Patent Publication Number: US-2023163487-A1

Title: Slot antennas with bridge portions

Description:
BACKGROUND 
     Portable electronic devices are becoming increasingly popular. Examples of portable electronic devices may include handheld computers (e.g., notebooks, tablets, and the like), cellular telephones, media players, and hybrid devices which include the functionality of multiple devices of this type. Due in part to their mobile nature, such electronic devices may often be provided with wireless communications capabilities, which may rely on antenna technology to radiate radio frequency (RF) signals for transmission as well as to gather RF broadcast signals for reception. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Examples are described in the following detailed description and in reference to the drawings, in which: 
         FIG.  1 A  is a schematic diagram of an example electronic device, including an antenna layout disposed across a first slot, a second slot, and a bridge portion; 
         FIG.  1 B  is a schematic diagram of the example electronic device of  FIG.  1 A , depicting additional features; 
         FIG.  2    is a schematic diagram of another example electronic device, depicting an antenna trace disposed on a printed circuit board (PCB) and extended from a first slot to a second slot via a bridge portion; 
         FIG.  3 A  is a cross-sectional front view of a portion of the example electronic device of  FIG.  2   , depicting additional features; 
         FIG.  3 B  is a cross-sectional side view of the example electronic device of  FIG.  2   , depicting a microstrip line structure; 
         FIG.  3 C  is another cross-sectional side view of the example electronic device of  FIG.  2   , depicting the first slot under the antenna trace. 
         FIG.  4 A  is a schematic diagram of an example electronic device, depicting a PCB antenna to couple an electromagnetic energy to a first closed slot, a second closed slot, and a bridge portion; and 
         FIG.  4 B  is a schematic diagram of the example electronic device of  FIG.  4 A , depicting additional features. 
     
    
    
     DETAILED DESCRIPTION 
     As mobile computing infrastructure evolves to enable electronic devices to transmit and receive significant amount of data while on the move, the abilities of the electronic devices to receive and transmit various signals simultaneously increase in demand. For example, the electronic devices may be notebooks, tablets, cellular telephones, media players, and hybrid devices which include the functionality of multiple devices of this type. Further, the electronic devices may employ radio devices for communication via wireless links operating on a variety of radio access technologies. For example, an electronic device may employ a radio device for wireless local area network (WLAN) signals, or the like. Example WLAN signals may include wireless links adhering to standards such as, for example, wireless fidelity (Wi-Fi), wireless gigabit alliance (WiGig), and/or wireless personal area network (WPAN). In other examples, several radio devices may be available for each radio access technology to enable aggregated data communications such as via plural multiple in, multiple out (MIMO) streams to enhance bandwidth or reliability. 
     Such electronic devices may include antennas to communicate with the wireless network. An antenna may be a device that emits or receives radio waves. The antenna may be used with a transmitter of a radio device. The transmitter may generate a radio signal, which may be an alternating current. The antenna may emit the radio signal as electromagnetic energy termed radio waves. The antenna may also be used with a receiver of the radio device. The receiver may receive a radio signal from the antenna and convert the information carried by the radio signal into a usable form. The radio device including both the transmitter and the receiver may be termed as a transceiver. For example, the electronic device may include a WLAN antenna to communicate with a local area network (LAN), or the like. Other example antennas may include a WWAN antenna to communicate with a wide area network (WAN), cellular antennas, wireless fidelity (Wi-Fi) antennas, Bluetooth antennas, global navigation satellite system (GNSS) antennas, and/or near field communication (NFC) antennas. 
     Such electronic devices may be provided with a conductive housing (e.g., a rear housing that houses a display panel). The conductive housing may be formed from a metal. In such electronic devices, the presence of the conductive housing can influence the antenna performance. The antenna performance may be degraded when the conductive housing interferes with the antenna operation. To reduce the interference, the antennas for the electronic devices may be formed as slot antennas. 
     A slot antenna may be formed from portions of the conductive housing. In an example, the slot antenna is formed from a slot in the conductive housing. For example, the slot antenna is formed from a closed slot and an antenna structure (e.g., a printed circuit board (PCB) with an antenna trace, a dielectric material with a conductive pattern, or the like) of the electronic device. Such antennas can be used for the WLAN communications. 
     Further, a width of the slot may have an impact on the performance of the slot antenna. For example, consider that a closed loop slot antenna is disposed in the electronic device. The closed loop slot antenna may be formed by a closed slot in the conductive housing of the electronic device. In this example, the slot, which is a non-metal area, is defined for radiation of the antenna. The slot may have a dimension of around half wavelength to quarter wavelength of an application frequency. In such a scenario, the antenna radiation performance may be around 50% when a width of the slot is around 2.5 mm for the 2.4 GHz, 5 GHz, and 6 GHz applications (e.g., designed for WiFi, WiFi 6E, or the like applications) without considering an insertion loss of a coaxial cable (e.g., which connects to the slot antenna via an antenna feed). In this example, the antenna structure may be defined as an “antenna feed” and an “antenna ground”. The “antenna feed” and the “antenna ground” may be disposed on the PCB. Thus, a length of the PCB may be similar to a length of the slot. 
     In such scenarios, the length of the slot may have an impact on a center frequency and a width of the slot may have an impact on the antenna performance. For example, the performance of the antenna may be reduced when the slot width is reduced below 2.5 mm. Therefore, the electronic devices may define a slot width of about 2.5 mm on the conductive housing, for instance, for WLAN applications to meet a target performance. However, the slot width of around 2.5 mm may be visible on the laptop computer and may affect a physical appearance of the electronic device. For an industrial point of view, a minimum or reduced slot width may enhance an appearance of the electronic device. 
     Examples described herein provides an electronic device including a conductive housing (e.g., a metal housing). The conductive housing may include a first slot, a second slot, and a bridge portion (e.g., a conductive line) to separate the first slot and the second slot. Further, the electronic device may include a PCB disposed on the conductive housing via a first surface of the PCB, Furthermore, the electronic device may include an antenna trace formed on a second surface of the PCB. The antenna trace may extend from the first slot to the second slot via the bridge portion. Also, the electronic device may include an antenna feed electrically connected to the antenna trace in the first slot and an antenna ground electrically connected to the antenna trace in the second slot. 
     The first slot and the second slot may have a combined length of around one wavelength of the application frequency. In this example, the bridge portion facilitates the first slot and the second slot to resonate at different resonant frequencies of a frequency band. Examples described herein reduces the slot width, for instance, from about 2.5 mm to about 1 mm (e.g., which is about 70% size reduction of the slot width) with the antenna radiation efficiency of about 50%. Thus, examples described herein enhances the appearance of the electronic devices. 
     In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present techniques. However, the example apparatuses, devices, and systems, may be practiced without these specific details. Reference in the specification to “an example” or similar language means that a particular feature, structure, or characteristic described may be included in at least that one example but may not be in other examples. 
     Turning now to the figures,  FIG.  1 A  is a schematic diagram of an example electronic device  100 , including an antenna layout  110  disposed across a first slot  104 , a second slot  106 , and a bridge portion  108 . Example electronic device  100  is a laptop computer, a notebook computer, a tablet computer, a smartphone, or the like. As shown in  FIG.  1 A , electronic device  100  includes conductive housing  102 . Conductive housing  102  may be formed from a metal such as an aluminum alloy, a magnesium alloy, zinc alloy, or the like. Example conductive housing  102  is a display housing (e.g., a rear housing) to house a display panel. 
     In an example, conductive housing  102  includes first slot  104 , second slot  106 , and bridge portion  108  to separate first slot  104  and second slot  106 . As used herein, bridge portion  108  is a conductive structure that divides an elongated opening in conductive housing  102  into first slot  104  and second slot  106 . Bridge portion  108  is formed between a short side of first slot  104  and second slot  106 . In an example, bridge portion  108  is formed as a single-piece structure with conductive housing  102  between first slot  104  and second slot  106 . In this example, first slot  104  is etched on conductive housing  102 . Further, second slot  106  is etched on conductive housing  102  adjacent to first slot  104  and is separated from first slot  104  by bridge portion  108  etched in between first slot  104  and second slot  106 . In another example, bridge portion  108  is electrically connected to conductive housing  102  across the elongated opening to divide the elongated opening into first slot  104  and second slot  106 . Bridge portion  108  may isolate first slot  104  and second slot  106  to prevent any interference of signals communicated via first slot  104  and second slot  106 . 
     In some examples, conductive housing  102  includes a display region and a non-display region. The non-display region may be covered by a bezel of conductive housing  102  or a display layer (e.g., a front glass) of the display panel. In this example, first slot  104 , second slot  106 , and bridge portion  108  is formed in an upper non-display region that abuts a top side of the display region as shown in  FIG.  1 A . In another example, first slot  104 , second slot  106 , and bridge portion  108  can be formed in a lower non-display region that abuts a bottom side of the display region. In other examples, first slot  104 , second slot  106 , and bridge portion  108  can also be formed in the display region behind the display panel. 
     Further, electronic device  100  includes antenna layout  110  disposed across first slot  104 , second slot  106 , and bridge portion  108  as shown in  FIG.  1 A . In this example, first slot  104 , second slot  106 , and antenna layout  110  may form a slot antenna. The slot antenna may emit or receive radio waves. Antenna layout  110  may be used with a transmitter/receiver of a radio device. The radio device including both the transmitter and the receiver may be termed as a transceiver. Antenna resonating elements for antenna layout  110  may be formed from first slot  104  and second slot  106  in conductive housing  102 . First slot  104  and second slot  106  may be filled with air or with a solid dielectric such as plastic, epoxy, or the like. Each of the first slot  104  and second slot  106  may have a length that is longer than a width. First slot  104  and second slot  106  may serve as antenna resonating elements for antenna layout  110 , and conductive housing  102  may serve as a ground plane for antenna layout  110 . 
     In an example, antenna layout  110  includes a dielectric layer and an antenna layer (e.g., a conductive material). In this example, bridge portion  108 , a portion of the dielectric layer below bridge portion  108 , and a portion of the antenna layer below bridge portion  108  are to operate as a microstrip line. As used herein, the microstrip line is an electrical transmission line which can be fabricated with a technology where a conductor (e.g., the antenna layer) is separated from a ground plane (e.g., bridge portion  108 ) by the dielectric layer. The microstrip line can be used to convey microwave-frequency signals. A characteristic impedance of the microstrip line is a function of a width and a thickness of the conductor and a distance between the conductor and bridge portion  108 . 
     In an example, first slot  104  and second slot  106  are closed slots. Further, bridge portion  108  may have a width in a range of 2 mm to 10 mm between first slot  104  and second slot  106 , for instance, in 2.4 GHz, 5 GHz, and 6 GHz frequency bands. Bridge portion  108  may be made up of a metal as that of conductive housing  102 , for instance. 
     Further, electronic device  100  includes an antenna feed  112  and an antenna ground  114 . In an example, antenna feed  112  is coupled to antenna layout  110  in first slot  104  and antenna ground  114  is coupled to antenna layout  110  in second slot  106 . For example, antenna feed  112  is to supply a radio frequency input from a feedline (e.g., a coaxial cable). Antenna feed  112  may be a location on antenna layout  110 , where the feedline from antenna feed  112  is connected. As used herein, the feedline is a transmission line connected between antenna layout  110  and the transceiver. During operation, antenna feed  112  may convey radio-frequency signals between antenna layout  110  and the transceiver. 
     Antenna ground  114  may be a location on antenna layout  110 , where antenna layout  110  is connected to a grounding element. The grounding element may be a flat horizontal conducting surface that serves as part of antenna layout  110 , to reflect the radio waves from the other antenna elements. An example grounding element is formed from a printed circuit board (PCB), a planar metal structure, conductive electrical components, conductive housing  102 , or any combination thereof. 
     During operation, antenna layout  110  may couple electromagnetic energy to first slot  104 , second slot  106 , and bridge portion  108 . In this example, first slot  104  resonates at a first resonant frequency in a frequency band and second slot  106  resonates at a second resonant frequency in the frequency band. The second resonant frequency is different from the first resonant frequency. Further, the first slot and the second slot may include a combined length of about one wavelength of a frequency in a frequency band of interest to meet a target performance. 
       FIG.  1 B  is a schematic diagram of example electronic device  100  of  FIG.  1 A , depicting additional features. For example, similarly named elements of  FIG.  1 B  may be similar in structure and/or function to elements described with respect to  FIG.  1 A . Particularly,  FIG.  1 B  depicts a rear view of electronic device  100  of  FIG.  1 A . As shown in  FIG.  1 B , electronic device  100  includes a non-conductive cover portion  152  to cover or fill first slot  104  and second slot  106  of  FIG.  1 A . Non-conductive cover portion  152  may be formed using a material such as rubber, plastic, or the like. First slot  104  and second slot  106  may have a width  154  of about 1 mm, for instance. Thus, examples described herein may utilize first slot  104 , second slot  106 , and bridge portion  108  to reduce a width of slots for slot antennas without compromising on the antenna efficiency. 
       FIG.  2    is a schematic diagram of another example electronic device  200 , depicting an antenna trace  212  disposed on a PCB  210  and extended from a first slot  204  to a second slot  206  via a bridge portion  208 . As shown in  FIG.  2   , electronic device  200  includes conductive housing  202 . In an example, conductive housing  202  includes first slot  204 , second slot  206 , and bridge portion  208  to separate first slot  204  and second slot  206 . For example, first slot  204  includes a first length and second slot  206  includes a second length different from the first length. The second length may be less than the first length. 
     Further, electronic device  200  incudes PCB  210  disposed on conductive housing  202  via a first surface of PCB  210 . For example, PCB  210  is a laminated sandwich structure of conductive and insulating layers. Furthermore, electronic device  200  includes antenna trace  212  formed on a second surface of PCB  210 . Antenna trace  212  may extend from first slot  204  to second slot  206  via bridge portion  208 . 
     In an example, antenna trace  212  is a surface mount antenna that can be disposed or formed on PCB  210 . In another example, antenna trace  212  is integrated in PCB  210 . In yet another example, antenna trace  212  can be a PCB antenna that includes another PCB and a trace drawn onto the other PCB. Example antenna trace  212  can be a PCB trace antenna, a patch antenna, a chip antenna, a dipole antenna, a monopole antenna, a loop antenna, microstrip antenna, or any other type of antenna suitable for transmission of radio frequency signals. An example PCB trace antenna may include a trace laminated on a surface of PCB  210  or, in some examples, traces that can occupy several layers of a multilayer PCB, and the traces on each layer may be interconnected. 
     Furthermore, electronic device  200  includes an antenna feed  214  electrically connected to antenna trace  212  in first slot  204  and an antenna ground  216  electrically connected to antenna trace  212  in second slot  206 . Bridge portion  208 , a portion of PCB  210  below bridge portion  208 , and a portion of antenna trace  212  below bridge portion  208  may form a microstrip line to provide mutual electrical field of conductive housing  202  to antenna trace  212 . In an example, bridge portion  208  controls an impedance of antenna trace  212 . The impedance may relate to a voltage and current at an input to antenna trace  212 . 
       FIG.  3 A  is a cross-sectional front view (e.g., S 1  as shown in  FIG.  2   ) of a portion of example electronic device  200  of  FIG.  2   , depicting additional features. For example, similarly named elements of  FIG.  3 A  may be similar in structure and/or function to elements described with respect to  FIG.  2   . As shown in  FIG.  3 A , antenna trace  212  is disposed in three different areas (e.g., A, B, and C). For example, area “A” (e.g., corresponding to first slot  204 ) includes a first part of antenna trace  212  and an antenna feed (i.e., antenna feed  214  as shown in  FIG.  2   ). Further, area “B” (e.g., corresponding to bridge portion  208 ) may include a second part of antenna trace  212 . The second part of antenna trace  212 , medium from PCB  210 , and bridge portion  208  in area B may provide a microstrip line structure. Further, a width  302  of bridge portion  208  may facilitate in current phase and impedance adjustment as described in  FIGS.  3 B and  3 C . 
     Furthermore, area “C” (e.g., corresponding to second slot  206 ) may include a third part of antenna layout  212 . Antenna layout  212  may be short to the ground in area “C”. Thus, antenna trace  212  continues from area “A” to area “C” by a conductive material. Antenna trace  212  may include three different couplings. For example, antenna trace  212  couples an electromagnetic energy to first slot  204  in area “A”, to bridge portion  208  in area “B”, and to second slot  206  in area “C”. 
       FIG.  3 B  is a cross-sectional side view (e.g., S 2  as shown in  FIG.  2   ) of example electronic device  200  of  FIG.  2   , depicting a microstrip line structure. In the example shown in  FIG.  3 B , a part of antenna trace  212 , PCB  210 , and bridge portion  208  may work as the microstrip line structure to provide a mutual electrical field of conductive housing  202  to antenna trace  212 . Further, a distance between antenna trace  212  and bridge portion  208 , a shape of antenna trace  212  below bridge portion  208 , and a material between bridge portion  208  and antenna trace  212  are to define a mutual electric field and an impedance of antenna trace  212 . 
       FIG.  3 C  is another cross-sectional side view (e.g., S 3  as shown in  FIG.  2   ) of example electronic device  200  of  FIG.  2   , depicting first slot  204  under antenna trace  212 . In the example shown in  FIG.  3 C , first slot  204  is under antenna trace  212  and passes electric field through first slot  204 . Similarly, second slot  206  may be under antenna trace  212  and may pass electric field through second slot  206 . 
       FIG.  4 A  is a schematic diagram of an example electronic device  400 , depicting a PCB antenna  408  to couple an electromagnetic energy to a first closed slot  412 , a second closed slot  414 , and a bridge portion  416 . As shown in  FIG.  4 A , electronic device  400  includes a conductive housing  402  that forms a ground plane. Further, electronic device  400  includes a display panel  406  disposed in conductive housing  402 . Furthermore, electronic device  400  includes PCB antenna  408  abutting a side of display panel  406 . Also, electronic device  400  includes first closed slot  412  in conductive housing  402  that forms a first slot antenna resonating element for PCB antenna  408 . Further, electronic device  400  includes second closed slot  414  in conductive housing  402  that forms a second slot antenna resonating element for PCB antenna  408 . 
     Further, electronic device  400  includes bridge portion  416  of conductive housing  402  to separate first closed slot  412  and second closed slot  414 . For example, first closed slot  412  and second closed slot  414  are rectangular slots. First closed slot  412  is defined in series to second closed slot  414 . In this example, bridge portion  416  of conductive housing  402  is formed between a short side of first closed slot  412  and second closed slot  414 . Further, first closed slot  412  may include a length in a range of 45 mm to 60 mm, second closed slot  414  may include a length in a range of 25 mm to 40 mm, and bridge portion  416  may include a width in a range of 2 mm to 10 mm for 2.4 GHz, 5 GHz, and 6 GHz applications. In an example, PCB antenna  408  is to couple an electromagnetic energy to first closed slot  412 , second closed slot  414 , and bridge portion  416 . 
     Further as shown in  FIG.  4 A , electronic device  400  includes an antenna feed  418  to couple the first slot antenna resonating element to a transceiver  410 . Furthermore, electronic device  400  includes an antenna ground  404  to ground the second slot antenna resonating element. In an example, the first slot antenna resonating element in combination with bridge portion  416  is to resonate at a first resonant frequency in a frequency band and the second slot antenna resonating element in combination with bridge portion  416  is to resonate at a second resonant frequency in the frequency band. The second resonant frequency may be different from the first resonant frequency. 
       FIG.  4 B  is a schematic diagram of example electronic device  400  of  FIG.  4 A , depicting additional features. For example, similarly named elements of  FIG.  4 B  may be similar in structure and/or function to elements described with respect to  FIG.  4 A . As shown in  FIG.  4 B , electronic device  400  may include a base housing  460  and conductive housing  402  (i.e., a display housing) detachably, rotatably, or twistably connected to base housing  460 . Base housing  460  may house a keyboard, a battery, a touchpad, and the like, and conductive housing  402  may house display panel  406 . In other examples, conductive housing  402  and base housing  460  may house other components depending on the functions of electronic device  400 . 
     Further, PCB antenna  408  includes a PCB  452  having a first surface and a second surface. PCB  452  may be disposed on conductive housing  402  via the first surface. Further, PCB antenna  408  includes an antenna trace  454  formed on the second surface of PCB  452 . Further, antenna feed  418  may couple the first slot antenna resonating element to transceiver  410  via a feedline  458  (e.g., a coaxial cable). 
     As shown in  FIG.  4 B , electronic device  400  may include a grounding element  456  coupled to conductive housing  402  to ground the second slot antenna resonating element via antenna ground  404 . For example, grounding element  456  is a conductive foil. For example, conductive housing  402  and grounding element  456  are shorted together to form a ground plane in electronic device  400  or to expand a ground plane structure that is formed from a planar circuit structure such as PCB  452  used in forming antenna structures for electronic device  400 . In an example shown in  FIGS.  4 A and  4 B , bridge portion  416 , a portion of PCB  452  below bridge portion  416 , and a portion of antenna trace  454  below bridge portion  416  are to form a microstrip line to provide mutual electrical field of conductive housing  402  to PCB antenna  408 . 
     The above-described examples are for the purpose of illustration. Although the above examples have been described in conjunction with example implementations thereof, numerous modifications may be possible without materially departing from the teachings of the subject matter described herein. Other substitutions, modifications, and changes may be made without departing from the spirit of the subject matter. Also, the features disclosed in this specification (including any accompanying claims, abstract, and drawings), and/or any method or process so disclosed, may be combined in any combination, except combinations where some of such features are mutually exclusive. 
     The terms “include,” “have,” and variations thereof, as used herein, have the same meaning as the term “comprise” or appropriate variation thereof. Furthermore, the term “based on”, as used herein, means “based at least in part on.” Thus, a feature that is described as based on some stimulus can be based on the stimulus or a combination of stimuli including the stimulus. In addition, the terms “first” and “second” are used to identify individual elements and may not meant to designate an order or number of those elements. 
     The present description has been shown and described with reference to the foregoing examples. It is understood, however, that other forms, details, and examples can be made without departing from the spirit and scope of the present subject matter that is defined in the following claims.