PATENT DOCUMENT

Publication Number: US-11791974-B2
Application Number: US-202217899556-A
Country: US
Kind Code: B2

Title: Electrical balanced duplexer-based duplexer

Abstract:
An electrical balance duplexer (EBD) may be used to isolate a transmitter and receiver that share a common antenna. By using impedance gradients to provide impedances that cause balance-unbalance transformers (balun) of the EBD to cut-off access to the common antenna rather than duplicate the antenna impedance, the EBD is balanced. Such cut-offs may have a lower insertion loss than an EBD that merely duplicates the antenna impedance to separate the differential signals of the receiver/transmitter from the common mode signal.

Claims:
What is claimed is: 
     
       1. An electrical balance duplexer for transmission and reception of signals via an antenna, the electrical balance duplexer comprising:
 a transmitter balun having a first side coupled to a transmitter using one or more transmit signals that are differential signals from the transmitter, the transmitter balun having a second side inductively coupled to the first side; 
 a transmitter impedance gradient coupled to a first set of windings on the second side of the transmitter balun between the transmitter balun and a first ground connection; and 
 a transmitter impedance tuner coupled to a second set of windings on the second side of the transmitter balun between the transmitter balun and a second ground connection, wherein the transmitter impedance tuner and the transmitter impedance gradient are configured to:
 in a transmit mode, cause the one or more transmit signals to traverse the transmitter balun to the antenna connected to the second side and the antenna between the first and second sets of windings, the traversal of the one or more signals based on transmit frequencies of the one or more transmit signals, and 
 in a receive mode, block the one or more transmit signals from traversing the transmitter balun to the antenna from the transmitter by transmitting the one or more transmit signals to the first and second ground connection based on transmit frequencies of the one or more transmit signals. 
 
 
     
     
       2. The electrical balance duplexer of  claim 1 , the first side of the transmitter balun having third and fourth sets of windings coupled in series with the differential signals from the transmitter coupled at opposite ends of the series of the third and fourth sets of windings. 
     
     
       3. The electrical balance duplexer of  claim 2 , the first side of the transmitter balun having a third ground connection between the third and fourth sets of windings. 
     
     
       4. The electrical balance duplexer of  claim 1 , the transmitter impedance gradient being configured to provide a first impedance in the transmit mode and a second impedance in the receive mode for the transmit frequencies. 
     
     
       5. The electrical balance duplexer of  claim 1 , the transmitter impedance tuner being configured to provide a first impedance in the transmit mode and a second impedance in the receive mode for the transmit frequencies. 
     
     
       6. The electrical balance duplexer of  claim 1 , the transmitter impedance gradient being located adjacent to a positive terminal of the first side configured to receive a positive differential signal from the transmitter. 
     
     
       7. The electrical balance duplexer of  claim 6 , the transmitter impedance tuner being located adjacent to a negative terminal of the first side configured to receive a negative differential signal from the transmitter. 
     
     
       8. The electrical balance duplexer of  claim 1 , further comprising a receiver balun having a third side coupled to a receiver using one or more receive signals that are differential receiver signals to the receiver, the receiver balun having a fourth side inductively coupled to the third side. 
     
     
       9. The electrical balance duplexer of  claim 8 , further comprising a receiver impedance gradient coupled to a fifth set of windings on the fourth side of the receiver balun between the receiver balun and a fourth ground connection, and a receiver impedance tuner coupled to a sixth set of windings on the fourth side of the receiver balun between the receiver balun and a fifth ground connection. 
     
     
       10. The electrical balance duplexer of  claim 9 , the receiver impedance tuner and the receiver impedance gradient being configured to, in a receive mode, cause the one or more receive signals to traverse the receiver balun from the antenna connected to the fourth side between the fifth and sixth sets of windings to differential terminals of the receiver coupled to the third side, the traversal of the one or more receive signals based on receive frequencies of the one or more receive signals. 
     
     
       11. The electrical balance duplexer of  claim 10 , the receiver impedance tuner and the receiver impedance gradient being configured to, in a transmit mode, block one or more receive signals from traversing the receiver balun from the antenna to the receiver by transmitting the one or more receive signals to the fourth and fifth ground connections based on the receive frequencies of the one or more receive signals. 
     
     
       12. The electrical balance duplexer of  claim 10 , the receiver balun comprising a sixth ground connection between windings of the third side between differential receiver terminals coupled at opposite ends of the windings of the third side. 
     
     
       13. An electrical balance duplexer for transmission and reception of signals via an antenna, the electrical balance duplexer comprising:
 a transmitter balun having a first side coupled to a transmitter and a second side inductively coupled to the first side; 
 the antenna coupled to the second side; 
 a transmitter impedance gradient coupled to the first side of the transmitter balun between the transmitter balun and a ground connection; and 
 a transmitter impedance tuner coupled to the first side of the transmitter balun between the transmitter balun and the ground connection, wherein the transmitter impedance gradient and the transmitter impedance tuner are configured to:
 in a receive mode, block one or more transmit signals from traversing the transmitter balun to the antenna based on a transmit frequency of the one or more transmit signals by transmitting the one or more transmit signals to the ground connection, and 
 in a transmit mode, pass the one or more transmit signals to the antenna based on the transmit frequency. 
 
 
     
     
       14. The electrical balance duplexer of  claim 13 , further comprising a receiver balun having a third side coupled to a receiver and a fourth side inductively coupled to the third side with the antenna coupled to the fourth side. 
     
     
       15. The electrical balance duplexer of  claim 14 , further comprising a receiver impedance gradient coupled to the third side of the receiver balun between the receiver balun and the ground connection. 
     
     
       16. The electrical balance duplexer of  claim 15 , further comprising a receiver impedance tuner coupled to the third side of the receiver balun between the receiver balun and the ground connection. 
     
     
       17. The electrical balance duplexer of  claim 16 , the receiver impedance gradient and the receiver impedance tuner being configured to, in a transmit mode, block one or more receive signals from traversing the receiver balun from the antenna to the receiver based on a receive frequency of the one or more receive signals by transmitting the one or more receive signals to the ground connection. 
     
     
       18. The electrical balance duplexer of  claim 17 , the receiver impedance gradient and the receiver impedance tuner being configured to, in a receive mode, pass one or more receive signals from the antenna across the receiver balun to the receiver based on the receive frequency. 
     
     
       19. An electrical balance duplexer for transmission and reception of signals via an antenna, the electrical balance duplexer comprising:
 a receiver balun having a first side coupled to a receiver and a second side inductively coupled to the first side, the receiver balun having first sets of windings across the first and second sides; and 
 a receiver impedance gradient coupled to a first end of the first sets of windings and between the receiver balun and a ground connection; and 
 a receiver impedance tuner coupled to a second end of the first sets of windings opposite of the first end and between the receiver balun and the ground connection, the receiver impedance gradient and the receiver impedance tuner being configured to:
 in a receive mode, cause one or more receive signals to traverse the receiver balun to the receiver from the antenna, and 
 in a transmit mode, block the one or more receive signals from traversing the receiver balun to the receiver from the antenna by transmitting the one or more receive signals to the ground connection. 
 
 
     
     
       20. The electrical balance duplexer of  claim 19 , a transmitter balun having a third side coupled to a transmitter and a fourth side inductively coupled to the third side, the transmitter balun having second sets of windings across the third and fourth sides;
 a transmitter impedance gradient coupled to a third end of the second sets of windings and between the transmitter balun and the ground connection; and 
 a transmitter impedance tuner coupled to a fourth end of the second sets of windings opposite of the third end and between the transmitter balun and the ground connection, the transmitter impedance gradient and the transmitter impedance gradient being configured to, in a transmit mode, cause one or more transmit signals to traverse the transmitter balun from the transmitter to the antenna, and, in a receive mode, block the one or more transmit signals from traversing the receiver balun to the antenna from the transmitter by transmitting the one or more transmit signals to the ground connection, the receiver balun being configured to transmit the one or more receive signals to the receiver as differential signals, and the transmitter balun being configured to receive the one or more transmit signals from transmitter as differential signals.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 17/188,574, entitled “ELECTRICAL BALANCED DUPLEXER-BASED DUPLEXER,” filed on Mar. 1, 2021, which is a continuation of U.S. patent application Ser. No. 16/582,769, entitled “ELECTRICAL BALANCED DUPLEXER-BASED DUPLEXER”, filed on Sep. 25, 2019, which issued as U.S. Pat. No. 10,938,542 on Mar. 2, 2021, each of which is incorporated by reference herein in its entirety for all purposes. 
    
    
     BACKGROUND 
     The present disclosure relates generally to wireless communication systems and, more specifically, to systems and methods for electrical balanced duplexer (EBD)-based power amplifier duplexers (PADs). 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Transmitters and receivers may be coupled to an antenna to enable an antenna to both receive and transmit from an electronic device. Certain of these electronic devices may use PADs to isolate the transmitter and receiver ports from each other and control connection of the transmitters/receivers to the antenna. The PADs may include multiple duplexers and switches to provide isolation between the transmitter and receiver ports. Since the applications for the antenna, the transmitters, and the receivers may be diverse, the PADs may include numerous band pass filters that are frequency-dependent. In other words, to increase flexibility additional band pass filters may be added to the PAD. However, additional band pass filters consume additional space and add costs to manufacture of the electrical device. 
     SUMMARY 
     A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
     Certain wireless electronic devices use duplexers to enable transmitters and receivers to share an antenna. In some situations, the electronic device may be used across multiple different frequencies. An electrical balance duplexer (EBD) may be used to accommodate dynamic frequency usage compared to arrays of pass-band filters. The EBD may include balance-unbalance transformer (balun) circuits that include respective baluns that are coupled to impedance gradients that provide a respective impedance at a corresponding frequency to enable/block traversal of the balun. For example, some embodiments, may include a transmitter balun that is configured to receive a first impedance (e.g., a high impedance) at a first frequency from a transmitter impedance gradient to block signals from the antenna from crossing the transmitter balun to the transmitter while enabling signals from the transmitter to traverse the transmitter balun using a second impedance (e.g., a low impedance) at a second frequency from the transmitter impedance gradient. This frequency division is applied by the EBD because the first and second frequencies are different. For instance, the first and second frequency may fall in different (i.e., non-overlapping frequency bands). 
     A receiver balun may function similarly to the transmitter balun. For example, the receiver balun that is configured to receive a first impedance at a first frequency from a receiver impedance gradient to block signals from the transmitter from crossing the receiver balun to the receiver while enabling signals from the antenna to traverse the receiver balun using a second impedance at a second frequency from the receiver impedance gradient. This frequency division is applied by the EBD because the first and second frequencies are different. For instance, the first and second frequency may fall in different (i.e., non-overlapping frequency bands). 
     In some embodiments, the impedance gradients may be assisted using impedance tuners that reduce demands on the impedance gradients. For example, the impedance tuners may provide a low impedance in a pass band while matching an impedance of a corresponding impedance gradient in a block band. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: 
         FIG.  1    is a block diagram of an electronic device that includes a duplexer, in accordance with an embodiments of the present disclosure; 
         FIG.  2    is a perspective view of a notebook computer representing an embodiment of the electronic device of  FIG.  1   ; 
         FIG.  3    is a front view of a hand-held device representing another embodiment of the electronic device of  FIG.  1   ; 
         FIG.  4    is a front view of another hand-held device representing another embodiment of the electronic device of  FIG.  1   ; 
         FIG.  5    is a front view of a desktop computer representing another embodiment of the electronic device of  FIG.  1   ; 
         FIG.  6    is a front view and side view of a wearable electronic device representing another embodiment of the electronic device of  FIG.  1   ; 
         FIG.  7    is a schematic diagram of the duplexer of  FIG.  1    having an electrical balance duplexer (EBD), in accordance with embodiments of the present disclosure; 
         FIG.  8    is a schematic diagram for an alternative embodiment of the EBD of  FIG.  7    having a transmitter impedance gradient and a receiver impedance gradient, in accordance with embodiments of the present disclosure; 
         FIG.  9    is a schematic diagram of the EBD of  FIG.  8    with the transmitter impedance gradient causing a transmitter balun to enable transmission of signals to an antenna and the receiver impedance gradient causing a receiver balun to block transmission of the signals to the receiver, in accordance with embodiments of the present disclosure; 
         FIG.  10    is a schematic diagram of the EBD of  FIG.  8    with the transmitter impedance gradient causing a transmitter balun to block transmission of signals having a transmission frequency from the transmitter to an antenna and the receiver impedance gradient causing a receiver balun to enable transmission of signals having a receive frequency to the receiver, in accordance with embodiments of the present disclosure; 
         FIG.  11    is a schematic diagram of the EBD of  FIG.  8    with impedance tuners for each impedance gradient, in accordance with embodiments of the present disclosure; 
         FIG.  12    is a schematic diagram of the EBD of  FIG.  11    with differential signals to be transmitted from the transmitter and differential signals to be received by the receiver, in accordance with embodiments of the present disclosure; 
         FIG.  13    is an alternative embodiment of the EBD of  FIG.  8    with the impedance gradients and impedance tuners on a same side of a corresponding balun with the transmitter/receiver, in accordance with embodiments of the present disclosure; and 
         FIG.  14    is a block diagram of process used by the EBD of  FIGS.  8 - 13   , in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     Electronic devices may utilize one or more duplexers. Duplexers are devices that enable bidirectional communication over a single path while separating components that utilize the single path. For example, duplexers may separate a receiver for the electronic device from a transmitter for the electronic device that both share an antenna of the electronic device. Conventional duplexers may include filters of any kind to achieve this separation. For example, duplexers may include surface-acoustic wave (SAW) filters and/or bulk-acoustic waves (BAW) filters based on microacoustic principles or may include an inductor-capacitor-resistor (LCR) filter based on resonating circuits of inductors and capacitors to separate the transmitter and the receiver. 
     In addition to or alternative to SAW/BAW filters, a CMOS N-Path filter, a spatio-temporal circulator, or an electrical balanced duplexer (EBD) may be used in the duplexers. The EBD is a duplexer, which uses a balance-unbalance transformer (balun) in order to separate the differential signal from the common mode signal. 
     A substantial disadvantage of using the N-Path filter, spatio-temporal circulator, or the EBD exists in that these technologies have a higher insertion loss compared to using SAW/BAW filters. A further drawback regarding the EBD is that the traditional EBD uses an active replica of an antenna impedance in order to reach a highest isolation. Any antenna impedance shift may disturb the duplex function and degrade the isolation between the transmit path and the receive path. As discussed below in more detail, the EBD discussed herein differs from traditional EBDs in that a balun of the disclosed EBD in a balanced state is used to cut off the path to the antenna and not just to separate the differential signals of the receiver/transmitter from the common mode signal. 
     With the foregoing in mind, there are many suitable electronic devices that may benefit from the embodiments of duplexers described herein. Turning first to  FIG.  1   , an electronic device  10  according to an embodiment of the present disclosure may include, among other things, one or more processor(s)  12 , memory  14 , nonvolatile storage  16 , a display  18 , antenna(s)  20 , input structures  22 , an input/output (I/O) interface  24 , a network interface  25 , and a power source  29 . The various functional blocks shown in  FIG.  1    may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium), or a combination of both hardware and software elements. It should be noted that  FIG.  1    is merely one example of a particular implementation and is intended to illustrate the types of components that may be present in electronic device  10 . 
     By way of example, the electronic device  10  may represent a block diagram of the notebook computer depicted in  FIG.  2   , the handheld device depicted in  FIG.  3   , the handheld device depicted in  FIG.  4   , the desktop computer depicted in  FIG.  5   , the wearable electronic device depicted in  FIG.  6   , or similar devices. It should be noted that the processor(s)  12  and other related items in  FIG.  1    may be generally referred to herein as “data processing circuitry.” Such data processing circuitry may be embodied wholly or in part as software, firmware, hardware, or any combination thereof. Furthermore, the data processing circuitry may be a single contained processing module or may be incorporated wholly or partially within any of the other elements within the electronic device  10 . 
     In the electronic device  10  of  FIG.  1   , the processor(s)  12  may be operably coupled with the memory  14  and the nonvolatile storage  16  to perform various algorithms. Such programs or instructions executed by the processor(s)  12  may be stored in any suitable article of manufacture that includes one or more tangible, computer-readable media at least collectively storing the instructions or routines, such as the memory  14  and the nonvolatile storage  16 . The memory  14  and the nonvolatile storage  16  may include any suitable articles of manufacture for storing data and executable instructions, such as random-access memory, read-only memory, rewritable flash memory, hard drives, and optical discs. In addition, programs (e.g., an operating system) encoded on such a computer program product may also include instructions that may be executed by the processor(s)  12  to enable the electronic device  10  to provide various functionalities. 
     In certain embodiments, the display  18  may be a liquid crystal display (LCD), which may allow users to view images generated on the electronic device  10 . In some embodiments, the display  18  may include a touch screen, which may allow users to interact with a user interface of the electronic device  10 . Furthermore, it should be appreciated that, in some embodiments, the display  18  may include one or more organic light emitting diode (OLED) displays, or some combination of LCD panels and OLED panels. 
     The input structures  22  of the electronic device  10  may enable a user to interact with the electronic device  10  (e.g., pressing a button to increase or decrease a volume level). The I/O interface  24  may enable electronic device  10  to interface with various other electronic devices, as may the network interface  25 . The network interface  25  may include, for example, one or more interfaces for a personal area network (PAN), such as a Bluetooth network, for a local area network (LAN) or wireless local area network (WLAN), such as an 802.11x Wi-Fi network, and/or for a wide area network (WAN), such as a 3rd generation (3G) cellular network, universal mobile telecommunication system (UMTS), 4th generation (4G) cellular network, long term evolution (LTE) cellular network, or long term evolution license assisted access (LTE-LAA) cellular network, 5th generation (5G) cellular network, and/or 5G New Radio (5G NR) cellular network. The network interface  25  may also include one or more interfaces for, for example, broadband fixed wireless access networks (WiMAX), mobile broadband Wireless networks (mobile WiMAX), asynchronous digital subscriber lines (e.g., ADSL, VDSL), digital video broadcasting-terrestrial (DVB-T) and its extension DVB Handheld (DVB-H), ultra-Wideband (UWB), alternating current (AC) power lines, and so forth. For example, network interfaces  25  may be capable of joining multiple networks, and may employ one or more antennas  20  to that end. Additionally or alternatively, the network interfaces  25  may include at least one duplexer  26  that enables multiple components (e.g., the receiver  27  and the transmitter  28 ) with separate paths (e.g., transmit path and receive path) to use one of the antennas  20  while providing separation between the multiple components. As further illustrated, the electronic device  10  may include a power source  29 . The power source  29  may include any suitable source of power, such as a rechargeable lithium polymer (Li-poly) battery and/or an alternating current (AC) power converter. 
     In certain embodiments, the electronic device  10  may take the form of a computer, a portable electronic device, a wearable electronic device, or other type of electronic device. Such computers may include computers that are generally portable (such as laptop, notebook, and tablet computers) as well as computers that are generally used in one place (such as conventional desktop computers, workstations, and/or servers). In certain embodiments, the electronic device  10  in the form of a computer may be a model of a MACBOOK®, MACBOOK® PRO, MACBOOK AIR®, IMAC®, MAC® MINI, OR MAC PRO® available from Apple Inc. By way of example, the electronic device  10 , taking the form of a notebook computer  10 A, is illustrated in  FIG.  2    in accordance with one embodiment of the present disclosure. The depicted computer  10 A may include a housing or enclosure  36 , a display  18 , input structures  22 , and ports of an I/O interface  24 . In one embodiment, the input structures  22  (such as a keyboard and/or touchpad) may be used to interact with the computer  10 A, such as to start, control, or operate a GUI or applications running on computer  10 A. For example, a keyboard and/or touchpad may allow a user to navigate a user interface or application interface displayed on display  18 . 
       FIG.  3    depicts a front view of a handheld device  10 B, which represents one embodiment of the electronic device  10 . The handheld device  10 B may represent, for example, a portable phone, a media player, a personal data organizer, a handheld game platform, or any combination of such devices. By way of example, the handheld device  10 B may be a model of an IPOD® OR IPHONE® available from Apple Inc. of Cupertino, Calif. The handheld device  10 B may include an enclosure  36  to protect interior components from physical damage and to shield them from electromagnetic interference. The enclosure  36  may surround the display  18 . The I/O interfaces  24  may open through the enclosure  36  and may include, for example, an I/O port for a hardwired connection for charging and/or content manipulation using a standard connector and protocol, such as the Lightning connector provided by Apple Inc., a universal serial bus (USB), or other similar connector and protocol. 
     User input structures  22 , in combination with the display  18 , may allow a user to control the handheld device  10 B. For example, the input structures  22  may activate or deactivate the handheld device  10 B, navigate user interface to a home screen, a user-configurable application screen, and/or activate a voice-recognition feature of the handheld device  10 B. Other input structures  22  may provide volume control, or may toggle between vibrate and ring modes. The input structures  22  may also include a microphone may obtain a user&#39;s voice for various voice-related features, and a speaker may enable audio playback and/or certain phone capabilities. The input structures  22  may also include a headphone input may provide a connection to external speakers and/or headphones. 
       FIG.  4    depicts a front view of another handheld device  10 C, which represents another embodiment of the electronic device  10 . The handheld device  10 C may represent, for example, a tablet computer, or one of various portable computing devices. By way of example, the handheld device  10 C may be a tablet-sized embodiment of the electronic device  10 , which may be, for example, a model of an IPAD® available from Apple Inc. of Cupertino, Calif. 
     Turning to  FIG.  5   , a computer  10 D may represent another embodiment of the electronic device  10  of  FIG.  1   . The computer  10 D may be any computer, such as a desktop computer, a server, or a notebook computer, but may also be a standalone media player or video gaming machine. By way of example, the computer  10 D may be an IMAC®, a MACBOOK®, or other similar device by Apple Inc. It should be noted that the computer  10 D may also represent a personal computer (PC) by another manufacturer. A similar enclosure  36  may be provided to protect and enclose internal components of the computer  10 D such as the display  18 . In certain embodiments, a user of the computer  10 D may interact with the computer  10 D using various input structures  22 , such as the keyboard  22 A or mouse  22 B, which may connect to the computer  10 D. 
     Similarly,  FIG.  6    depicts a wearable electronic device  10 E representing another embodiment of the electronic device  10  of  FIG.  1    that may be configured to operate using the techniques described herein. By way of example, the wearable electronic device  10 E, which may include a wristband  38 , may be an APPLE WATCH® by Apple Inc. However, in other embodiments, the wearable electronic device  10 E may include any wearable electronic device such as, for example, a wearable exercise monitoring device (e.g., pedometer, accelerometer, heart rate monitor), or other device by another manufacturer. The display  18  of the wearable electronic device  10 E may include a touch screen display  18  (e.g., LCD, OLED display, active-matrix organic light emitting diode (AMOLED) display, and so forth), as well as input structures  22 , which may allow users to interact with a user interface of the wearable electronic device  10 E. 
     With the foregoing in mind,  FIG.  7    illustrates an embodiment of the duplexer  26  that includes an EBD  41 . As illustrated, the EBD  41  provides isolation between the receiver  27  and the transmitter  28  while enabling both the receiver  27  and the transmitter  28  to utilize the antenna  20 . As illustrated, the duplexer  26  may include a low-noise amplifier (LNA)  42  that may be used to amplify received signals for the receiver  27 . In some embodiments, an iteration of the LNA  42  may be located within the receiver  27  in addition to or alternative the LNA  42  within the duplexer  26 . In some embodiments, an iteration of the LNA  42  may be located within the receiver  27  in addition to or alternative the LNA  42  within the duplexer  26 . The duplexer  26  may also include a power amplifier (PA)  43  that receives signals from the transmitter  28 . The PA  43  amplifies the signals to a suitable level to drive the transmission of the signals via the antenna  20 . In some embodiments, an iteration of the PA  43  may be located within the transmitter  28  in addition to or alternative the PA  43  within the duplexer  26 . These signals are to be transmitted via the antenna  20 . 
     The EBD  41  includes a secondary winding  45  that may be used to selectively pass a signal from the antenna to the LNA  42  (and to the receiver  27 ) via primary windings  46  and/or  47 . Signals from the PA  43  (and from the transmitter  28 ) are passed to antenna  20  via a line  48  coupled between the primary windings  46  and  47 . A balancing network  49  of the EBD  41  may be used to actively replicate an impedance of the antenna  20  to maximize isolation between the receiver  27  and the transmitter  28 . However, if the impedance of the antenna  20  shifts, a duplexer function of the duplexer  26  is disturbed and the isolation between the receiver  27  and the transmitter  28  are degraded. Instead, the duplexer  26  may use an alternative arrangement of the EBD  41 , such as embodiments of the duplexer  26  illustrated in  FIGS.  8 - 13   , that reduce the insertion loss resulting from using the EBD  41  in  FIG.  7    while eliminating the antenna replica dependency of  FIG.  7    to improve flexibility of frequencies used in the duplexer  26 . 
       FIG.  8    is a simplified block diagram of an embodiment of the duplexer  26  with an EBD  41  that does not include the antenna replica dependency present in  FIG.  7   . As illustrated, the duplexer  26  is coupled to the antenna  20  and provides selective access to and from the antenna  20  by the receiver  27  and the transmitter  28  of the electronic device  10 . The duplexer  26  includes transmitter balun circuitry  58  having a transmitter balun  59  and receiver balun circuitry  60  having a receiver balun  61 . The transmitter  28  is coupled to a first side of the transmitter balun  59  while the receiver  27  is coupled to a corresponding first side of the receiver balun  61 . 
     The transmitter balun circuitry  58  and the receiver balun circuitry  60  each enables a corresponding path (e.g., between the antenna  20  and the receiver  27 /the transmitter  28 ) to be blocked or allowed. This selective blocking/passing may be set for the transmitter balun circuitry  58  using an impedance gradient  62  coupled to a second side of the transmitter balun  59  opposite the connection to the transmitter  28 , and the state may be set for the receiver balun circuitry  60  using an impedance gradient  64  coupled to a second side of the receiver balun  61  opposite the connection to the receiver  27 . The impedance gradients  62  and  64  may be implemented using discrete lumped components or distributed components that set desired impedances for certain frequencies and may couple certain frequencies to ground  65  with a low impedance. Regardless of implementation type, the impedance gradients  62  and  64  act as filters having a relative high impedance in a “pass” band compared to a relative low impedance (e.g., short to ground  65 ) in a “block” band. 
     Furthermore, the transmitter balun  59  includes a winding  66  that may produce an electromagnetic field due to excitation due to the connection of the winding  66  to the transmitter  28  and a common return  68  (e.g., ground). The field generated at the winding  66  may cause resulting signals in windings  70  and/or  72  depending on the frequency range of the signals and the impedance provided by the impedance gradient  62  in that frequency range. The impedance gradient  62  is coupled to the winding  70  and a connection of the winding  72  to a common return  74 . A line  76  is coupled between the windings  70  and  72  to enable the signals from the transmitter  28  to the antenna  20  via an antenna balun  77  when the transmitter balun  59  is set to pass transmission signals using the impedance gradients  62  and/or  64 . 
     The receiver balun  61  includes a winding  78  that may generate a signal based on an electromagnetic field generated by windings  80  and/or  82  based on the impedance gradient  64  providing an impedance to the receiver balun  61  that enables passing of signals across the receiver balun  61 . A line  84  between the windings  80  and  82  couples the pair of windings  80  and  84  to the antenna balun  77 . Specifically, the lines  76  and  84  are coupled to opposite ends of a winding  86  of the antenna balun  77 . The impedance gradients  62  and  64  cause a transmission signal to be passed to the line  76 , when the duplexer  26  permits transmission of signals having a transmission frequency. The passing of the transmission signal causes the winding  86  to generate an electromagnetic field that induces a signal on a secondary winding  88  of the antenna balun  77  that is passed to the antenna  20  to be broadcast. 
     The impedance gradients  62  and  64  cause a received signal to be passed from the antenna to the receiver  27 , when the duplexer  26  permits signals having a receive frequency using an impedance from the impedance gradient  64 . Although the illustrated embodiment includes a single antenna balun  77  to provide connection to the antenna  20 , any other suitable implementation used to transmit signals between the antenna  20  and a corresponding lines  76  and  84 . 
       FIG.  9    is a schematic diagram illustrating the duplexer  26  in a transmission mode for at least one transmission frequency. As previously noted, the impedance gradient  62  acts a filter that provides a high impedance for a pass band. For example, the impedance gradient  62  may select an “open” position  100  instead of a “short” position  102 . The “open” position  100  connects the winding  70  to a relatively high impedance compared to a relatively low impedance provided when the short position  102  is selected to provide a low impedance path to ground  65 . As illustrated, the impedance gradient  62  may be in a transmission mode for the transmission frequency. With the impedance gradient  62  configured to provide a high impedance path for the winding  80  at the transmission frequency, transmission signals from the transmitter  28  are passed in a transmission path  104  across the transmitter balun  59  and ultimately to the antenna  20 . 
     The impedance gradient  64  functions similar to the impedance gradient  62  except that the impedance gradient  64  is to block transmission frequencies from being transmitted to the receiver  27  when in the transmission frequency. To achieve this isolation, the impedance gradient  64  is set to select between coupling the winding  80  to a “open” position  106  and a “short” position  108 , each respectively similar to the “open” position  100  and the “short” position  102 . Since the duplexer  26  is to block the transmission frequency from the receiver  27 , the impedance gradient  64  provides a low impedance connection to the winding  80  for the transmission frequency. With the impedance gradient  62  configured to provide a low impedance path for the winding  80  at the transmission frequency, transmission signals from the antenna  20  are passed in a transmission path  110  until being stopped from transference across the receiver balun  61  due to the low impedance connection provided by the impedance gradient  64  to the winding  80 . 
     Since the EBD  41  has two impedance gradients  62  and  64  that may be controlled individually and block corresponding frequencies, the EBD  41  may be used to implement the duplexer  26  as a frequency division duplexer.  FIG.  10    is a schematic diagram illustrating the duplexer  26  for at least one receive frequency. The receiver mode of the duplexer  26  for the receive frequency includes the impedance gradient  62  coupling the winding  70  to a low impedance path causing a transmission path  112  to be blocked preventing transference of transmission signals across the transmitter balun  59 . Furthermore, the receiver mode of the duplexer  26  for the receive frequency includes the impedance gradient  64  coupling the winding  80  to a high impedance path causing received signals to be passed along a receive path  114  from the antenna  20  to the receiver  27  via receiver balun  61 . 
     With the impedance gradient  62  configured to provide a high impedance path for the winding  80  at the transmission frequency, transmission signals from the transmitter  28  are passed in a transmission path  104  across windings  66  and  72  to the line  76  and ultimately to the antenna  20 . 
     Since the impedance gradients  62  and  64  may be implemented using real-word components, the high impedance and low impedance settings for impedance gradients  62  and  64  may be values other than ideal short and open values (e.g., 0Ω and ∞Ω). To address the non-ideal operation of the impedance gradients  62  and  64 , an additional component, an impedance tuner, may be used to compensate for such non-ideal values of impedances. Furthermore, a concern in operation of the EBD  41  can be an abrupt change in impedance at the transmission and receive frequencies. By using the impedance tuner, the demands on the impedance gradients  62  and  64  may also be reduced.  FIG.  11    illustrates an embodiment of the duplexer  26  with impedance tuners  120  and  122 . Whereas the impedance gradients  62  and  64  act as filters, the impedance tuners  120  have a low impedance in the “pass” band for the respective balun and replicates the impedance of the corresponding impedance gradient in the “block” band. In other words, in some embodiments, the impedance tuners  120  and  122  may always provide a low impedance lower than the high impedance of a corresponding impedance gradient for passed frequencies while providing a similar low impedance that is provided by the corresponding impedance gradient for blocked frequencies. 
     The illustrated embodiment of the EBD  41  in  FIG.  11    also includes windings  124  and  126  that respectively supplement the windings  66  and  78 . However, in some embodiments, the windings  66  and  124  may be combined into a single winding, and the windings  78  and  126  may be combined into a single winding. 
     Since signals to the receiver  27  and from the transmitter  28  may be differential signals, some embodiments of the EBD  41  may address differential transmittance of such signals. For instance, in  FIG.  12   , the EBD  41  includes a positive transmitter terminal  130  and a negative transmitter terminal  132  that together form a differential signal from the transmitter  28  (e.g., via the PA  43 ). Thus, in the EBD  41  of  FIG.  12   , the transmitter balun  59  may be used to convert the differential signal from the transmitter  28  to a single signal on the line  76 . Similarly, the EBD  41  of  FIG.  12    includes a positive receiver terminal  134  and a negative receiver terminal  136  that together form a differential signal to the receiver  27  (e.g., via the LNA  42 ). Thus, in the EBD  41  of  FIG.  12   , the receiver balun  61  may be used to convert the single signal on the line  84  to a differential signal suitable for the receiver  27 . 
     The impedance gradients  62  and  64  and the impedance tuners  120  and  122  have been illustrated on as coupled to the corresponding baluns at a side opposite side (e.g., secondary winding-side of the transmitter balun  59 ) than the receiver  27  or the transmitter  28  in the foregoing embodiments. However, the impedance gradients  62  and  64  and the impedance tuners  120  and  122  may be coupled to the same respective side (e.g., the primary winding-side of the transmitter balun  59 ) as the receiver  27  or the transmitter  28 .  FIG.  13    illustrates a schematic diagram of an embodiment of the duplexer  26  having such an arrangement. As illustrated, the transmitter  28  is coupled to the transmitter balun  59  between the windings  66  and  124 , and the receiver  27  is coupled to the receiver balun  61  between the windings  78  and  126 . Moreover, the impedance gradient  62  is coupled between the winding  66  and ground  65  instead of between the winding  70  and ground  65  illustrated in previous embodiments. Furthermore, the impedance tuner  120  is coupled between the winding  124  and ground  65  instead of between the winding  72  and ground  65  illustrated in previous embodiments. Moreover, the impedance gradient  64  is coupled between the winding  78  and ground  65  instead of between the winding  82  and ground  65  illustrated in previous embodiments. Furthermore, the impedance tuner  122  is coupled between the winding  126  and ground  65  instead of between the winding  80  and ground  65  illustrated in previous embodiments. In some embodiments, the impedance tuners  120  and  122  may be omitted from the duplexer  26  of  FIG.  13   . 
       FIG.  14    is flow diagram of a process  200  that may be used by the embodiments of the EBD  41  discussed in relation to  FIGS.  8 - 13   . The process  200  includes the impedance gradient  62  providing a first low impedance to the transmitter balun  59  for a receive frequency band (block  202 ). The transmitter balun  59  uses the first low impedance to block transmission signals in the receive frequency band from traversing the transmitter balun  59  from the transmitter  28  to the antenna  20  (block  204 ). The impedance gradient  64  provides a second low impedance to the receiver balun  61  for a transmission frequency band (block  206 ). The first low impedance and the second low impedance may be the same impedance level or may be different impedance levels. The receiver balun  61  then uses the second low impedance to block signals in the transmission frequency band from traversing the receiver balun  61  to the receiver  27  (block  208 ). 
     The impedance gradient  62  also provides a first high impedance to the transmitter balun  59  for the transmission frequency band (block  210 ). The transmitter balun  59  uses the first high impedance to enable signals in the transmission frequency band to traverse the transmitter balun  59  from the transmitter  28  to the antenna  20  (block  212 ). The impedance gradient  64  provides a second high impedance to the receiver balun No errors found. 61  for the receive frequency band (block  214 ). The receiver balun  61  uses the second high impedance to enable signals in the receive frequency band to traverse the receiver balun  61  from the antenna  20  to the receiver  27  (block  216 ). 
     In addition, the impedance tuner  120  provides a third low impedance to the transmitter balun  59  for the transmission frequency band to enhance traversal of the transmitter balun  59  by the signals in the transmission frequency band. The third low impedance may be equal the first low impedance and/or the second low impedance. Alternatively, the third low impedance may be different than the first low impedance and the second low impedance. The impedance tuner  120  also provides the first low impedance to the transmitter balun  59  for the receive frequency band to aid the transmitter balun in blocking the signals in the receive frequency band. 
     The impedance tuner  122  provides a fourth low impedance to the receiver balun  61  for the receive frequency band to enhance traversal of the receiver balun  61  by the signals in the receive frequency band. The fourth low impedance may be equal the first low impedance, the second low impedance, and/or the third low impedance. Alternatively, the fourth low impedance may be different than the first low impedance, the second low impedance, and the third low impedance. The impedance tuner  122  also provides the second low impedance to the receiver balun  61  for the transmission frequency band to aid the receiver balun  61  in blocking the signals in the transmission frequency band. 
     The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. For example, the methods may be applied for embodiments having different numbers and/or locations for antennas, different groupings, and/or different networks. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure. 
     The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Metadata:
Filing Date: 20220830
Publication Date: 20231017
Grant Date: 20231017
Priority Date: 20190925
Inventors: MUHAREMOVIC, NEDIM
HUR, JOONHOI
VAZNY, RASTISLAV
Assignee: APPLE INC
CPC Classifications: [{"code": "H04L5/1461", "inventive": true, "first": true, "tree": "[]"}, {"code": "H03H7/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03H11/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03H11/344", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/525", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L5/1461", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/0458", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03H7/463", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03H7/09", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03H7/42", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B1/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03H7/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03H11/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03H11/344", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/16", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 74683165