Abstract: A duplexing system including: a duplexer; an antenna capable of transmitting and receiving electromagnetic signals; a transmitter adapted to couple electromagnetic signals to said antenna for transmission; a receiver capable of receiving electromagnetic signals; wherein the duplexer includes a first transmission line and a second transmission line, wherein a portion of said first transmission line is placed in proximity to a portion of said second transmission line, wherein one end of said first transmission line is connected to a first duplexer port coupled to said antenna and the second end of said first transmission line is connected to a second duplexer port coupled to said transmitter; and wherein one end of said second transmission line is connected to a third duplexer port coupled to said receiver and the second end of said second transmission line is coupled to ground or to a fourth duplexer port coupled to ground.

Abstract: Aspects of the subject disclosure may include, for example, a system for generating electromagnetic waves having a fundamental wave mode, and directing the electromagnetic waves to an interface of a transmission medium for guiding propagation of the electromagnetic waves. Other embodiments are disclosed.

Abstract: Communications receivers and devices are disclosed. A communications receiver includes a low noise amplifier; a multi-band transmit blocking filter having a first port connected to an output of the low noise amplifier, and an RF analog-to-digital converter having an input connected to a second port of the multi-band transmit blocking filter. The multi-band transmit filter passes the receive frequencies of a group of two or more LTE bands, where a first receive frequency range of a first band in the group and a second receive frequency range of a second band in the group are disjoint and not subsets of a receive frequency range of a third band in the group, and attenuates the transmit frequencies of at least some bands in the group by at least twenty dB.

Abstract: Certain aspects involve a wideband remote unit. The wideband remote unit can include one or more antennas and an analog-to-digital converter (“ADC”). The antenna can receive wideband signals. The wideband signals can include an uplink RF signal and a leaked downlink RF signal. The uplink RF signal can have an uplink signal power at or near a noise level. The leaked downlink RF signal can have a downlink signal power greater than the uplink signal power. The ADC can convert the received wideband signals to digital RF signals representing the uplink signal and the downlink signal. The wideband remote unit can transmit the digital RF signals to a unit of a DAS that is in communication with a base station.

Abstract: A multi-band RF multiplexer for routing transmit and receive signals in a radio RF front end. According to one aspect, the disclosure provides a multiplexer for routing transmit signals to an antenna and routing receive signals to a receiver. The multiplexer provides a first hybrid coupler having a first frequency response and a second hybrid coupler having a second frequency response. The second hybrid coupler is coupled to the first hybrid coupler by a plurality of splitters. The second frequency response complements the first frequency response to increase cancellation of two signals arriving at an output port of the second hybrid coupler from two different paths through the first and second hybrid couplers.

Abstract: The present invention concerns a front end circuit (1) which comprising a first tunable duplexer (5) comprising a first tunable RX bandpass filter (9) and a first tunable TX bandpass filter (10), wherein the first tunable duplexer (5) is configured to support a first FDD mode in a first FDD frequency band and a first TDD mode in a first TDD frequency band. Furthermore, the present invention concerns a method of operating the front end circuit.

Abstract: Communications receivers and devices are disclosed. A communications receiver includes a low noise amplifier; a multi-band transmit blocking filter having a first port connected to an output of the low noise amplifier, and an RF analog-to-digital converter having an input connected to a second port of the multi-band transmit blocking filter. The multi-band transmit filter passes the receive frequencies of a group of two or more LTE bands, where a first receive frequency range of a first band in the group and a second receive frequency range of a second band in the group are disjoint and not subsets of a receive frequency range of a third band in the group, and stops the transmit frequencies of at least some bands in the group.

Abstract: An inductor that adjust characteristics of a transmit filter circuit is disposed so that the inductor and at least one of common paths, a matching circuit, a receive filter circuit, and receive paths connected to an output terminal of the transmit filter circuit define a propagation path due to magnetic-field coupling and/or electric-field coupling. This configuration does not require the addition of a circuit device to define the propagation path. It is thus possible to improve attenuation characteristics for an RF signal outside the frequency band of a transmitting signal and to improve isolation characteristics between a transmit filter circuit and a receive filter circuit without increasing the size of a radio-frequency module.

Abstract: The disclosure includes communication circuitry with a tunable filter configured to tunably filter in a split band. In a first embodiment, communication circuitry includes a tunable filter and a first additional filter. The communication circuitry is configured to communicate within a low target band and within a high target band, wherein an exclusion band is located between the low target band and the high target band. The tunable filter is configured to filter within a low tunable band when tuned within the low tunable band, and configured to filter within a high tunable band when tuned within the high tunable band. The first additional filter is configured to filter in a first additional filter band located in an upper edge of the low target band.

Abstract: A multi-antenna system is provided. The multi-antenna system includes a first antenna, a second antenna, a tunable circuit, and a frequency-divisional circuit. The first antenna is utilized to implement signals of a first frequency band. The second antenna is utilized to implement signals of a second frequency band. The second antenna is different from the first antenna, and frequencies of the second frequency band are greater than frequencies of the first frequency band. The tunable circuit is utilized to switch the signals of the first frequency band. The frequency-divisional circuit is utilized to suppress harmonics caused by the tunable circuit.

Abstract: RF circuitry, which includes a first hybrid RF coupler, a second hybrid RF coupler, a third hybrid RF coupler, and RF filter circuitry, is disclosed. The first hybrid RF coupler provides a first main port, a first pair of quadrature ports, and an isolation port. The second hybrid RF coupler provides a second main port and a second pair of quadrature ports. The third hybrid RF coupler provides a third main port and a third pair of quadrature ports. RF filter circuitry is coupled to the first pair of quadrature ports, the second pair of quadrature ports, and the third pair of quadrature ports. The first main port, the second main port, and the third main port provide main ports of the RF triplexer. The isolation port is a common port of the RF triplexer for coupling to an RF antenna.

Abstract: Offsetting unwanted downlink interference signals in an uplink path in a distributed antenna system (DAS) is disclosed. In this regard, in one example, an interference signal offset circuit is provided in an RAU to offset interference products leaked from a downlink path to an uplink path. An offset signal generation circuit is configured to generate at least one uplink interference offset signal based on the interference products leaked from the downlink path. A signal summing circuit is configured to combine the at least one uplink interference offset signal with an uplink signal received on the uplink path, thus offsetting the interference products in the uplink signal. By providing the interference signal offset circuit in the RAU to offset the interference products on the uplink path, it is possible to provide more implementation flexibility for the RAU without degrading the uplink signal.

Abstract: A frequency demultiplexer comprising an input part (106) with an input port (101), a low pass filter (125) and a band-pass filter (108) with output ports (120, 145). The input part (106), the low-pass filter (125) and the band-pass filter (108) comprise open waveguide sections, and the band-pass filter (108) comprises gap-coupled resonators (130, 135, 140). The input part (106) and the low-pass filter (125) connect to the same resonator (130), the connection (121) of the low-pass filter (125) being at a first maximum distance (L1) from a center point (N) of the resonator and the connection (116) of the output port (101) being at a second maximum distance (L2) from said center point (N) of the resonator. The center point (N) corresponds to a wave node of a wavelength ?, where ?=2d/M, M is a positive integer value and d is the shortest end-to-end distance along the resonator.

Abstract: The invention is a compact three-port signal combiner suitable for use in a base station having two different wireless systems. The combiner is designed as a four-port network, but one of the ports is terminated with a predetermined load, thus leaving three ports for connection to user equipment. A first port (A) receives from an antenna a first input signal comprising first and second receive bands and transmits to the antenna a first output signal comprising a transmit band. A second port (R), connected to the first wireless system, outputs to the first wireless system a second output signal comprising the first and second receive bands. A third port (T\R) outputs, to the second wireless system, a third output signal comprising the first and second receive bands and receives from the second wireless system a second input signal that is to be transmitted from the first port.

Abstract: A second-signal first transmission line operates as an open stub in a state in which a second antenna terminal is open. Therefore, a first signal is attenuated that is transmitted from a branch point between a second-signal first transmission line and a second-signal second transmission line to a second communication unit through a second common transmission line. In a case in which a two-antenna communication module performs communication of the first signal and communication of a second signal at the same time by connecting a shared antenna to a first antenna terminal.

Abstract: A switching splitter and method of operating the same comprises a first port, a second port in communication with the first port and a third port in communication with the first port. A switching module is in communication with the second port and the third port. The switching module switches in response to a direct current voltage at the second port. The switching module communicates a control signal from the second port to the first port or from the third port to the first port in response the direct current voltage.

Abstract: An apparatus includes a 1×2 waveguide-based power divider. The 1×2 waveguide-based power divider includes a 1×2 waveguide coupler, two primary transmission lines, two three-port waveguide couplers, and a series. The series includes one or more secondary transmission lines. Each primary transmission line connects a corresponding output of the 1×2 waveguide coupler to a first port of a corresponding one of the three-port waveguide couplers. The series connects a second ports of the three-port waveguide couplers.

Abstract: A multiple beam integrated antenna system for a satellite including a support structure having an alignment plate. The antenna system further includes a plurality of feed horns mounted to the alignment plate, where each feed horn includes a plurality of tapered sections that support propagation modes for both up-link signals and down-link signals. A septum polarizer is mounted to an input end of each feed horn that converts linearly polarized signals to circularly polarized signals for the up-link signals and converts circularly polarized signals to linearly polarized signals for the down-link signals. A Y-shaped waveguide is coupled to each of the polarizers and includes separate receive reject and transmit reject filters so as to keep the up-link signals and the down-link signals from interfering with each other. Flex waveguides couple the transmit leg and the receive leg of each Y-shaped waveguide to RF modules.

Abstract: An artificial dielectric resonator that can enhance a relative dielectric constant in a basic mode is provided. The artificial dielectric resonator 1 has a first series metal strip group 2 including a plurality of metal strips 20 each in a thin sheet shape arranged with microscopic gaps 20G provided in a longitudinal direction, and a second series metal strip group 3 including a plurality of metal strips 30 each in a thin sheet shape arranged with microscopic gaps 30G provided in a longitudinal direction, the first series metal strip group 2 and the second series metal strip group 3 are disposed close to each other in a thickness direction of the metal strips 20 and 30, and the metal strip 20 or 30 of one metal strip group 2 or 3 is disposed to face and cross gap 30G or 20G of the other metal strip group 3 or 2.

Abstract: An ‘L’ shaped dynamically configurable impedance matching circuit is presented herein. The circuit can include a series element and a shunt element. The shunt element in the L-shaped impedance matching circuit can be moved or modified based on the impedance of the circuit elements in electrical communication with each side of the impedance matching circuit. Thus, in some cases, the impedance matching circuit may be a flexible circuit that can be dynamically modified based on the environment or configuration of the wireless device that includes the impedance matching circuit.

Abstract: A high frequency circuit module includes a variable inductance circuit portion and a reactance circuit portion. The variable inductance circuit portion is connected between an antenna port and ground. The variable reactance circuit is connected between the antenna port and a front-end port. The variable inductance circuit portion includes a first inductor, a second inductor, and a switch. The first inductor is connected between the antenna port and the ground. The second inductor and the switch are connected in series, and this series circuit is connected in parallel to the first inductor.

Abstract: Various embodiments relate to an apparatus and related method for transmission and reception of a plurality of a carrier signals comprising one or more dual-band channels through a same-band combiner. A device such as a base station may include a same-band combiner that comprises a plurality of dual-bandpass filters and a combining element to transmit and receive the carrier signal. Each of the dual-bandpass filters may transmit and receive a channel, with each dual-bandpass filter including separate reception and transmission passbands for the separate frequencies in the dual-band channel. The combining element may separate and combine the one or more dual-band channels, with each of the dual-bandpass filters connected in parallel processing separate dual-band channels.

Abstract: A tunable impedance network and a method for tuning the tunable impedance network are disclosed. In one aspect, the tunable impedance network comprises a plurality of transformers connected in series. Each transformer has a primary winding and a secondary winding. The transformers have a voltage transformation ratio of N:1 with N>1. An impedance structure, acting as a resonant circuit together with the inductance of the secondary winding, is connected at the secondary winding of each transformer. A control circuit or processor is configured to tune the imaginary part of at least one of the impedance structures so as to change its resonance frequency to mimic a reference impedance. The control circuit is further configured to tune the real part of at least one of the impedance structures so as to change its Q-factor to mimic the reference impedance.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include cavity antennas. A cavity antenna may be formed from a metal antenna cavity and resonating element structures. The metal antenna cavity may be formed from metal traces on a dielectric carrier. The resonating element structures may include directly fed and indirectly fed slot antenna resonating elements and monopole antenna resonating elements. The metal antenna cavity may exhibit a resonance that is tuned using a transmission line tuning stub. Filters and duplexer circuits may be used in routing signals at different frequency bands among the antenna resonating elements.

Abstract: Systems, methods, and computer-readable media, for facilitating identification of antenna ports. In some embodiments, the method includes receiving a test signal transmitted through a physical path to an antenna port. Upon receiving a test signal, a response can be provided that includes an indication of the antenna port that received the test signal. Such a response signal can be provided in any number of manners.

Abstract: A device, apparatus, and method are provided for mitigation of return loss during signal transmission. The device comprises a radio transmitter and a radio antenna coupled by a signal transmission line, the radio antenna configured to broadcast over air a radio signal transmitted by the radio transmitter, the signal transmission line configured to transmit the radio signal to the radio antenna along a signal path. The device further comprises a positioning stub coupled to the radio transmitter, the radio antenna, and the signal transmission line, the positioning stub configured to move to different locations along the signal path to dynamically change the impedance of the signal path to reduce signal return loss.

Abstract: A dual band antenna configuration constituted of: a waveguide extending from a proximal section to a high frequency band section; a first high frequency band port extending from the high frequency band section of the waveguide; a first low frequency band port extending, from an outer surface of a low frequency section of the waveguide, along a first radial path; a second low frequency band port extending, from the outer surface of the low frequency section of the waveguide, along a second radial path, the second radial path orthogonal to the first radial path; and a 180 degree hybrid coupler, wherein a first port of the 180 degree hybrid coupler in electrical communication with the first low frequency band port and a second port of the 180 degree hybrid coupler, different than the first port thereof, in electrical communication with the second low frequency band port.

Abstract: An apparatus includes an antenna, a first transceiver circuit, a second transceiver circuit, a first filter coupled between the antenna and the first transceiver circuit and configured to pass a first signal and attenuate a second signal, and a second filter coupled between the antenna and the second transceiver circuit and configured to pass the second signal and attenuate the first signal. The first signal has a first frequency and the second signal has a second frequency. The first transceiver circuit, the second transceiver circuit, and the first filter are integrated in a system on chip (SOC).

Abstract: A multi-band multi-path receiving and transmitting device and method, and a base station system are provided. The multi-band multi-path receiving and transmitting device includes a broadband antenna, at least two multi-frequency couplers, a multi-band transceiver, and a signal processing module. The multi-band transceiver is adopted to decrease the number of the transceivers, thereby reducing the material cost and the mounting cost of the base station system.

Abstract: A power division and recombination network with internal signal adjustment (“PDRN”) is described. The PDRN may include a means for dividing an input power signal having a first amplitude value into eight intermediate power signals, where each intermediate power signal has an intermediate amplitude value equal to approximately one-eighth the first amplitude value. The PDRN may also include a means for processing the intermediate power signals and a means for combining the intermediate power signal into a single output power signal.

Abstract: A front-end circuit includes an RFIC, an antenna, N duplexers, N variable impedance adjustment circuits, a switch for selecting any two of the N variable impedance adjustment circuits, and a control unit which receives a control signal from the RFIC, where 2?N. The control unit executes switching operations of the N variable impedance adjustment circuits and the switch in accordance with control information. The control signal indicates to 1) control the switch to select two variable impedance adjustment circuits corresponding to a p-th frequency band and a q-th frequency band respectively, 2) control a variable impedance adjustment circuit corresponding to the p-th frequency band to increase input impedance in the q-th frequency band as viewed from the antenna side and 3) control a variable impedance adjustment circuit corresponding to the q-th frequency band to increase input impedance in the p-th frequency band as viewed from the side.

Abstract: A concentric feed is provided. The concentric feed includes an outer-conductive tube electrically connected at a base of an inner-conductive tube to an outer-conductive tube by a process comprising the steps of: configuring the outer-conductive tube; configuring the inner-conductive tube; and positioning the outer-conductive tube to contact the inner-conductive tube at the base. The outer-conductive tube is configured to include: a side-port; a first-edge surface; a first-interior surface sharing an edge with and perpendicular to the first-edge surface; a second-edge surface; and a second-interior surface sharing an edge with and perpendicular to the second-edge surface. The inner-conductive tube is configured to include: the base at a base-end of the inner-conductive tube, the base including a first lip and a second lip protruding orthogonal to a first surface and a second surface, respectively, and a central-port centered on the central axis and parallel to the central axis; and a main-body.

Abstract: A module includes: a diplexer that includes a first terminal, a second terminal, and a common terminal coupled to an antenna; a first switch that is coupled to the first terminal, includes first ports, and selects, from the first ports, and connects one port to the diplexer; a first duplexer that is coupled to at least one of the first ports; a second duplexer that is coupled to the second terminal and has a passband different from a passband of the first duplexer; and a first impedance portion that is coupled to another port of the first ports.

Abstract: The present invention relates to a public cavity input multiplexer that is used to divide broadband signals into multi-channel narrowband signals according to the frequency and includes a public cavity and at least two channel filters. The public cavity is a broadband resonator that is used to input broadband signals, and is coupled with each of the channel filters respectively. In the input multiplexer of the present invention, no electric cable or waveguide and circulator are used for connection. The integrated design is achieved by establishing the public cavity and the channel filter, which reduces volume and mass, avoids the errors caused by influence on the circulator due to temperature change, enhances reliability, saves cost, and improves the electric performance. The design of the public cavity makes the input coupling accurate to calculate, convenient tuning and optimizes the consistency of channels.

Abstract: There is provided a splitter circuit means for use with a CATV network comprising a signal input (34) in communication with a transformer or balun (32) to supply two signal outputs (36, 38), with a resistor (52) connected in parallel between the outputs (36, 38) and wherein additional capacitive, inductive and resistive elements (48, 50, 52, 54) are associated with the resistor (42), thereby to give an insertion loss in to out in the range of 3 to 10 dB and isolation 10 out to out of <17 dB for signal frequencies in the range 1125 MHz to 1700 MHz, while at the same time maintaining good RF performance in the frequency range 5 MHz to 1000 MHz.

Abstract: A multi-band multi-path receiving and transmitting device and method, and a base station system are provided. The multi-band multi-path receiving and transmitting device includes a broadband antenna, at least two multi-frequency couplers, a multi-band transceiver, and a signal processing module. The multi-band transceiver is adopted to decrease the number of the transceivers, thereby reducing the material cost and the mounting cost of the base station system.

Abstract: A multi-band multi-path receiving and transmitting device and method are provided. The multi-band multi-path receiving and transmitting device includes at least two multi-frequency couplers, a multi-band transceiver, and a signal processing module. The multi-band transceiver includes at least two first frequency band receiving branches and at least two second frequency band receiving branches, and the multi-band transceiver is adopted to decrease the number of the transceivers, thereby reducing the material cost and the mounting cost of the base station system.

Abstract: In an example embodiment, an in-phase H-plane T-junction can comprise: a first waveguide port; a second waveguide port; a third waveguide port, wherein the third waveguide port can be a common port; and an E-plane septum. The first, second, and third waveguide ports can be in the H-plane and can be each connected to each other in a T configuration. The T-junction can be configured such that microwave signals in a first band can be in-phase with each other at the first and second waveguide ports, and microwave signals in a second band can be in-phase with each other at the first and second waveguide ports. The H-plane T-junction can be at least one of a power combiner and a power divider.

Abstract: In one embodiment, front end circuitry for an electronic appliance, the front end circuitry comprising: a first port configured to conduct signals from a signal source, the signals comprising a first signal and a second signal; a first filter coupled to the first port, the first filter configured to filter the first signal according to a first frequency band and output the filtered first signal for further processing; a second filter coupled to the first port and arranged in parallel with the first filter, the second filter configured to absorb the second signal according to a second frequency band that is a stopband for the first filter; and an impedance load coupled between an output of the second filter and ground.

Abstract: A cascaded diplexer to create a cascaded diplexer leg with selectable passbands has a cascaded diplexer circuit. The diplexer circuit has a plurality of first bandpass filters, each having a passband. The diplexer circuit has a second bandpass filter having a passband and two terminals, coupled in series with a first bandpass filter. First and second switches are coupled in series with the second bandpass filter and the first bandpass filter, the first and second switches being configured to selectably switch the second bandpass filter into the circuit. The passband of the second bandpass filter is chosen to limit the passband of the first bandpass filters, such that when the second bandpass filter is switched into the circuit, the passband of the diplexer leg is reduced. The passband of the second bandpass filter may be a subset of, or overlaps with, the passband of the first bandpass filter.

Abstract: A multiplexer includes a microstrip manifold, and a filter bank having at least two output filters. The multiplexer channelizes an input radio frequency (RF) band of electromagnetic energy into a set of output channels by way of the filter bank. The microstrip manifold has an input port that receives an input RF signal, and at least two output ports. The microstrip manifold distributes the input RF signal to each output port, each said output port being coupled to a respective one of the at least two output filters. The multiplexer may be an input multiplexer for a spacecraft communications payload system.

Abstract: The present invention relates to a signal directing means for dividing or combining signals. It comprises a bottom row first port, a first row first and second port, and a bottom row signal connector. The signal directing means further comprises a first row first and second amplifier, each first row amplifier having a corresponding first and second terminal, said first terminals being connected along the bottom row signal connector. The signal directing means also comprises a first row signal connector, where said second terminals are connected along the first row signal connector. The second terminal of the first row first amplifier is connected to the first row first port and the second terminal of the first row second amplifier is connected to the first row second port. A plurality of second connector ports are also provided, with connecting impedances connecting between the respective ports.

Abstract: This invention provides a novel electronically tunable active duplexer for wireless transceiver applications. It relates to an active duplexer with full-duplex operation, permitting simultaneous transmission and reception of signals at same or different frequencies. Instead of incorporating fixed or mechanically adjustable capacitors, and even instead of incorporating varactor diodes, it incorporates one or more capacitance tuning circuit in phase shifting networks enabling one to electronically tune, with ease and precision, the frequency at which isolation is desired, over a band in both transmit and receive modes of operations.

Abstract: An RF bandpass filter includes a cascaded series of a first subfilter and a second subfilter. Each subfilter includes a respective inverter, voltage-controlled capacitor and inductor. A first selected one of the first subfilter and the second subfilter is a pseudo low pass filter and a second selected one of the first subfilter and the second subfilter is a pseudo high pass filter. The RF bandpass filter is configured to separately control a bandwidth and center frequency of output RF energy. The bandwidth may be controlled to be substantially fixed over a significant substantial range. The center frequency and bandwidth are controlled by adjusting a voltage input to one or more of the voltage-controlled capacitors.

Abstract: A six-port circuit (100) with two input ports and four output ports, comprising a balun (110) for converting signals at one input port into first (112) and second (113) balanced signals, and a filter (105), with first and second input ports and four output ports as the four output ports of the circuit. The six-port circuit also comprises a splitter (120) for splitting second input signals at the other input port into first (121) and second (122) parts. The input ports (V?in1, V?in2) of the filter (105) are connected so that one of the balanced signals (112) and one of the parts (121) of the second input signals are connected to one of the filter's input ports (V?in1), and the other of the balanced signals (113) and the other (122) of the parts of the second input signals are connected to the other of the filter's input ports (V?in2).

Abstract: A duplexer includes a package substrate having layers stacked, a transmission filter and a reception filter that are provided on an upper surface of a first layer that is one of the layers of the package substrate, the transmission and reception filters being acoustic wave filters, a metal pattern provided on the upper surface of the first layer and formed to surround the transmission and reception filters, a transmission line provided on an upper surface of a second layer that is one of the layers of the package substrate and is positionally lower than the first layer, the transmission line electrically connecting the transmission filter and a transmission terminal together, and a reception line that is provided on the upper surface of the second layer and electrically connects the reception filter and a reception terminal. The thickness of the first layer is greater than that of the second layer.

Abstract: A circuit for a low-loss electrical balance duplexer (EBD) with noise cancellation may include an EBD circuit. The EBD circuit may be coupled to one or more output nodes of a transmit (TX) path, an antenna, and a one or more input nodes of a receive (RX) path. The EBD circuit may be configured to isolate the TX path from the RX path, and to provide low-loss signal paths between the one or more output nodes of the TX path and the antenna. A balancing network may be coupled to the EBD circuit and configured to provide an impedance that matches an impedance associated with the antenna. A noise cancellation circuit may be configured to sense a noise signal generated by the balancing network, and to use the sensed noise signal to improve a signal-to-noise ratio (SNR) of the RX path.

Abstract: A filter circuit includes a filter part connected between an input terminal and an output terminal and configured to have a passband, and a path connected in parallel with the filter part between the input terminal and the output terminal, the path having an impedance that enables a first signal passing through the path from the input terminal to the output terminal and a second signal passing through the filter part from the input terminal to the output terminal to have an opposite phase relationship in a frequency band outside of the passband and have almost equal amplitudes in the frequency band.

Abstract: A millimeter waveband filter is provided with a resonator formed by a pair of electric wave half mirrors in a transmission line of a waveguide allowing electromagnetic waves in a predetermined frequency range of a millimeter waveband to propagate in a TE10 mode, and allows frequency components centering on the resonance frequency of the resonator to pass therethrough. A high-pass filter which has a transmission line reduced in size so as to have a cutoff frequency matching an upper limit of a lower rejection band of a filter passband is formed in a transmission line between the end of the waveguide and the electric wave half mirror, thereby increasing the attenuation of the lower rejection band.

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.