Abstract: An integrated front-end module (FEM) includes at least one power amplifier (PA) coupled to an antenna without inclusion of a switching element in a transmit signal path in the FEM between an output of the PA and the antenna. The FEM further includes at least one low-noise amplifier (LNA) and a switching circuit coupled in a receive signal path of the FEM between the antenna and an input of the LNA. The switching circuit is configured in a first mode to disable the PA and to connect the input of the LNA to the antenna for receiving signals from the antenna. The switching circuit is configured in a second mode to disconnect the input of the LNA from the antenna and to enable the PA for transmitting signals to the antenna.

Abstract: A band selection switch apparatus includes: a first switch including a first series switch disposed between a transmission input terminal and a first transmission and reception terminal; a second switch including a second series switch disposed between the transmission input terminal and a first transmission terminal; and a third switch including a third series switch disposed between a first reception output terminal and the first transmission and reception terminal. The first series switch includes a first series switch circuit including first series switch elements connected between the transmission input terminal and a first intermediate node, a second series switch circuit including second series switch elements connected between the first intermediate node and the first transmission and reception terminal, and a first shunt switch circuit including first shunt switch elements connected between the first intermediate node and a ground.

Abstract: The radio frequency switching system comprises an input/output terminal connectable to a radio frequency antenna, a receiving terminal, a transmission terminal, a group of diodes operatively interposed between the input/output terminal, the receiving terminal and the transmission terminal, at least a selection device between a receiving configuration, in which the input/output terminal is operatively connected to the receiving terminal, and a transmission configuration, wherein the input/output terminal is operatively connected to the transmission terminal, and a DC/DC voltage converter operatively connected to the group of diodes and able to generate a predetermined output voltage.

Abstract: A high-frequency module includes a wiring board, a first duplexer that separates a transmission signal and a reception signal in a first frequency band, and a second duplexer that separates a transmission signal and a reception signal in a second frequency band whose reception-side frequency band partially overlaps with a frequency band of a third-order harmonic of the first transmission signal. The first duplexer is disposed near a predetermined side on a first main surface of the wiring board, and the second duplexer is disposed near an opposite side opposing the predetermined side. An extended line extending from a first transmission terminal of the first duplexer and an extended line extending from a second reception terminal of the second duplexer are spaced away from each other.

Abstract: A plug-and-play antenna may be used with many different types of wireless communication devices. An antenna may be coupled to an impedance tuning component and a waveform generator. A calibration control module receives radio status information, controls the waveform generator to vary a response of the antenna, and tunes the impedance tuning component to match impedances between a radio and the antenna.

Abstract: Antenna systems that make use of an integrated proximity sensor or other sensor in order to implement a closed loop antenna selection system. In one embodiment, the antenna system is implemented within an exemplary portable wireless device and includes as its primary components for implementing the closed loop antenna selection system: a proximity sensor/microcontroller unit (MCU); a switching apparatus; a baseband front end module (FEM); and a number of antenna modules. The integrated proximity sensor/MCU detects the presence (influence) of a user's hand, or other loading by any other dielectric or metal component, through measurements that take place through the antenna modules and selects the appropriate RF path for transmission and/or reception by the mobile device. Methods of using and testing the aforementioned antenna systems are also disclosed.

Abstract: A signal transmitting-receiving apparatus includes a first switching section, a second switching section, a controller, and an isolation unit. The first switching section is configured to connect Bluetooth signal receiving lines to a Bluetooth antenna. The second switching section configured to connect antennas to one of a Bluetooth receiving terminal, a Wi-Fi signal receiving terminal, and a Wi-Fi signal transmitting terminal. The controller is configured to signal process the Bluetooth signal and a Wi-Fi signal that are transmitted and received. The isolation unit is configured to suppress a signal coupling between the transmitted Bluetooth signal and the Bluetooth signal receiving lines.

Abstract: A distortion compensation system includes a first communication node including a first reception unit including an equalizer configured by a first digital filter unit and a first transmission unit including an emphasis circuit configured by a second digital filter unit, and a second communication node including a second transmission unit transmitting a training pattern before receiving normal data from the first communication node. The equalizer converges a filter constant of the first digital filter unit so that an error of the received training pattern is converged. The first transmission unit performs a distortion compensation using the converged filter constant of the first digital filter unit as at least a part of a filter constant of the second digital filter unit of the emphasis circuit, and then transmits the data.

Abstract: Aspects of this disclosure relate to a mode linearization switch circuit that can adjust an effective impedance provided to an output of an amplifier. In an embodiment, an apparatus includes an amplifier configured to amplify a radio frequency (RF) signal and a mode linearization switch circuit electrically coupled to an output of the amplifier. The mode linearization switch circuit can include a capacitor, a switch in series with the capacitor, and a series LC circuit in parallel with the switch.

Abstract: Disclosed are devices and methods related to a CMOS switch for radio-frequency (RF) applications. In some embodiments, the switch can be configured to include a resistive body-floating circuit to provide improved power handling capability. The switch can further include an electrostatic discharge (ESD) protection circuit disposed relative to the switch to provide ESD protection for the switch. Such a switch can be implemented for different switching applications in wireless devices such as cell phones, including band-selection switching and transmit/receive switching.

Abstract: A method and apparatus is disclosed to couple a transmission amplifier and a reception amplifier to a shared medium. An output of the transmission amplifier is directly coupled to an input of the reception amplifier to form a common connection. The transmission amplifier and the reception amplifier may receive a first amplifier bias via the common connection. In response to the first amplifier bias, the transmission amplifier provides a first communication signal to the shared medium and the reception amplifier does not provide a second communication signal from the shared medium. Alternatively, the transmission amplifier and the reception may receive a second amplifier bias via the common connection. In response to the second amplifier bias, the reception amplifier provides the second communication signal from the shared medium and the transmission amplifier does not provide the first communication signal to the shared medium.

Abstract: Provided is a technique capable of improving isolation characteristics between a plurality of signal paths through which RF signals pass, without using ground electrodes or the like. Wiring electrodes 10a and 20a through which RF signals do not pass simultaneously are formed so as to be adjacent to each other in a central region of a component mounting surface 2a of a circuit board 2, and wiring electrodes 11a and 21a through which RF signals pass simultaneously are formed so as to be distanced from transmission paths 10 and 20. Accordingly, the RF signals do not simultaneously pass through the transmission paths 10 and 20, which are disposed near each other, and thus there is no risk that the RF signal passing through one of the signal paths will interfere with the RF signal passing through the other signal path.

Abstract: A switch is provided, the switch including one or more banks of transistors fabricated on a substrate, wherein body terminals of the transistors in each bank are configured to be individually controlled to have respective body voltages. The values of the body voltages are determined to provide optimum linearity of power transfer by changing properties of the substrate with respect to the properties of the substrate when the body voltages are commonly biased at a value.

Abstract: A method of electrically coupling a first node and a second node of a switch cell includes biasing the second node and a bias node of the switch cell at a direct current (DC) voltage level of a second voltage level greater than a first voltage level. A first switch unit coupled between the first node and the second node is tuned on by a first control signal having a third voltage level. The third voltage level being greater than the first voltage level, and a difference between the third voltage level and the first voltage level is about twice a difference between the second voltage level and the first voltage level. Also, a second switch unit coupled between the second node and the bias node is turned off by a second control signal having the first voltage level.

Abstract: Apparatus and methods for radio frequency (RF) switches are provided herein. In certain implementations, an RF switching circuit includes an adaptive switch bias circuit that controls gate and/or channel voltages of one or more field effect transistor (FET) switches. Additionally, the adaptive switch bias circuit is powered by a power high supply voltage and a power low supply voltage, and can be used to selectively turn on or off the FET switches based on a state of one or more switch enable signals. The adaptive switch bias circuit adaptively biases that gate and/or channel voltages of the FET switches based on a voltage difference between the power high and power low supply voltages to provide switch biasing suitable for use with two or more different power supply voltage levels.

Abstract: Techniques for supporting data transmission and reception on multiple bands for carrier aggregation are disclosed. In an exemplary design, an apparatus (e.g., a wireless device) includes first and second antenna interface circuits coupled to first and second antennas, respectively. The first antenna interface circuit includes a first transmit (TX) filter for a first band, which may be part of a first triplexer or duplexer. The first TX filter filters a first radio frequency (RF) signal prior to transmission via the first antenna. The second antenna interface circuit includes a second TX filter for a second band, which may be part of a second triplexer or duplexer. The second TX filter filters a second RF signal prior to transmission via the second antenna. The first and second RF signals may be transmitted simultaneously on the first and second bands for carrier aggregation.

Abstract: In embodiments of variable antenna match linearity, a wireless device includes a first transceiver and a second transceiver, an antenna via which signals are received, and a linearity controller that varies a linearity of an antenna match circuit associated with the antenna. The linearity controller can determine whether a frequency of an intermodulated signal that includes transmissions from the first and second transceivers is within one of a respective receive band of the first transceiver or the second transceiver. The linearity controller can increase a linearity of the antenna match circuit to mitigate an amplitude of the intermodulated signal in the receive band.

Abstract: The present invention provides a digital television signal reception system, comprising a chip having a low-noise amplifier and a master receiver, at least one slave receiver, and at least one local-oscillator leakage processing unit. The chip receives at least one digital input signal of television channel. The low-noise amplifier amplifies and sends the input signal of television channel to the master/slave receiver. The input signal of television channel is frequency-mixed by the master/slave receiver so as to output an output signal of second television channel and an output signal of second television channel. The local-oscillator leakage processing unit detects and removes local-oscillator leakage of the master receiver included in the output signal of second television channel, so as to avoid interference of the local leakage of master receiver on sensitivity of receiving the output signal of second television channel of slave receiver by the slave television.

Abstract: Discloses are a transmission line having variable characteristic impedance and a combiner configured to combine a plurality of filter by use of the transmission line. The transmission line in accordance with an embodiment of the present invention includes: a first filter junction being connected with a first RF filter and configured to obtain an output signal of the first RF filter; a second filter junction being connected with a second RF filter and configured to obtain an output signal of the second RF filter; a first variable impedance section in which a phase of the output signal of the first RF filter is matched with a preset phase; and a second variable impedance section in which a phase of the output signal of the second RF filter is matched with the preset phase.

Abstract: An electronic device may include radio-frequency transceiver circuitry and antenna structures. The radio-frequency transceiver circuitry may transmit signals for the antenna structures that pass through electrical components such as switches. Harmonics of the transmitted signals may be generated as the signals pass through the electrical components. To reduce interference that might otherwise adversely affect sensitive receiver circuitry in the electronic device, adjustable filter circuitry may be interposed between the electrical components and the antenna structures. Control signals may adjust the adjustable circuitry in real time during operation of an electronic device to ensure that transmitted signals can pass through the adjustable filter circuitry while blocking the harmonic signals.

Abstract: Systems and methods for removing interference from a received signal. A model of a leakage path from a transmit section to a receive section is used to assist in designing a set of iterative filters to remove interference. Modeling the leakage path allows generation of the first approximation of the transfer function of the leakage path traversed by the signals coupled from the transmit section to the receive section. The first approximation narrows down the universe of possible distortions that might occur due to the transfer function of the leakage path. Narrowing down the universe of possible solutions makes the complexity of the interference control section more manageable. An iterative LMS function is used to further refine the coefficients of the adaptive filters.

Abstract: A transmission circuit includes a first path that connects a first terminal for inputting or outputting signals, and one of a pair of second terminals for outputting or inputting the signals; a second path that connects the first terminal and another one of the pair of second terminals; a first circuit including a first capacitor that is serially inserted in the first path, which is configured to perform single-differential conversion on signals transmitted through the first path, to perform impedance matching, and to supply a bias voltage; a second circuit including a first inductor that is serially inserted in the second path, which is configured to perform single-differential conversion on signals transmitted through the second path, to perform impedance matching, and to supply a bias voltage; and a switch that is connected between the two terminals of the pair of second terminals.

Abstract: A transmit/receive switch circuit has a comprises a controllable transmit section and a controllable receive section, having an output and an input coupled to an RF transmit/receive terminal respectively. The transmit section comprises a first transistor having a main current channel coupled between an RF transmit signal input and the RF transmit/receive terminal. The receive section comprises a first transistor having a main current channel coupled between the RF transmit/receive terminal and a RF receive signal output and a second transistor having a main current channel coupled between the RF receive signal output and ground. A signal that is derived from an RF input signal at the RF transmit/receive terminal is rectified. The rectified signal is used to control a control electrode of the second transistor of the receive section to make this transistor increasingly conductive with increasing RF signal amplitude.

Abstract: A multiport radio frequency (RF) switch circuit is disclosed. The switch circuit includes a first transistor that is connected to a first port, a common antenna port, and a first enable line. The first transistor is selectively activatable in response to a first enable signal applied to the first enable line. There is also a second transistor connected to a second port, the common antenna port, and a second enable line. The second transistor is selectively activatable in response to a second enable signal applied to the second enable line. A first inductor connected to the first port and the second port compensates for parasitic capacitance between the first port and the second port from an inactive one of the transistors.

Abstract: A dual pole dual through switch for switching between at least four states. The switch comprises four transistors such as N-channel Metal Oxide Semiconductor transistors, such that at each state at most one transistor is in “on” state, and the others are in “off” state. Each transistor has its own control circuit, which provides zero or negative voltage to the drain of the transistor, positive voltage to the source of the transistor, and control alternating voltage to the gate of the transistor. The switch can be used on-chip for devices. Such devices may include a base station or a handset of a cordless phone.

Abstract: Systems, methods, and apparatus for overvoltage protection in a wireless power receiver are disclosed. One aspect of the disclosure is a wireless power receiver apparatus. The apparatus includes an antenna circuit configured to wirelessly receive power, from a transmitter, at a level sufficient to power or charge a load, wherein the antenna circuit is electrically connected to an overvoltage protection circuit that is electrically connected between the antenna circuit and the load. The apparatus also includes a matching circuit electrically connected to the antenna circuit and a switching element electrically connected to the matching circuit. At least one of the matching circuit or the switching element is configured to control an amount of the received power flowing into the overvoltage protection circuit.

Abstract: The present invention provides surgical apparatus for liposuction in which microwave energy is delivered from a probe into a treatment region to perform a fat liquefying function or a haemostasis function. The apparatus is arranged such that an output microwave field automatically adopts a configuration suitable for the fat liquefying function or haemostasis function depending on the type of tissue encountered by the probe in the treatment region. In particular, by suitable selection of the frequency of the microwave energy, the difference in skin depth of the microwave energy in fat and blood may enable the microwave field to automatically switch its configuration between one suitable for fat liquefying and one suitable for haemostasis without any change required to the amount of microwave power or the energy profile delivered to the probe.

Abstract: A chip includes an RF switch arrangement that has a plurality of RF switches arranged jointly on the chip. Each of the RF switches has at least one first RF connection accessible from outside the chip and one second RF connection accessible from outside the chip. Furthermore, each of the RF switches is designed to activate, in response to a driving, at least one RF path between two of its RF connections. The RF connections of different switches from among the RF switches are separated from one another in terms of radio frequency.

Abstract: In accordance with an embodiment, a filter network is configured to be coupled to a first switch, a second switch, and an output port. The filter network includes a first filter coupled between the first switch and the output port, and the second filter coupled between the second switch and the output port. The first filter has a pass band having a first frequency range that includes a first frequency, and a stop band that includes a second frequency that is a distortion product of the first frequency. The second filter has a second frequency range that includes the second frequency and the stop band that includes the first frequency. The second frequency range is higher in frequency than the first frequency range.

Abstract: Radio-frequency (RF) switch circuits are disclosed providing improved switching performance. An RF switch system includes at least one field-effect transistor (FET) disposed between a first node and a second node, each having a respective source, drain, gate, and body. The system includes a coupling circuit including a first path and a second path, the first path being between the respective source or the respective drain and the respective gate of the at least one FET, the second path being between the respective source or the respective drain and the respective body of the at least one FET. The coupling circuit may be configured to allow discharge of interface charge from either or both of the coupled gate and body.

Abstract: A transceiver includes: a power amplifying circuit arranged to generate differential output signals during a transmitting mode of the transceiver; a balance-unbalance circuit arranged to convert the differential output signals into a single-ended output signal; a switchable matching circuit arranged to receive the single-ended output signal on a signal port of the transceiver during the transmitting mode, and to convert a single-ended receiving signal on the signal port into a single-ended input signal during a receiving mode of the transceiver; and a low-noise amplifying circuit arranged to convert the single-ended input signal into a low-noise input signal during the receiving mode. The power amplifying circuit, the Balun, the switchable matching circuit, and the low-noise amplifying circuit are configured as a single chip.

Abstract: Systems, methods, and other embodiments associated with wireless coexistence through antenna switching are described. According to one embodiment, a method includes selecting one or both of a first transceiver and a second transceiver for connection to an antenna, based, at least in part, on the operating mode of the first transceiver and the second transceiver. The method includes connecting the selected transceiver(s) to the antenna, such that the selected transceiver(s) is enabled to communicate on the antenna and any transceiver(s) not selected is not able to communicate on the antenna.

Abstract: A microwave radio frequency (RF) front end module (FEM) having a low noise amplifier (LNA) with a bypass mode uses a single-pole-triple-throw RF switch that reduces insertion loss to about 1 dB and thereby improves RF receiver sensitivity over existing technology two series connected single-pole-double throw RF switches. The single-pole-triple-throw RF switch may be three metal oxide semiconductor field effect transistor (MOSFET) RF switches that may be arranged with a common source input and isolated independent drain outputs. The RF switches may be single, double or triple gate MOSFET RF switches. The MOSFET RF switches may also be configured as complementary metal oxide semiconductor (CMOS) field effect transistor (FET) RF switches.

Abstract: A concurrent hybrid matching network is disclosed. In an exemplary embodiment, an apparatus includes a phase shifting coupler having a first terminal connected to an antenna, a second terminal connected to a receive signal path, and third terminal connected to a transmit signal path. The apparatus also includes at least one switch to configured to enable one of the receive signal path and the transmit signal path to communicate with the antenna.

Abstract: In a wireless communication device, a reactance element is connected in series between an input/output terminal of a wireless communication and an impedance-matching circuit. A measuring reactance element is provided in an external measuring device, and the types and circuit contacts of respective elements are chosen such that when the reactance element and the measuring reactance element are connected in parallel during power measurement, they together form a band-stop filter circuit that blocks signals of a prescribed frequency band outputted from the wireless communication circuit.

Abstract: Methods and apparatus for voice and data interlacing in a system having a shared antenna. In one embodiment, a voice and data communication system has a shared antenna for transmitting and receiving information in time slots, wherein the antenna can only be used for transmit or receive at a given time. The system determines timing requirements for data transmission and reception and interrupts data transmission for transmission of speech in selected intervals while meeting the data transmission timing and throughput requirements. The speech can be manipulated to fit with the selected intervals, to preserve the intelligibility of the manipulated speech.

Abstract: A transmit and receive RF multiplexer, which includes a first hybrid RF transmit coupler, a first hybrid RF receive coupler, a hybrid RF antenna coupler, and RF bandpass filter and inversion circuitry, is disclosed. The first hybrid RF transmit coupler has a first main transmit port and a pair of transmit ports having a first in-phase transmit port and a first quadrature-phase transmit port. The first hybrid RF receive coupler has a first main receive port and a pair of receive ports having a first in-phase receive port and a first quadrature-phase receive port. The hybrid RF antenna coupler has a main coupler port and a pair of coupler ports having an in-phase coupler port and a quadrature-phase coupler port, such that the main coupler port is coupled to a primary RF antenna.

Abstract: A radio frequency front end module is provided for a high power capability and a high signal band selectivity. The front end module includes an external filter and an integrated circuit coupled with the external filter via two external filter leads. The integrated circuit includes a transmit-receive switch, a power amplifier and a low noise amplifier. The transmit-receive switch alternates between coupling an antenna port to a transmit port and coupling the antenna port to a receive port. The power amplifier amplifies a modulated radio frequency signal. The low noise amplifier amplifies a received radio frequency signal when the antenna port is coupled to the receive port. The external filter can be replaced to adapt to various requirements of signal frequency bands, without the need of modifying the layout of the integrated circuit.

Abstract: A method of operating an electronic device includes providing a plurality of antenna elements, determining that a change is to be made to at least one of the plurality of antenna elements, and scheduling the change to the at least one of the plurality of antenna elements during a time interval that a transmission power amplifier has a power level below a threshold. The change to the at least one of the plurality of antenna elements may also be made responsive to a reduction to the power level of the transmission power amplifier below the threshold.

Abstract: A method for adaptive communication in an HF frequency band includes at least one of the following steps: the determination of a payload subband S that is available for a transmission in the HF band, the selection in the payload subband S of a set of n frequency channels of identical width according to a frequency allocation plan and the quality of the link of each of said channels, or the simultaneous transmission on the n frequency channels of a signal complying with an HF waveform.

Abstract: A power feeding apparatus, power receiving apparatus, wireless power feeding system, and method for wireless transfer of power are provided. The power feeding apparatus includes an impedance detector, a controller, a power transmitter, a variable matching circuit, and a signal transmitter. The controller is configured to provide first control information and second control information based on an impedance detected by the impedance detector. The power feeding apparatus' variable matching circuit is configured to change a variable diameter of a power feeding coil according to the first control information. The power receiving apparatus includes a power receiver, a signal receiver, and a variable matching circuit. The power receiving apparatus'variable matching circuit is configured to change a variable diameter of a power feeding coil according to the second control information provided by the power feeding apparatus.

Abstract: A multi-personal area network (PAN) transceiver includes two or more receiver modules for simultaneously monitoring traffic broadcast on different PANs, but a shared transmitter that switches between the different PANs as needed for transmitting data. The shared transmitter reduces the circuitry that would otherwise be required to transmit on multiple PANs while the multiple receiver modules preserve the ability to monitor traffic on multiple networks.

Abstract: A mobile device includes an antenna, an ESD (Electrostatic Discharge) protection component, a plurality of branches, and a switch. The antenna is configured to transmit and receive an RF (Radio Frequency) signal. The branches provide different inductances or different capacitances, and are respectively coupled to a ground voltage terminal. The switch is coupled through the ESD protection component to the antenna, and switches between the branches according to a control signal such that the antenna is capable of operating in a plurality of frequency intervals. The ESD protection component is configured to protect the switch from being damaged.

Abstract: A wireless electronic device may be used to communicate using multiple wireless standards in adjacent frequency bands. The wireless standards may include Wi-Fi® and cellular standards such as Long Term Evolution (LTE). The wireless electronic device may be provided with wireless communications circuitry that handles Wi-Fi® and cellular signals in adjacent frequency bands such as the Wi-Fi® 2.4 GHz frequency band and LTE bands 38 and 40. The wireless communications circuitry may include a triplexer interposed between transceiver circuitry and an antenna. The triplexer may be used to handle radio-frequency signals in adjacent frequency bands by separating the radio-frequency signals into signals associated with each frequency band. The triplexer may include filters that each pass signals in a respective one of the frequency bands between the transceiver circuitry and the antenna.

Abstract: The transceiver has a transmitter, a receiver, and a three-port network. The transmitter is configured to transmit an outgoing RF signal. The receiver is configured to receive an incoming RF signal. The three-port network includes: a transmission line, configured to have a line length less than a quarter of a wavelength of the incoming RF signal; an antenna port, configured to connect to an antenna; a receiver port, configured to connect the receiver to the antenna port; and a transmitter port, configured to connect the transmitter to the antenna port and the receiver port through the transmission line.

Abstract: A method in which user equipment transmits a signal in a distributed antenna system in which a plurality of antennas is distributed in a cell, comprises the following steps: receiving uplink antenna information from a base station; controlling uplink power on the basis of the uplink antenna information; and transmitting an uplink signal on the basis of the uplink power control, wherein the uplink antenna information indicates a receiving antenna of the base station that receives the uplink signal.

Abstract: A module for an active antenna system for receiving and transmitting radio signals sealed in a housing. It comprises a power connector placed at the outside of the housing for supplying the module with supply power; at least one micro radio for receiving/sending digital radio signals having a digital down-converter/a digital up-converter and a control signal converter. The micro radio converts the digital radio signals to analog RF (radio frequency) signals and vice versa and is connected to the internal bus. At least one antenna element is connected to the micro radio and an internal data bus for the exchange of digital radio data and control data is connected to micro radio and hub. By placing two or more modules next to each other on a frame these modules form an active antenna system.

Abstract: A mobile wireless communications device may include an antenna, LTE RF differential inputs, and a front end circuit. The front end circuit may include band pass filters coupled to the antenna, LNAs coupled respectively to the band pass filters, and RF switching circuits. Each RF switching circuit may be respectively coupled between each LNA and a pair of LTE RF differential inputs and configured to switch to one or both of the pair of LTE RF differential inputs.

Abstract: A transceiver includes a first circuit having a connector for connection to an antenna and receiving circuitry, and a second circuit having transmitting circuitry. The first and second circuits are coupled using a balun, where the balun is arranged so that its unbalanced side is in the first circuit and its balanced side is in the second circuit.

Abstract: A transceiver module and duplexer within a communication device supports a minimized antenna volume and enhances a transfer gain for transmit and receive channels. The duplexer is communicatively coupled to one of multiple antenna and filter matching configurations which include a first configuration that couples receive and transmit filter matching circuits to a single antenna matching circuit. When the duplexer is coupled to the first configuration, receive and transmit filters of the duplexer are respectively coupled to the receive filter matching circuit and the transmit filter matching circuit. As a result, the antenna matching circuit and the filter matching circuits collectively provide the enhanced transfer gain.