization. Alternatively, the first array antenna  1100 - 1  and the second array antenna  1100 - 2  may be configured to have orthogonal polarization. In relation to this, the first array antenna  1100 - 1  may operate as a vertically polarized antenna and also operate as a horizontally polarized antenna. For example, the first array antenna  1100 - 1  may be a monopole antenna having vertical polarization, and the second array antenna may be a patch antenna having horizontal polarization. 
       FIG.  5 B  is a conceptual diagram illustrating antenna structures having different radiation directions. 
     Referring to (a) of  FIG.  5 A  and (a) of  FIG.  5 B , a radiation direction of the antenna module arranged in the side area of the multi-layer substrate corresponds to a side direction. In relation to this, the antenna implemented on the flexible substrate may be configured as a radiating element such as a dipole/monopole antenna. That is, antennas implemented on the flexible substrate may be end-fire antenna elements. 
     In relation to this. end-fire radiation may be implemented by an antenna radiating in a horizontal direction with the substrate. The end-fire antenna may be implemented as a dipole/monopole antenna, a Yagi-dipole antenna, a Vivaldi antenna, a substrate integrated waveguide (SIW) horn antenna, or the like. In relation to this, the Yagi-dipole antenna and the Vivaldi antenna have horizontal polarization characteristics. One of the antenna modules arranged in the image display device described herein needs a vertical polarization antenna. Accordingly, there is a need to present an antenna structure capable of minimizing an antenna exposure area while operating as a vertically polarized antenna. 
     Referring to (b) of  FIG.  5 A  and (a) of  FIG.  5 B , a radiation direction of the antenna module arranged in the front area of the multi-layer substrate corresponds to a front direction. In relation to this, an antenna implemented on the AIP substrate may be configured as a radiating element such as a patch antenna. That is, the antenna arranged in the AIP module may be a broadside antenna element radiating in the broadside direction. 
     The multi-layer substrate in which the array antenna is arranged may be provided integrally with the main substrate or may be configured to be coupled to the main substrate as a modular type by a connector. In relation to this,  FIG.  5 C  illustrates a combination structure between a multi-layer substrate and a main substrate. Referring to (a) of  FIG.  5 C , a structure in which an RFIC  1250  and a modem  1400  are integrally provided on a multi-layer substrate  1010  is shown. The modem  1400  may be referred to as the baseband processor  1400 . Accordingly, the multi-layer substrate  1010  is integrally provided integrally with the main substrate. The integrated structure may be applied to a structure in which only one array antenna module is arranged in the electronic device. 
     On the other hand, the multi-layer board  1010  and the main board  1020  may be configured to be coupled to each other as a modular type by a connector. Referring to (b) of  FIG.  5 C , in relation to this, the multi-layer substrate  1010  may be configured to interface with the main substrate  1020  through a connector. In this case, the RFIC  1250  may be arranged on the multi-layer substrate  1010 , and the modem  1400  may be arranged on the main substrate  1020 . Accordingly, the multi-layer substrate  1010  may be provided as a separate substrate with the main substrate  1020  and configured to be coupled through a connector 
     Such a modular structure may be applied to a structure in which a plurality of array antenna modules are arranged in the electronic device. Referring to (b) of  FIG.  5 C , the multi-layer substrate  1010  and a second multi-layer substrate  1010   b  may be configured to interface with the main substrate  1020  through a connector connection. The modem  1400  arranged on the main substrate  1020  is configured to be electrically coupled to RFICs  1250  and  1250   b  arranged on the multi-layer substrate  1010  and the second multi-layer substrate  1020 , respectively. 
     When the AIP module is arranged in a lower portion of the electronic device such as the image display device, communication needs to be performed with other communication modules arranged in a lower direction and a front direction. In relation to this,  FIG.  6    is a conceptual diagram illustrating a plurality of communication modules arranged in a lower portion of the image display device  100 , and communication between the communication modules and other communication modules arranged in a front direction from the image display device. Referring to (a) of  FIG.  6   , different communication modules  1100 - 1  and  1100 - 2  may be disposed in a lower portion of the image display device  100 . Referring to (b) of  FIG.  6   , the image display device  100  may perform communication with a communication module  1100   b  arranged below the image display device  100  through the antenna module  1100 . Communication may be performed with the second communication module  1100   c  arranged in front of the image display device  100  through the antenna module  1100  of the image display device  100 . In addition, communication may be performed with the third communication module  1100   d  arranged by a side of the image display device  100  through the antenna module  1100  of the image display device  100 . 
     In relation to this, the communication module  1100   b  may be a set-top box or an access point (AP) configured to transmit AV data to the image display apparatus  100  through the  802 . 11 ay wireless interface at a high speed, but is limited thereto. The second communication module  1100   c  may be any electronic device configured to transceive data to/from the image display device  100  at a high speed through the 802.11ay wireless interface. To perform wireless communication with the communication modules  1100   b ,  1100   c , and  1100   d  arranged in front of, below, and by a side of the image display device  100 , respectively, the antenna module  1100  having a plurality of array antennas provide beams in different directions. Specifically, the antenna module  1100  may provide beams in a front direction B 2 , a lower direction B 1 , and a side direction B 3  through different array antennas, respectively. 
     In the AIP module structure as illustrated in (a) of  FIG.  5 A , an antenna height may increase according to an RFIC driving circuit and a heat dissipation structure. Also, depending on a type of an antenna that is being used, an antenna height may increase in the AIP module structure as shown in (a) of  FIG.  5 A . On the other hand, in the antenna module structure implemented in a side area of the multi-layer substrate as illustrated in (b) of  FIG.  5 A , an antenna in a low-profile shape may be implemented. 
     With respect to an antenna module that may be implemented as illustrated in  FIGS.  1  and  2    and arranged inside or on a side surface of the electronic device of  FIGS.  4  and  6   , and is illustrated in  FIGS.  5 A to  5 C , a detailed configuration thereof is described. 
     A communication module including an antenna may be provided so that the electronic device such as the image display device may perform communication with a neighboring electronic device. Recently, as a display area of the image display device is enlarged, an arrangement space of the communication module including the antenna is reduced. Accordingly, there is an increasing need for arranging an antenna in a multi-layer circuit board on which the communication module is implemented. 
     A WiFi wireless interface may be taken into account, as an interface for a communication service between electronic devices. When using such a WiFi wireless interface, a mmWave band may be used for high-speed data transmission between electronic devices. In particular, high-speed data transmission between electronic devices may be performed using a wireless interface such as the 802.11ay wireless interface. 
     In relation to this, an array antenna capable of operating in a mmWave band may be mounted in the antenna module. However, electronic components such as an antenna and a transceiver circuit arranged in such an antenna module are configured to be electrically connected to each other. In relation to this, electronic components arranged on different layers may be electrically connected to each other through a multi-layered transmission line, and thus a vertical via structure may be provided. 
     In a high frequency band such as a mmWave band, there is such a problem that impedance mismatch between transmission lines and a line loss may occur significantly due to the vertical via structure. In addition, when a plurality of antennas are arranged in the multi-layer substrate, a large amount of line loss may occur according to provision of detour paths of transmission lines in order to avoid overlap between the transmission lines. 
     The present disclosure is directed to solving the aforementioned problems and other drawbacks. The present disclosure is directed to solving the aforementioned problems and other drawbacks. Another aspect of the present disclosure is to provide an antenna module including a multi-layer impedance transformer operating in a millimeter wave band, and an electronic device including the antenna module. 
     Another aspect of the present disclosure is to solve such a problem that which line loss increases due to the provision of a detour path of a plurality of feeding lines configured to feed a plurality of antenna elements constituting an array antenna in a mmWave band. 
     Another aspect of the present disclosure is to solve such a problem that impedance mismatch due to vertical vias increases through a multi-layer impedance conversion structure between an RFIC and an antenna element arranged on a PCB having a form of a multi-layer substrate. 
     Another aspect of the present disclosure is to provide a broadband feeding line structure capable of improving impedance matching characteristics of an antenna element electrically connected to a feeding line inside a PCB having a form of a multi-layer substrate 
       FIGS.  7 A and  7 B  illustrate a comparison between arrangement structures of an RF line and a power line in a configuration in which RFICs corresponding to transceiver circuits are connected to different antennas. 
     As illustrated in  FIG.  7 A , when a connection line is provided without a vertical via structure, other RF lines or power lines L 1  to L 4  may be arranged in paths through which feeding lines F 1  to F 4  are connected from the RFIC  1250  to the antennas ANT 1  to ANT 4 . In this case, the RF lines or the power lines L 1  to L 4  need to be configured as detour paths in an area in which the antennas ANT 1  to ANT 4  are not arranged. For example, the RF line or the power lines L 1  to L 4  provide detour paths in a form of a horizontal line. In relation to this, a first type of antennas ANT 1  to ANT 4  may be arranged on the multi-layer substrate or on one layer inside the multi-layer substrate. A second type of antennas ANT 1   b  to ANT 4   b  may be disposed on a side surface of the multi-layer substrate. The first type of antennas ANT 1  to ANT 4  may be antennas configured to radiate a signal toward an upper or lower portion of the multi-layered substrate, and the second type of antennas ANT 4   b  to ANT 4   b  may be antennas configured to radiate a signal toward a side surface of the multi-layered substrate. 
     On the other hand, as illustrated in  FIG.  7 B , the RF lines or the power lines L 1  to L 4  may be arranged through another layer in a region in which the antennas ANT 1  to ANT 4  are disposed, without having to provide a detour path. Accordingly, by moving to another layer through a vertical via in a vertical line without having to detour along a horizontal line, the RF lines or the power lines L 1  to L 4  may be provided in a straight line. Accordingly, by shortening a length of the feeding lines F 1  to F 4  and the RF lines L 1  to L 4 , a line loss may be reduced. 
     In relation to this, the antennas ANT 1  to ANT 4  may be the first type of antennas, and the second type of antennas ANT 1   b  to ANT 4   b  may be arranged in a lower end region. A structure in which impedance transformers TR 1  and TR 2  are provided to have a vertical via  1130  at a center therebetween may be applied to the feeding lines F 1  to F 4  connected to the first type antennas ANT 1  to ANT 4 . Also, a structure in which the impedance transformers TR 1  and TR 2  are provided to have the vertical via  1130  at a center therebetween may be applied to the RF lines L 1  to L 4  connected to the second type antennas ANT 1   b  to ANT 4   b . In relation to this, the first type of antennas ANT 1  to ANT 4  may be arranged on the multi-layer substrate or on one layer inside the multi-layer substrate. The second type of antennas ANT 1   b  to ANT 4   b  may be disposed on a side surface of the multi-layer substrate. The first type of antenna may be an antenna configured to radiate a signal toward an upper or lower portion of the multi-layered substrate, and the second type of antenna may be an antenna configured to radiate a signal toward a side surface of the multi-layered substrate. 
     According to an embodiment described herein, in a line connection structure of  FIG.  7 B , the impedance transformers TR 1  and TR 2  in a form of a λ/4 conversion device are provided to have the vertical via  1130  therebetween in the transmission lines TL 1  and TL 2  arranged in different layers. Accordingly, the feeding lines F 1  to F 4  may be provided in a straight line in a direction in which the antennas ANT 1  to ANT 4  are arranged through a via. In this case, performance degradation due to a via may be prevented using a structure in which a width of lines facing each other having the vertical via  1130  at a center therebetween becomes thicker, and then, becomes thinner again. 
     With respect to the antenna module including the multi-layer substrate described herein, an impedance conversion structure in which vertical vias are taken into account is described.  FIG.  8    illustrates a configuration of an antenna module including a multi-layer substrate according to the present specification.  FIG.  8    is a side view of the antenna module  1100  in a mmWave band capable of increasing a coverage by radiating electromagnetic waves in various directions. 
     As illustrated in  FIG.  8   , the antenna module  1100  may be configured to include the transceiver circuit  1250 , a first transmission line  1120   a , a second transmission line  1120   b , and a vertical via  1130 . Since the antenna module  1100  is implemented to include a plurality of multi-layer substrates, the antenna module  1100  may be referred to as an antenna assembly  1100 . 
     The transceiver circuit  1250  may be configured to be arranged on the antenna module  1110  including the multi-layer substrate. The transceiver circuit  1250  may be arranged on an uppermost layer of the multi-layer substrate, but is not limited thereto. Referring to  FIG.  8   , the multi-layer substrate in a form of a printed circuit board (PCB) includes six layers, but is not limited thereto. The multi-layer substrate may be configured in various numbers of layers depending on an application. An RFIC corresponding to the transceiver circuit  1250  is attached to a multi-layer substrate corresponding to the PCB, and configured to transmit or receive a signal in a mmWave band through antennas  1100 U,  1100 S, and  1100 L. In relation to this, since the antenna  1100 U is configured to radiate a signal upwards, the antenna  1100 U may be referred to as an upper antenna. In addition, since the antenna  1100 L is configured to radiate a signal downwards, the antenna  1100 L may be referred to as a lower antenna. Also, since the antenna  1100 S is configured to radiate a signal sidewards, the antenna  1100 S may be referred to as a side antenna. 
     The upper antenna  1100 U and the lower antenna  1100 L may be configured as a first type of radiator to radiate signals in an upper direction and a lower direction that are perpendicular to the multi-layer substrate. The upper antenna  11000  and the lower antenna  1100 L may be configured as a first type of antenna for radiating signals in a broadside direction, like a patch antenna. On the other hand, the side antenna  1100 S may be configured as a second type of radiator for radiating a signal in a side direction parallel to the multi-layer substrate. The side antenna  1100 S may be configured as a second type of antenna for radiating a signal in an end-fire direction, like a dipole antenna or a monopole antenna. 
     Accordingly, the antenna module  1100  may be configured to include the lower antenna  1100 L and the side antenna  1100 S arranged inside the multi-layer substrate and configured to radiate a signal in the side direction of the multi-layer substrate. In addition, the antenna module  1100  may be configured to further include the upper antenna  1100 U. 
     To improve directivity of the side antenna  1100 S, a ground via wall  1130   c  may be arranged. In relation to this, as described above, the side antenna  1100 S may be arranged inside the multi-layer substrate and configured to radiate signals toward a side direction of the multi-layer substrate. The ground via wall  1130   c  may include a plurality of layers arranged at a further inner position in the multi-layer substrate compared to the side antenna  1100 S to improve directivity, toward a side direction, of a signal radiated by the side antenna  1100 S. In other words, the ground via wall  1130   c  may be configured as a vertical connection portion connecting via pads on first and second grounds G 1  and G 2  to each other. 
     The first transmission line  1120   a  may be arranged on a first layer of the antenna module  1100  and configured to be electrically connected to the transceiver circuit  1250 . The second transmission line  1120   b  may be arranged on a second layer of the antenna module  1100  and configured to be electrically connected to an antenna. Here, the first layer and the second layer are any layers in the multi-layer substrate on which the first transmission line  1120   a  and the second transmission line  1120   b  are arranged. As an example, referring to  FIG.  8   , the first layer may be a first layer L 1  that is an uppermost layer, and the second layer may be a third layer L 3  inside the multi-layer substrate. Accordingly, the first transmission line  1120   a  may be arranged on an upper layer of the PCB on which the RFIC  1250  is arranged, or a lower layer of the PCB. The second transmission line  1120   b  may be arranged on a layer in the PCB, but is not limited thereto. The arrangement of the second transmission line  1120   b  may vary depending on an application. 
     A feeding line for connecting the RFIC  1250  to the antennas  1100 U,  1100 S, and  1100 L may be arranged on or inside the multi-layer substrate. As illustrated in  FIG.  8   , the upper antenna  1100 U and the RFIC  1250  are arranged on the uppermost layer of the multi-layer substrate, and thus, may be directly connected to each other without a vertical via connection. Meanwhile, when the upper antenna  11000  is arranged on a layer other than the uppermost layer, for example, the second layer L 2 , the upper antenna  11000  may be connected to the RFIC  1250  through a vertical via connection. 
     The lower antenna  1100 L may be configured to be connected to the RFIC  1250  using the first transmission line  1120   a , the vertical via  1130  and the second transmission line  1120   b , described above. The lower antenna  1100 L may be configured to be electrically connected to the second transmission line  1120   b  through a second vertical via  1132 . The lower antenna  1100 L may be a lower antenna configured to radiate a signal in a lower direction of the antenna module  1100 . 
     A vertical via  1120  may be configured to vertically connect the first transmission line  1120   a  to the second transmission line  1120   b . In this case, the vertical via  1120  may include a via pad VP and a vertical connection part VC to connect the feeding lines on the upper layer and the lower layer, for example, the first transmission line  1120   a  and the second transmission line  1120   b  to each other. A distance between one end of the via pad VP and an adjacent ground via  1130   a  or  1130   b  may be referred to as a via clearance interval. 
     The ground vias  1130   a  and  1130   b , i.e., first and second ground vias may be configured to connect different grounds, for example, the first ground G 1  and the second ground G 2  to each other. The first ground via  1130   a  may be provided adjacent to one end of the second transmission line  1120   b . Also, the second ground via  1130   b  may be provided adjacent to the other end of the second transmission line  1120   b.    
     The vertical via  1130  including the via pad VP and the vertical connection part VC may be referred to as a signal via or a feed via. An impedance of a feeding line in the mmWave band may be configured to be less than 50 ohms, due to a via tolerance between the ground via  1130   b  and the feed via  1130  including the via pad VP and the vertical connection part VC, Accordingly, impedance mismatching between the antennas  1100 U,  1100 S, and  1100 L and the RFIC  1250  may occur. 
     A feeding line corresponding to the first transmission line  1120   a  may be configured as a microstrip line arranged on the uppermost layer or the lowermost layer of the multi-layer substrate corresponding to the PCB. In this case, even when the feeding line is not arranged on the uppermost layer or lowermost layer of the multi-layer substrate, when a ground is not arranged over or below the feeding line, the feeding line may be regarded as a microstrip line. On the other hand, a feeding line corresponding to the second transmission line  1120   b  may be configured as a strip line arranged in the multi-layer substrate corresponding to the PCB. As illustrated in  FIG.  8   , a first ground G 1  and a second ground G 2  are arranged on and below the second transmission line  1120   b , respectively, and thus, the second transmission line  1120   b  corresponds to a structure of the strip line. 
     Accordingly, the first transmission line  1120   a  may be configured as a microstrip line in which an air layer is provided without a dielectric on a conductive line arranged on a dielectric. The second transmission line  1120   b  may be configured as a strip line in which dielectrics are disposed on and below the conductive line, respectively, and the grounds G 1  and G 2  are arranged on and below the dielectrics, respectively. 
     Referring to  FIG.  8    with respect to an antenna and a feeding line arrangement structure, patch antennas corresponding to the upper antenna  11000  and the lower antenna  1100 D may be arranged on the first layer L 1  that is an uppermost layer and the sixth layer L 6  that is a lowermost layer, respectively. The first ground G 1  operates as a ground of the patch antenna and an upper ground of the second transmission line  1120   b , and may be arranged on the second layer L 2 . The second ground G 2  operates as a lower ground of the second transmission line  1120   b  and may be arranged on a fourth layer L 4 . 
     A feeding line including the second transmission line  1120   b  to feed the lower antenna  1100 L may be arranged on the third layer L 3 . In this case, a restriction may occur in an arrangement space of the feeding line configured to feed the side antenna  1100 S arranged on the third layer L 3 . In particular, when the ground via wall  1130   c  operating as a reflector of the side antenna  1100 S is arranged on the second layer (L 2 ) to the fourth layer (L 4 ), a constraint may occur in the arrangement space of the feeding line configured to feed the side antenna  1100 S. A plurality of ground vias  1130   a ,  1130   b , and  1130   c  including the ground via wall  1130   c  may be arranged in the multi-layer substrate. 
     To relieve such a constraint condition on the arrangement space, the side antenna  1100 S, such as a dipole antenna, may be arranged on any of the first to sixth layers L 1  to L 6 . Alternatively, the side antenna  1100 S may be arrange on any of the second to fourth layers L 2  to L 4 . In this case, a feeding line configured to feed the side antenna  1100 S may be provided through a region in which the ground vias  1130   a ,  1130   b , and  1130   c  are not provided, and connected to the side antenna  1100 S. 
     An impedance matching structure having a vertical via connection between the transmission lines connecting the RFIC to the antenna disclosed herein is described in detail. In relation to this,  FIG.  9    illustrates an impedance matching structure having a vertical via connection between the transmission lines connecting the RFIC to the antenna described herein. 
     Referring to  FIGS.  8  and  9   , a first impedance transformer  1121  in the first transmission line  1120   a  connected to the vertical via  1130  may be configured to have a first width W 1  and a first length L 1 . A second impedance transformer  1122  in the second transmission line  1120   b  connected to the vertical via  1130  may be configured to have a second width W 2  and the second length L 2 . 
     In the impedance matching structure disclosed herein, dimensions of the first impedance transformer  1121  and the second impedance transformer  1122  may be set within a predetermined range. In relation to this,  FIG.  10 A  illustrates reflection coefficient characteristics for each frequency according to a ratio L 1 /L 2  between lengths of the first and second impedance transformers  1121  and  1122 . In addition,  FIG.  10 A  illustrates reflection coefficient characteristics for each frequency according to a ratio W 1 /W 2  between widths of the first and second impedance transformers  1121  and  1122 . 
     Referring to  FIG.  10 A , when the ratio L 1 /L 2  between the lengths of the first and second impedance transformers  1121  and  1122  is 0.65, 0.85, or 1.20, this indicates stable reflection loss performance of −15 dB or less in a whole band of 57.2 to 70.2 GHz. However, when the ratio L 1 /L 2  between the lengths of the first and second impedance transformers is 0.45 or 1.35, reflection loss performance has a value of −15 dB or greater in an operating frequency band. Thus, it may be understood that impedance matching performance is attenuated. 
     Accordingly, referring to  FIGS.  8 ,  9  and  10 A , the ratio L 1 /L 2  between the first length L 1  of the first impedance transformer  1121  and the second length L 2  of the second impedance transformer  1122  may be set to be within a range from 
     Referring to  FIG.  10 B , when the ratio W 2 /W 1  between widths of the first and second impedance transformers  1121  and  1122  is 0.38, 0.48, or 0.57, this indicates stable reflection loss performance of −15 dB or less in a whole band of 57.2 to 70.2 GHz. However, when the ratio W 2 /W 1  between the widths of the first and second impedance transformers is 0.32 or 0.71, reflection loss performance has a value of −15 dB or greater in the operating frequency band. Thus, it may be understood that impedance matching performance is attenuated. 
     Accordingly, referring to  FIGS.  8 ,  9  and  10 B , the ratio W 1 /W 2  between a first width W 11  of the first impedance transformer  1121  to the second width W 2  of the second impedance transformer  1122  may be set to be within a range from 0.32 to 0.71. 
     The vertical via  1130  is essentially needed to configure the microstrip line and strip line feeding structure proposed herein. Mismatching between the antenna and the transmission line may occur due to the vertical via  1130  implemented on the multi-layer substrate of the PCB, in an antenna operating in a high band such as a mmWave band. 
     To resolve the mismatching between the antenna and the transmission line, the first and second transmission lines  1120   a  and  1120   b  may be connected to each other at both sides to have the vertical via  1130  therebetween, and may include the first and second impedance transformers  1121  and  1122 . 
       FIG.  11    illustrates an equivalent circuit of an impedance conversion structure proposed herein to solve a problem described above.  FIGS.  12 A to  12 C  illustrate transmission line structures connected through a vertical via, respectively, according to various embodiments. 
     Referring to  FIGS.  8  and  9   , the first and second transmission lines  1120   a  and  1120   b  include the first and second impedance transformers  1121  and  1122  connected at both sides to have the vertical via  1130  therebetween. 
     Referring to  FIGS.  8  to  11   , the first and second impedance transformers  1121  and  1122  are provided to have a length of ¼ of a wavelength corresponding to an operating frequency, and thus may be referred to as a λ/4 conversion device. As such, 50 ohm impedance matching may be performed over a wide bandwidth, using the first and second impedance transformers  1121  and  1122  having a form of the λ/4 conversion device and arranged to face each other at both sides with the vertical via  1130  at a center therebetween. 
     Referring to  FIGS.  8  to  11   , the vertical via  1130  may be modeled to have an electrical length corresponding to a load impedance R L and a vertical height h. When the antenna module operates in a low frequency band, an electrical length of the vertical via  1130  may be ignored. However, an electrical length of the vertical via  1130  inside the antenna module operating in a high frequency band such as the mmWave band may not be ignored. Accordingly, in the first and second transmission lines  1120   a  and  1120   b  having a characteristic impedance Z 0 , that is, 50 ohms, the first and second impedance transformers  1121  and  1122  may be arranged to have a length of λ/4 or less at left and right sides with reference to the load impedance R L , respectively. In relation to this, a wavelength λ may be λ eff , which is a length reduced according to an effective dielectric constant of a substrate, e eff . In the embodiment, the load impedance R L  is configured for the vertical via  1130 . However, the scope of protection is not limited to the vertical via  1130 , and may extend to any connection structure between different transmission lines. 
     A characteristic impedance Z 1  of the first impedance transformer  1121  may be identical to or different from a characteristic impedance Z 2  of the second impedance transformer  1122 . The first and second impedance transformers  1121  and  1122  are λ/4 conversion devices having impedances of Z 1  and Z 2 , respectively, and are located on different layers. 
     (a) of  FIG.  11    illustrates the first and second impedance transformers  1121  and  1122  with a vertical via  1130  at a center therebetween. Referring to (a) of  FIG.  11   , one impedance transformer is arranged at one side with reference to the vertical via  1130 . The λ/4 conversion device described herein may be configured as a multi-level conversion device having three or more transformers as illustrated in (b) of  FIG.  11   . 
     With respect to the multi-level conversion device, the load impedances Z L  and R L  do not directly become 50 ohms through a single conversion device, but are converted through a plurality of impedance transformers in the multi-level conversion device. Referring to  FIGS.  8  to  10    and (b) of  FIG.  11   , a load impedance Z L  in the vertical via  1130  may be impedance-converted into the characteristic impedance Z 0  of 50 ohms through a plurality of impedance transformers  1121 - 1  to  1121 - 3 . 
     In relation to this, a number of the impedance transformers is not limited to three. A multi-level impedance conversion device including any number of, i.e., two or more impedance transformers may be provided. When two impedance transformers are provided, the two impedance transformers may be referred to as first and second impedance transformers, respectively. A load impedance of about 30 ohms in the vertical via  1130  is impedance-converted into about 40 ohms through the first impedance transformer, and then, into 50 ohms through the second impedance transformer. 
     A number of impedance transformers at one side may be provided to be different from a number of impedance transformers at the other side with reference to the vertical via  1130 . Referring to  FIGS.  8  to  11   , one of the first and second impedance transformers  1120   a  and  1120   b  may be configured as a single impedance conversion device. The other of the first and second impedance transformers  1120   a  and  1120   b  may be configured as a multi-level impedance conversion device including two or more impedance transformers. 
     Referring to  FIG.  12 A , the first and second transmission lines TL 1  and TL 2  are positioned on different layers with reference to the vertical via  1130  and connected to each other through the vertical via  1130 . In other words, the first and second transmission lines TL 1  and TL 2  may be connected to each other through the vertical via  1130  including a plurality of via pads VP 1 , VP 2 , . . . , VPn and a plurality of vertical connection parts VC 1 , VC 2 , . . . , VCn- 1 . The first and second transmission lines TL 1  and TL 2  may be implemented without an impedance transformer. However, a via clearance interval of  FIG.  8    between the first and second transmission lines TL 1  and TL 2  and the ground needs to be adjusted for impedance conversion. 
     Referring to  FIG.  12 B , the first transmission line TL 1  is arranged on a different layer from that of the second transmission line TL 2  or  1120   b  with reference to the vertical via  1130 , and connected thereto through the vertical via  1130 . In other words, the first transmission line TL 1  may be connected to the second transmission line TL 2  or  1120   b  having the second impedance unit  1122  through the vertical via  1130  including the via pads VP 1 , VP 2 , . . . , VPn and the vertical connection parts VC 1 , VC 2 , . . . , VCn- 1 . The first transmission line TL 1  may be implemented without an impedance transformer. However, a via clearance interval of  FIG.  8    between the first and second transmission lines TL 1  and TL 2  and the ground needs to be adjusted for impedance conversion. 
     To match an impedance distorted by the vertical via  1130  of  FIG.  12 B  back to Z 0 , the second impedance transformer  1122 , which is a λ/4 conversion device, is used in the second transmission line TL 2 . In this case, a line impedance of the second impedance transformer  1122  may be configured as Z 2  as illustrated in  FIG.  11   . Since the impedance distorted by the vertical via  1130  is considered lower than Z 0 , Z 2 &lt;Z 0  should be satisfied. Accordingly, a line width of the second impedance transformer  1122  is greater than that of the second transmission line TL 2 . Meanwhile, a line length of the second impedance transformer  1122  may be configured to have a length of λ/4 or less. 
     However, a configuration is not limited to the configuration of  FIG.  12 B . The second transmission line TL 2  may be connected to the vertical via  1130  without an impedance transformer, and the first transmission line TL 1  may be connected to the vertical via  1130  through an impedance transformer. 
     Referring to  FIG.  12 C , the first impedance transformer  1121  that is a A/ 4  conversion device may be further provided to the first transmission line TL 1 . Since it is deemed that an impedance of the first impedance transformer  1121  in the first transmission line TL 1  in a direction toward the vertical via  1130  is lower than Z 0 , Z 1 &lt;Z 0  should be satisfied. Accordingly, a line width of the second impedance transformer  1121  is greater than that of the second transmission line TL 2 . A length and a width of the first impedance transformer  1121  used in the first transmission line TL 1  may be configured to be identical to or different from those of the second impedance transformer  1122  used in the second transmission line TL 2  according to a design matter. 
     Referring to  FIGS.  8  to  11  and  12 C , the first transmission lines TL 1  or  1120   a  may be configured as a microstrip line, and the second transmission line TL 2  or  1120   b  may be configured as a strip line. An effective permittivity of the microstrip line on which an air layer is provided in an upper portion is lower than an effective permittivity of the strip line. Accordingly, a first width W 1  of the first transmission line TL 1  or  1120   a  may be configured to be greater than a second width W 2  of the second transmission line TL 2  or  1120   b.    
     Referring to  FIGS.  8  to  11  and  12 C , the first impedance transformer  1121  may be configured to have a first width W 1  corresponding to a first impedance in the microstrip line and a first length L 1  of a quarter wavelength that is a ¼ of a wavelength corresponding to an operating frequency. The first impedance transformer  1121  may be configured to perform impedance matching between a 50 ohm impedance of the first transmission line  1120   a  and a second impedance in an upper end region of the vertical via  1130 . 
     The second impedance transformer  1122  may be configured to have a second width W 2  corresponding to a third impedance in the strip line and a second length L 2  of a quarter wavelength that is a ¼ of a wavelength corresponding to an operating frequency. The second impedance transformer  1122  may be configured to perform impedance matching between a 50 ohm impedance of the second transmission line  1120   b  and a fourth impedance in an upper end region of the vertical via  1130 . 
     The first width W 1  of the first impedance transformer  1121  may be greater than a 50 ohm line width of the first transmission line  1120   a . Accordingly, the first impedance of the first impedance transformer  1121  may be configured to be less than 50 ohms. 
     The second width W 2  of the second impedance transformer  1122  may be configured to be greater than a 50 ohm line width of the second transmission line  1120   b  and less than the first width W 1 . Accordingly, the second impedance of the first impedance transformer  1122  may be configured to be less than 50 ohms. The second impedance of the second impedance transformer  1122  may be configured to be greater than the first impedance of the first impedance conversion unit  1121 . 
     Referring to  FIGS.  8  to  11  and  12 B , one of the first and second transmission lines  1120   a  and  1120   b  may be configured only as a transmission line having 50 ohms without an impedance transformer. For example, the first transmission line  1120   a  may be configured only as a transmission line having 50 ohms without an impedance transformer. To do so, the first width W 1  of the first impedance transformer  1121  may be configured to be same as a 50 ohm line width of the first transmission line  1120   a . In this case, the second width W 2  of the second impedance transformer  1122  may be configured to be different from (greater than) a 50 ohm line width of the second transmission line  1120   b.    
     As another example, the second transmission line  1120   b  may be configured only as a transmission line having 50 ohms without an impedance transformer. To do so, the second width W 2  of the second impedance transformer  1122  may be configured to be same as a 50 ohm line width of the second transmission line  1120   b . In this case, the first width W 1  of the first impedance transformer  1121  may be configured to be different from (greater than) a 50 ohm line width of the first transmission line  1120   a.    
     A multi-layer impedance conversion structure according to another embodiment of the present specification may be configured as an asymmetric structure including a different number of impedance transformers with reference to the vertical via  1130 . In relation to this,  FIG.  13 A  illustrates a configuration in which impedance-conversion is performed via a plurality of impedance transformers in a case of vertical via connection in a microstrip line.  FIG.  13 B  illustrate a configuration in which impedance-conversion is performed via a plurality of impedance transformers in a case of vertical via connection in a strip line. 
     Referring to  FIG.  13 A , the first transmission line  1120   a  may be configured to include the first impedance transformer  1121  and a third impedance transformer  1123 . The first impedance transformer  1121  may be connected to the vertical via  1130  and configured to have the first width W 1  and the first length L 1 . The third impedance transformer  1123  may be connected to one end of the first impedance transformer  1121  and may be configured to have a third width W 3  and a third length L 3 . The third impedance transformer  1123  may be configured to perform impedance conversion between the first impedance transformer  1121  and the first transmission line  1120   a  with 50 ohm impedance. To do so, the third width W 3  of the third impedance conversion unit  1123  may be configured to be less than the first width W 1  of the first impedance conversion unit  1121 , and greater than a 50 ohm line width of the first transmission line  1120   a.    
     Referring to  FIG.  13 B , the second transmission line  1120   b  may be configured to include the second impedance transformer  1122  and a fourth impedance transformer  1124 . The second impedance transformer  1122  may be connected to the vertical via  1130  and configured to have the second width W 2  and the second length L 2 . The fourth impedance transformer  1124  may be connected to one end of the second impedance transformer  1122  and configured to have a fourth width W 4  and a fourth length L 4 . The fourth impedance transformer  1124  may be configured to perform impedance conversion between the second impedance transformer  1122  and the second transmission line  1120   b  with 50 ohm impedance. To do so, the fourth width W 4  of the third impedance transformer  1124  may be configured to be less than the second width W 2  of the second impedance transformer  1122 , and greater than a 50 ohm line width of the second transmission line  1120   b.    
     The embodiment of  FIG.  13 A  may be combined with the embodiment of  FIG.  9    so that a region of the microstrip line may include two or more impedance transformers, and a region of the strip line may include one impedance transformer. As another example, the embodiment of  FIG.  13 A  may be combined with the embodiment of  FIG.  9    so that the microstrip line region may include two or more impedance transformers and the strip line region may also include two impedance transformers. 
     The embodiment of  FIG.  13 B  may be combined with the embodiment of  FIG.  9    so that the strip line region may include two or more impedance transformers, and the microstrip line region may include one impedance transformer. 
     In the multi-layer impedance conversion structure described herein, a ground layer may be arranged on each layer of the vertical via  1130 . In relation to this,  FIG.  14 A  illustrates a structure in which the vertical via is spaced apart from the ground layer on each layer by a same distance in a multi-layered impedance conversion structure.  FIG.  14 B  illustrates a structure in which the vertical via is spaced apart from the ground layers on respective layers by different distances in a multi-layered impedance conversion structure. 
     Referring to  FIGS.  8 ,  14 A, and  14 B , the vertical via  1130  may be configured to vertically connect a microstrip line TL 1  arranged on an uppermost layer L 1  of the multi-layer substrate to a strip line TL 2  arranged in the multi-layer substrate. To do so, the vertical via  1130  may be configured to include a plurality of via pads VP 1 , VP 2 , . . . , VPn and a plurality of vertical connection parts VC 1 , VC 2 , . . . , VCn- 1 . The via pads VP 1 , VP 2 , . . . , VPn are arranged on different layers L 1  to Ln, and may be arranged on same layers as the grounds G 1 , G 2 , . . . , Gn, respectively, with a gap GA having a certain width therebetween. 
     In relation to this, a distance from a center of the vertical via  1130  to each of the grounds G 1 , G 2 , . . . , Gn arranged on each layer may be defined as a gap. Referring to  FIG.  14 A , gap intervals from the center of the vertical via  1130  to the grounds G 1 , G 2 , . . . , Gn may be same for respective layers. 
       FIG.  14 B  illustrates a modified design structure of a via gap for preventing impedance distortion due to the vertical via  1130 . Referring to  FIG.  14 B , a multi-layer impedance conversion structure including a feeding line and a via is configured to connect one or more of the transmission lines TL 1  and TL 2  located on different layers. The multi-layer impedance conversion structure is configured to further include the vertical via  1130  and layers of the ground G 1 , G 2 , . . . , n adjacent to the vertical via  1130 , the vertical via  1130  being configured to physically connect one of more of the transmission lines TL 1  and TL 2  to each other. 
     When only one transmission line is present, the vertical via  1130  not being connected to the transmission line may be regarded as having only a via pad and a vertical connection part. As an example, the vertical via  1130  having only a via pad and a vertical connection part may be configured as a ground via connected to a ground. Alternatively, the vertical via  1130  may not be impedance converted to a 50 ohm line, and may be configured to be directly connected to any point of an antenna. In relation to this, referring to  FIGS.  8  and  14 B , the vertical via  1130  may not be connected to the second transmission line TL 2 , but may be directly connected to the lower antenna  1100 L. 
     Referring to  FIGS.  8  and  14 B , the via pads VP 1 , VP 2 , . . . , VPn may be spaced apart from the ground G 1 , G 2 , . . . , Gn arranged on same layers, respectively, by a same gap interval. On the other hand, referring to  FIGS.  8  and  14 B , the via pads VP 1 , VP 2 , . . . , VPn may be arranged on same layers as the ground G 1 , G 2 , . . . , Gn, respectively, to have gaps with certain different widths therebetween. 
     Referring to  FIG.  14 B , like a modified embodiment of the via clearance, an impedance may be adjusted by providing gap intervals in respective layers, i.e., GA 1  and GA 2  to have different sizes. GA 1  denotes a via gap between each of the transmission lines TL 1  and TL 2  and a ground. On the other hand, GA 2  denotes a via gap between the ground and the vertical via  1130  arranged in a vertical region between the transmission lines TL 1  and TL 2 . A plurality of the via gaps GA 1  and GA 2  present in the respective layers may be different from each other. As an example, a relationship between the via gaps GA 1  and GA 2  may be set as being GA 1 &lt;GA 2 , but is not limited thereto. 
     As described above, a gap between layers on which the first and second transmission lines TL 1  and TL 2  are arranged may be configured as the via gap GA 1 , and a gap interval in the multi-layer substrate may be configured to increase in the via gap GA 2 . Accordingly, ground layers may be arranged horizontally adjacent to the vertical via  1130  above and below the second transmission line TL 2  to provide a strip line over a whole length in a horizontal direction. However, gap intervals having different certain widths are not limited to the configuration of  FIG.  14 B . 
     As another example, a gap between layers on which the first and second transmission lines TL 1  and TL 2  are arranged may be configured as the via gap GA 2 , and a gap interval in the multi-layer substrate may be configured to further decrease in the via gap GA 1 . Accordingly, a characteristic impedance of the vertical via  1130  may be configured to decrease in the multi-layer substrate, and increase in an upper or lower portion of the multi-layer substrate. 
     GA 3  denotes a via gap interval provided in opposite sides of the via gaps GA 1  and GA 2  with reference to the vertical via  1130 . Impedance control performance may be enhanced by providing an asymmetric structure by adjusting a value of GA 3  to be different from values of GA 1  and GA 2 . 
     A via gap modification design structure of  FIG.  14 B  may be used with a λ/4 conversion device structure according to the various embodiments of  FIGS.  12 A to  12 C . Referring to  FIGS.  8 ,  9 ,  12 A to  12 C, and  14 B , the via pads VP 1 , VP 2 , . . . , VPn may be arranged on different layers, and arranged on same layers as layers of the ground G 1 , G 2 , . . . , Gn, respectively, to have gaps with certain different widths therebetween. In relation to this, at least one of the first impedance transformer  1120   a  and the second impedance transformer  1120   b  may be implemented to have a line width of 50 ohms. Accordingly, a length of a transmission line may be reduced by implementing at least one of the first and second transmission lines TL 1  and TL 2  without an impedance transformer. Accordingly, in a high frequency band such as a mmWave band, a line loss in the transmission line may be minimized. 
     Electrical characteristics of the multi-layer impedance conversion structure described herein are as described below. In relation to this,  FIG.  15 A  illustrates impedance changes in a first structure and a second structure on a Smith chart, the first structure including feeding lines connected to each other through a vertical via and the second structure including a multi-layer impedance transformer.  FIG.  15 B  illustrates a reflection loss and a transmission loss according to frequency changes in the first and second structures of  FIG.  15 A . 
     With respect to  FIG.  15 A , the first structure is a structure in which the first and second transmission lines TL 1  and TL 2  are connected to each other by the vertical via  1130  without an impedance transformer, as shown in  FIG.  12 A , On the other hand, the second structure is a structure in which the first and second transmission lines TL 1  and TL 2  are connected to each other by the first and second impedance transformers  1121  and  1122  to have the vertical via  1130  therebetween, as shown in  FIG.  12 C . 
     Referring to  FIGS.  12 A,  12 C, and  15 A , an impedance characteristic of the first structure is significantly spaced apart from a center corresponding to  50  ohms, as shown in the Smith chart. The first structure is a structure in which only a feeding line including the first and second transmission lines TL 1  and TL 2 , and the vertical via  1130  are present. On the other hand, an impedance characteristic of the second structure is arranged at the center corresponding to 50 ohms, and a change according to a frequency change is small. The second structure is a structure in which the first and second transmission lines TL 1  and TL 2  are connected to each other by the first and second impedance transformers  1121  and  1122  having different line widths with reference to the vertical via  1130 . 
     (a) of  FIG.  15 B  illustrates a reflection loss according to frequency changes in the first and second structures of  FIG.  15 A . (i) In the first structure of (a) of  FIG.  15 B , a reflection loss for each frequency has a value equal to or less than −10 dB, and equal to or greater than - 15  dB. On the other hand, (ii) in the second structure of (a) of  FIG.  15 B , a reflection loss for each frequency has a value of −20 dB or less in a band from 57 to 70 GHz. Accordingly, in a case of a reflection loss corresponding to S 11 , when the multi-layer impedance conversion structure described herein is used, an effect of performance improvement by about 10 dB or greater in the band of 57 to 70 GHz may be obtained. 
     (b) of  FIG.  15 B  illustrates a transmission loss according to frequency changes in the first and second structures of  FIG.  15 A . (i) In the first structure of (b) of  FIG.  15 B , a transmission loss for each frequency has a value equal to or greater than −0.5 dB. On the other hand, (ii) in the second structure of (b) of  FIG.  15 B , a transmission loss for each frequency has a value of about 0.2 in the band from 57 to 70 GHz. Accordingly, when the multi-layer impedance conversion structure described herein is used, a performance improvement effect such that a transmission loss corresponding to S 21  in the band from 57 to 70 GHz is reduced by a half or more may be obtained. 
     The multi-layer impedance conversion structure described herein may be configured such that a plurality of ports of the RFIC are connected to a plurality of antenna elements. In relation to this,  FIG.  16 A  illustrates a configuration in which the ports of the RFIC are connected to the antenna devices.  FIG.  16 B  is a side view illustrating the RFIC connected to the plurality of antenna devices on a multi-layer substrate. 
     Referring to  FIGS.  16 A and  16 B , in the array antennas  1100   a  and  1100   b , a line length of the first antenna  1100   a  far apart from the RFIC  1250  is different from a line length of the second antenna  1100   b  close to the RFIC  1250 . In this case, a length La of the first microstrip line of the first antenna  1100   a  may be greater than a length Lb of a microstrip line of the second antenna  1100   b . The first antenna  1100   a  and the second antenna  1100   b  of  FIG.  16    are illustrated as side antennas, but are not limited thereto. A configuration for adjusting a line length may be applied to the lower antenna or the upper antenna. 
     Since the first antenna  1100   a  has a whole line length greater than that of the second antenna  1100   b , the length La of the first microstrip line of the first antenna  1100   a  may be configured to be greater to minimize a phase difference between signals applied to the first antenna  1100   a  and the second antenna  1100   b . Accordingly, a line loss in the whole line of the first antenna  1100   a  may be reduced, and a phase difference from the second antenna  1100   b  may be reduced. In relation to this, since an upper region of the microstrip line is exposed to air, an effective permittivity is lower compared to that of a structure in which a dielectric is arranged in the upper and lower portions. Accordingly, an electrical length of an RF signal proceeding through a feeding line implemented as a microstrip line is shorter than an electrical length of an RF signal proceeding through a feeding line implemented as a strip line. Accordingly, an electrical length difference between the first antenna  1100   a  and the second antenna  1100   b  may be reduced, compared to a physical length difference therebetween. 
     With respect to the above-described technical configurations, the antenna module  1100  may be configured to include the first antenna  1100   a  and the second antenna  1100   b  arranged further apart from the transceiver circuit  1250  than the first antenna  1100   a . The transceiver circuit  1250  is connected to the first antenna  1100   a  through a first microstrip line MSL 1  and a first strip line SL 1 . In addition, the transceiver circuit  1250  is connected to the second antenna  1100   b  through a second microstrip line MSL 2  and a second strip line SL 2 . 
     In relation to this, a length of the second microstrip line MSL 2  may be greater than a length of the first microstrip line MSL 1 . Accordingly, a difference between a length from the transceiver circuit  1250  to the first antenna  1110   a  and a length from the transceiver circuit  1250  to the second antenna  1110   b  may be compensated for. Accordingly, an electrical length difference between the first antenna  1100   a  and the second antenna  1100   b  may be reduced, compared to a physical length difference therebetween. 
     The first antenna  1100   a  and the second antenna  1100   b  may refer to different antenna elements in the array antenna. As another example, the first antenna  1100   a  and the second antenna  1100   b  may refer to different antenna elements constituting different array antennas, respectively. The electronic device may be configured to perform beamforming through an array antenna, as illustrated in  FIG.  3 B . The electronic device may use a plurality of array antennas to communicate with a plurality of electronic devices or perform MIMO as illustrated in  FIGS.  4  and  6   . 
     As an example, the first antenna  1100   a  and the second antenna  1100   b  configured as different antenna elements in an array antenna may partially compensate for a physical distance difference therebetween with reference to the RFIC  1250  by adjusting lengths of the microstrip lines to be different from each other. 
     Even when the physical distance difference is compensated for by adjusting the lengths of the microstrip lines to be different from each other, an electrical length difference therebetween with reference to the RFIC  1250 , i.e., a phase difference may still occur. To compensate for this phase difference, phase values of phase shifters in the antennas  1100   a  and  1100   b  may be adjusted to control phases of signals applied to the antennas  1100   a  and  1100   b  to be equal to each other, respectively. 
     The upper antenna  1100 U, the lower antenna  1100 L, or the side antenna  1100 S of  FIG.  8    disclosed herein may be configured as array antennas. By adjusting phases of the signals applied to the respective array antennas to be same, a beam may be oriented toward a center direction. In relation to this, a direction of the beam oriented toward the center direction may be a direction toward a first beam B 1  or a second beam B 2  as illustrated in  FIG.  18   . 
     On the other hand, beam forming may be performed so that the beam direction is tilted from the center direction to a predetermined direction by adjusting phases of signals applied to each element of the respective array antennas to be different from each other. To do so, the transceiver circuit  1250  may control the phase shifter to vary the phases of the signals applied to each antenna element. Accordingly, a direction of a beam-formed signal may be changed in correspondence with a certain angle from a direction of the first beam B 1  to a direction of the second beam B 2  both shown in  FIG.  18   . Accordingly, as illustrated in  FIG.  3 B , beamforming may be performed so that each electronic device radiates a signal in an optimal direction. 
     The side antenna  1100 S or the lower antenna  1100 L, each disclosed herein as having a multi-layer impedance structure, may be configured as an array antenna. In relation to this,  FIG.  17 A  illustrates a structure in which the antenna module  1100  including a first type antenna and a second type antenna provided as an array antenna is arranged in an electronic device  1000 .  FIG.  17 B  is a magnified view of a plurality of array antenna modules. 
     Referring to  FIGS.  1  to  17 B , an array antenna may include a first array antenna module  1100 - 1  and a second array antenna module  1100 - 2  arranged apart from the first array antenna module  1100 - 1  by a certain distance in a first horizontal direction. Array antenna modules are not limited to two array antenna modules. Three or more array antenna modules may be implemented as illustrated in  FIG.  17 B . Accordingly, the array antenna may be configured to include first to third array antenna modules  1100 - 1  to  1100 - 3 . As an example, at least one of the first to third array antenna module  1100 - 1  to  1100 - 3  may be arranged on a side surface of the antenna module  1100  and configured to provide a beam in a side direction B 3 . 
     As another example, at least one of the first array antenna module  1100 - 1  and the third array antenna module  1100 - 3  may be arranged on a front surface of the antenna module  1100  and configured to provide a beam in a front direction B 1 . In relation to this, first and second beams may be provided in the front direction B 1  using the first array antenna module  1100 - 1  and the second array antenna module  1100 - 2 , respectively. The processor  1400  corresponding to the modem of  FIG.  5 C  may control to provide the first beam and the second beam in the first direction and the second direction using the first and second array antenna modules  1100 - 1  and  1100 - 2 , respectively. That is, the processor  1400  may provide the first beam from a horizontal direction to the first direction using the first array antenna module  1100 - 1 . In addition, the processor  1400  may provide the second beam from the horizontal direction to the second direction using the second array antenna module  1100 - 2 . In relation to this, the processor  1400  may perform MIMO using the first beam in the first direction and the second beam in the second direction. 
     The processor  1400  may provide a third beam in a third direction using the first and second array antenna modules  1100 - 1  and  1100 - 2 . In relation to this, the processor  1400  may control the transceiver circuit  1250  to synthesize signals received through the first and second array antenna modules  1100 - 1  and  1100 - 2 . Also, the processor  1400  may control the signals transmitted to the first and second array antenna modules  1100 - 1  and  1100 - 2  through the transceiver circuit  1250  to be distributed to each antenna element. The processor  1400  may perform beamforming using a third beam having a beam width smaller than beam widths of the first beam and the second beam. 
     The processor  1400  may perform MIMO using the first beam in the first direction and the second beam in the second direction, and perform beamforming using the third beam having a beam width smaller than beam widths of the first and second beams. In relation to this, when quality of the first signal and the second signal received from another electronic device in a periphery of the electronic device is equal to or less than a threshold, beamforming may be performed using the third beam. 
     A number of elements of the array antenna is not limited to two, three, four, or the like as illustrated in the drawing. For example, the number of the elements of the array antenna may extend to 4, 8, 16, or the like. Accordingly, the array antenna may be configured as a 1×2, 1×3, 1×4, 1×5, or 1×8 array antenna. 
       FIG.  18    illustrates antenna modules combined to have different combination structures at a particular position in the electronic device. Referring to (a) of  FIG.  18   , the antenna module  1100  may be arranged in a lower region of a display  151  to be substantially horizontal with the display  151 . Accordingly, the beam B 1  may be generated in a downward direction of the electronic device through a monopole radiator. Another beam, i.e., the second beam B 2  may be generated in a front direction of the electronic device through a patch antenna. 
     Referring to (b) of  FIG.  18   , the antenna module  1100  may be arranged in a lower region of the display  151  to be substantially vertical to the display  151 . Accordingly, the beam B 2  may be generated in a front direction of the electronic device through the monopole radiator. Another beam B 1 , i.e., the first beam B 1  may be generated in a downward direction of the electronic device through the patch antenna. 
     Referring to (c) of  FIG.  18   , the antenna module  1100  may be arranged in a rear case  1001  corresponding to a mechanical structure. The antenna module  1100  may be arranged substantially parallel to the display  151  in the rear case  1001 . Accordingly, the beam B 2  may be generated in a downward direction of the electronic device through a monopole radiator. Another beam, i.e., a third beam B 3  may be generated in a rear direction of the electronic device through the patch antenna. 
     An electronic device equipped with an antenna module having a multi-layer impedance conversion structure according to an aspect of the present specification has been described above. Hereinafter, an antenna module having a multi-layer impedance conversion structure according to another aspect of the present specification is described with reference to  FIGS.  1  to  18   . 
     The antenna module  1100  disclosed herein includes an antenna element operating in a  60  GHz band, such as a patch radiator, a monopole radiator, or a dipole radiator, that is, any radiator radiating in an upper/lower direction or a side direction of the multi-layer substrate. The antenna module  1100  may include an antenna element and the first and second transmission lines  1120   a  and  1120   b  connecting the RFIC  1250  to the antenna element. A frequency band of a signal radiated through the antenna element and a signal transmitted through the first and second transmission lines  1120   a  and  1120   b  may be changed according to applications. 
     In relation to this, in the mmWave band (e.g., 10 GHz to 300 GHz), an antenna and an RFIC arranged on different layers of a multi-layer board corresponding to a PCB need to be connected to each other through a transmission line. In addition, the present specification is to provide a structure of a transmission line connecting feeding lines on different layers of a multi-layer substrate to each other. For example, the antenna module  1100  may be configured to have a bandwidth (BW) of 13 GHz or higher in a 60 GHz band. This is because, in a case of the IEEE 802.11ay, the use frequency band has a wide bandwidth of 57 to 70 GHz. 
     To achieve this purpose, the antenna module having a multi-layer impedance conversion structure described herein may achieve the above-mentioned purpose by performing the solutions described below. The antenna module  1100  of  FIGS.  1  to  18    disclosed herein may be an integral type. As an example, a transmission line is implemented using vias and via pads used in a PCB process, and an antenna is placed on an upper portion, a lower portion or a side portion of the PCB such that antenna elements are provided integrally with the PCB that is the multi-layered substrate. 
     The antenna module disclosed herein is configured to include the first transmission line TL 1  or  1120   a , the second transmission line TL 2  or  1120   b , and the vertical via  1130 . The first transmission line TL 1  or  1120   a  may be arranged on a first layer of the antenna module  1100  and configured to be electrically connected to the transceiver circuit  1250 . The second transmission line TL 2  or  1120   b  may be arranged on a second layer of the antenna module  1100  and configured to be electrically connected to the antenna  1100 U,  1100 S, or  1100 L. The vertical via  1130  may be configured to vertically connect the first transmission line TL 1  or  1120   a  to the second transmission line TL 2  or  1120   b.    
     The first impedance transformer  1121  of the first transmission line TL 1  or  1120   a  connected to the vertical via  1130  may be configured to have a first width W 1  and the first length L 1 . The second impedance transformer  1122  of the second transmission line TL 2  or  1120   b  connected to the vertical via  1130  may be configured to have the second width W 2  and the second length L 2 . 
     Widths and lengths of the first and second impedance transformers  1121  and  1122  including the microstrip line and the strip line having a multi-layer impedance structure of the antenna module  1100  may be configured within a certain range. Accordingly, electrical performance in the mmWave band may be maintained to minimize a line loss while maintaining bandwidth characteristics of the multi-layer impedance structure. 
     In relation to this, the first transmission line TL 1  or  1120   a  may be is configured as a microstrip line in which an air layer is provided without a dielectric on a conductive line arranged on a dielectric. The second transmission line TL 2  or  1120   b  may be configured as a strip line in which dielectrics are arranged on and below a conductive line, respectively. 
     The ratio L 1 /L 2  of the first length L 1  of the first impedance transformer  1121  to the second length L 2  of the second impedance transformer  1122  may be set to be within a range from 0.45 to 1.35. In addition, the ratio W 1 /W 2  of the first width W 1  of the first impedance transformer  1121  to the second width W 2  of the second impedance transformer  1122  may be set to within a range from 0.32 to 0.71. 
     An antenna module having a multi-layer impedance conversion structure operating in a millimeter wave band and an electronic device including the antenna module have been described above. Technical effects of the antenna module having the multi-layer impedance conversion structure operating in a millimeter wave band and the electronic device including the antenna module are described below. 
     Technical effects of the antenna module having the multi-layer impedance conversion structure operating in a millimeter wave band and the electronic device including the same are described below. 
     According to an embodiment, an antenna module in which all feeding lines may be arranged using a small number of layers in a space where it is difficult to arrange all the feeding lines may be provided. 
     According to an embodiment, a feeding line is connected, along minimized detour paths, to all antennas in the mmWave antenna module having an extended coverage to thereby minimize a line loss. 
     According to an embodiment, both performance of a transmission loss S 11  and performance of a transmission loss S 21  may be enhanced through impedance matching of feeding lines in a broadband of the millimeter wave band. 
     According to an embodiment, impedance matching characteristics of an antenna element electrically connected to a feeding line inside a multi-layered board type PCB may be enhanced by configuring different types of impedance transformers with reference to vertical vias. 
     According to an embodiment, transmission lines including a microstrip line and a strip line are connected to each other via a vertical via and an impedance transformer is provided on at least one side to thereby minimize a line loss while performing impedance matching. 
     According to an embodiment, by adjusting a gap interval between a vertical via and an adjacent ground, the vertical via connecting transmission lines on different layers to each other, a line loss may be minimized while impedance matching is performed. 
     Further scope of applicability of the present disclosure will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, such as the preferred embodiment of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art. In relation to the aforementioned disclosure, design and operations of an antenna operating in a mmWave band and an electronic device controlling the same can be implemented as computer-readable codes in a program-recorded medium. 
     The computer-readable medium may include all types of recording devices each storing data readable by a computer system. Examples of such computer-readable media may include hard disk drive (HDD), solid state disk (SSD), silicon disk drive (SDD), ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage element and the like. Also, the computer-readable medium may also be implemented as a format of carrier wave (e.g., transmission via an Internet). The computer may include the controller of the terminal. Therefore, the detailed description should not be limitedly construed in all of the aspects, and should be understood to be illustrative. Therefore, all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.