Abstract: A wireless communication module for engaging in communications with a base station, the wireless communication module being incorporated into an information device having an antenna, includes a transmitter, a transmission power being controlled by the base station; variable impedance matching section arranged between an antenna connector connected to the antenna and the transmitter, which adjusts an impedance by changing a matching parameter for the variable impedance matching section; transmission power detector for detecting the transmission power; and a controller for adjusting the matching parameter based on the detected transmission power of the transmitter detected by the transmission power detector.

Abstract: A wireless terminal for use in the transmitting and receiving frequency bands of a frequency duplex system comprises transmitting and receiving stages (Tx, Rx) and signal propagating means (22, 24, 26) coupled to the transmitting and receiving stages. The signal propagating means comprises a narrow band antenna structure (24), such as a Planar Inverted-F Antenna (PIFA), having sufficient bandwidth to cover the larger one of the transmitting and receiving frequency bands and a BAW receiving filter (26) and a BAW transmitting filter (22) coupled by respective feeds to the antenna structure (24). The filters (22, 26) enable the antenna structure to have a small volume and be reusable at different FDD frequencies.

Abstract: A signal interface includes a dual-drive device having a first and a second input port that receive an outgoing signal. One of the first and the second input ports also receive an incoming signal. The dual-drive device passes the incoming signal to an output port while isolating the outgoing signal from the incoming signal.

Abstract: An integrated radio circuit includes a receiver section, a transmitter section, an analog to digital converter section, a digital to analog converter section, a digital baseband processing module, a first dual function input/output (I/O) module, and a second dual function I/O module. The first dual function input/output (I/O) module is operably coupled to provide inbound digital baseband signals as selected inbound digital baseband signals to the digital baseband processing module when the integrated radio circuit is in a normal mode of operation and to provide test inbound digital baseband signals as the selected inbound digital baseband signals to the digital baseband processing module when the integrated radio circuit is in a test mode.

Abstract: A mobile phone with wireless camera detection. A mobile phone converts the frequency band of a received signal to mobile signal frequency band (for example GSM, DSC or PCS) with added mixer, oscillator, and filter. The converted signal is treated as a mobile signal prior to processing in the base band processor. Detected signal strength is checked to determine whether a wireless camera is currently present.

Abstract: Systems and methods are disclosed for a wireless communications device for receiving wireless electronic signals including first wireless electronic signals at a first frequency and second wireless electronic signals at a second frequency. The wireless communications device includes an antenna adapted to convert the wireless electronic signals into input electronic signals, and an amplifier coupled to the antenna, said amplifier being capable of amplifying the input electronic signals to produce amplified electronic signals and a diplexer adapted to receive the amplified electronic signals and selectively output one of the first electronic signals at the first frequency and the second electronic signals at the second frequency.

Abstract: An approach for estimating and removing crosstalk and other interference in a communications receiver is disclosed. The approach enables crosstalk and interference of arbitrary origin and power spectral density to be removed from a received signal, thereby improving the signal to noise ratio (SNR). A receiver samples the received signal at a rate N times the required sampling rate, and splits the signal into N separate observation sequences, all at the required sampling rate. The N observation sequences are separated into a data signal and a crosstalk signal. The crosstalk signal is discarded, while the data signal is passed to equalization and demodulation circuits of the receiver.

Abstract: A receiver includes a tuner and a circuit. The tuner receives an indication of a radio frequency signal from an antenna feedline in response to the radio frequency signal being provided to the antenna feedline by an amplifier. The circuit transmits a control signal to the antenna feedline to control a gain of the amplifier in response to a strength of the radio frequency signal.

Abstract: One of objects of a wireless communication apparatus according to the present invention is to realize stable communication regardless of received signal strength indication and information amount. The wireless communication apparatus for communicating in an autonomous distributed wireless network includes a detection unit which generates a detection signal by detecting a first wireless signal from a first wireless apparatus; a wireless circuit which receives a second wireless signal relating to said first wireless signal, transmitted from a second wireless apparatus which received said first wireless signal; a signal estimation unit which estimates said detection signal and the received second wireless signal; a signal selector which selects either said detection signal or the received second wireless signal, based on an estimation result of said signal estimation unit; and a demodulator which demodulates the signal selected by said signal selector.

Abstract: A cellular phone and method for receiving and transmitting signals of different frequency bands and wireless standards utilizes an architecture that allows the use of switches that are less expensive and less lossy than switches used in comparable cellular phones. The architecture also allows the use of only narrow-banded antennas, rather than a combination of a narrow-banded antenna and a harmonic antenna. As a result, the performance of the cellular phone can be significantly improved.

Abstract: A transmit-receive (T/R) switch for coupling a TDD transceiver to an antenna. The T/R switch comprises 1) a first circulator having a first port for receiving a transmit signal from the transceiver during transmit mode, a second port for sending the transmit signal to the antenna during transmit mode and receiving a received signal from the antenna during receive mode, and a third port for sending the received signal towards the transceiver during receive mode. The T/R switch further comprises 2) a second circulator having a first port for receiving the received signal from the third port of the first circulator during receive mode and a second port for sending the received signal towards the transceiver during receive mode, and 3) a termination load coupled to a third port of the second circulator. The circulators divert RF energy reflected from the antenna during transmit mode into the termination load.

Abstract: A transponder system that integrates redundancy and beam selection capabilities is disclosed. The transponder system comprises an amplifier network having a plurality of amplifiers; an antenna network, comprising a plurality of antennae; an output switching network, including a first output switching network switch, selectably coupling one of the amplifiers to one of the plurality of antennae at a first output switching network switch first switch state and to a second output switching network switch in a first output switch network switch second switch state, wherein the second output switching network switch is selectably coupled to a second one of the plurality of antennae in a second output switching network switch first switch state and to a third one of the plurality of antennae in a second output switching network switch second switch state.

Abstract: A mobile wireless communications device may include a housing and a common antenna carried by the housing and having a plurality of spaced apart signal feed points thereon. The device may further include a plurality of wireless radio frequency (RF) transceivers carried by the housing and coupled to respective ones of the signal feed points of the common antenna. Each wireless RF transceiver may also have a respective different operating frequency associated therewith. Furthermore, the device may also include a controller selectively operating at least some of the wireless RF transceivers to advantageously use the common antenna at a same time.

Abstract: A wireless communication device that is attached or included in an electronic object, such as a portable computer, having its own separate communication system. The separate communication system has an antenna for receiving and transmitting wireless communications, and is powered by a power supply included in the object. Since the separate communication system can only communicate when powered, a separate passive wireless communication device is provided for wireless communication that does not require power from the power supply to communicate. The wireless communication device is interfaced with the existing antenna of the separate communication system so that the wireless communication device and separate communication system share a common antenna to reduce cost. The antenna may also be interconnected to a controller associated with the object so that the controller can directly communicate to the wireless communication device.

Abstract: A device to transmit and receive data for remote control of hearing devices has a reduced size achieved by the transmitter coils of the transmitter and the receiver coil of the receiver being wound around a common, shared core. Moreover, a protective capacitor that is used to protect the receiver is at the same time used as a correction capacitor to correct the resonant frequency of a reception oscillator circuit.

Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: A receiver is protected by reducing a transmit leakage signal leaked when a transmit signal is radiated through the antenna by using three circulators (transmitter, antenna, and receiver). The transmitter and antenna circulators output the transmit leakage signal to be reduced to less than the transmit signal through a first leakage path. The transmitter and receiver circulators output the transmit leakage signal through a third leakage path and reduce the signal. The transmit leakage signals received through the first and third leakage paths are canceled, and that received through a second leakage path is output to a receiver. The transmit leakage signal has a 40 dB signal reduction compared to the transmit signal, and is transmitted to the receiver.

Abstract: A base station and a method of configuring a base station are provided in a cellular telecommunication system, wherein the base station comprises an electrically tunable duplex filter with a tuning range covering at least two parallel sub-bands used in the telecommunication system. The electrically tunable duplex filter is tunable on site to a sub-band allocated to the base station, thus enabling an increased flexibility in selecting a fixed frequency band to be used in the lower frequency stages in the transceiver and the base band parts of the base station.

Abstract: A duplexer for connection with an antenna comprises an antenna port, a transmitting filter comprising bulk acoustic wave (BAW) resonators having a first antenna side impedance coupled with the antenna port, a receiving filter comprising BAW resonators having a second antenna side impedance coupled with the antenna port, and a shunt inductance coupled between the antenna port and ground. The shunt inductance and the first and second antenna side impedances of the transmitting filter and the receiving filter are selected in such a way that the shunt inductance turns the first and second input impedance in a negative direction in a Smith diagram.

Abstract: The present invention relates to a transceiver for bidirectional frequency division multiplexed transmission, a communication system including one or more transceivers. Optionally, the communication system is a communication system for a digital subscriber line. The transceiver comprises transmission means with a voltage source output or a current source output for transmitting data in a transmission frequency range, receiving means for receiving data in a receiving frequency range, and a coupling impedance for connecting the transmission means and the receiving means to a transmission medium. The magnitude of the coupling impedance in the transmission frequency range is smaller than the magnitude of the coupling impedance in the receiving frequency range if the transmission means has a voltage source output and is higher than the magnitude of the coupling impedance in the receiving frequency range if the transmission means has a current source output.

Abstract: A high-frequency switch module is less power consumable, and is able to be small-sized and thinner in thickness. The high-frequency switch module is also able to obtain an amount of attenuation in a stopband and proper characteristics. The high-frequency switch module includes a gallium arsenide (GaAs) switch made of gallium arsenide that is less power consumable and low pass filters for respective transmission systems. A low pass filter is composed of a first inductor and a capacitor connected in series, and second and third inductors respectively connected to input and output terminals, and the second and third inductors having inductances greater than that of the first inductor.

Abstract: A transceiver 400 is provided in an ultrawide bandwidth device, which includes an antenna 110, a transmitter circuit 145, and a receiver circuit 165. A transmitter amplifier 440 is provided between the antenna 110 and the transmitter circuit 145, and is configured to have an operational transmitter output impedance when the transceiver 400 is in a transmit mode and an isolation transmitter output impedance when the transceiver 400 is in a receive mode. A receiver amplifier 460 is provided between the antenna 110 and the receiver circuit 165, and is configured to have an operational receiver input impedance when the transceiver 400 is in a receive mode and an isolation receiver input impedance when the transceiver 400 is in a transmit mode. The isolation transmitter output impedance is greater than the operational receiver input impedance, and the isolation receiver input impedance is greater than the operational transmitter output impedance.

Abstract: A multiple band antenna has an RF coupling structure (110) and a resonant RF structure (102). The RF coupling structure (110) has an RF connection (116, 118) and an RF coupling end (112, 114). The resonant RF structure (102) is reactively coupled to the RF coupling end (112, 114). The resonant RF structure (102) has a first end (106) and a second end (108) and has a conductive perimeter (102) enclosing at least one slot area (104) configured to induce an additional resonant RF band for the resonant RF structure (102). The first end (106) and the second end (108) are reactively coupled to a ground plane (124, 120) to facilitate longer wavelength operation. Cellular phones (800) and wireless communications sections incorporating such antennas are also provided.

Abstract: An antenna switch module connected to a common antenna for switching the connection of the antenna to a transmission circuit or a receiving circuit in plural transmitting/receiving systems having different passbands, comprising a diplexer circuit comprising a low-pass filter and a high-pass filter; a first switch circuit connected to the low-pass filter and for switching a transmitting line and a receiving line, a second switch circuit connected to the high-pass filter for switching a transmitting line and a receiving line; a third switch circuit connected to the first switch circuit for switching the receiving line from the first switch circuit; and a fourth switch circuit connected to the second switch circuit for switching the receiving line from the second switch circuit; at least part of transmission lines constituting LC circuits in the diplexer circuit and the first and second switch circuits being electrode patterns formed in a multilayer substrate constituted by plural dielectric layers; and chip ele

Abstract: In an input/output circuit (200), a differential balun (250) is provided that has first and second balun inputs and first and second balun outputs. An antenna (230) is connected to the first and second balun outputs. A differential amplifier (220) has one output connected to the first balun input, and a second output connected to the second balun input, while a single-ended amplifier (110) has its input connected to the first balun input. A grounding switch (240) is connected between the second balun input and ground. During a transmit mode the grounding switch (240) is open, the differential amplifier (220) is turned on, and the single-ended amplifier (110) is turned off. During a receive mode the grounding switch (240) is closed, the differential amplifier (220) is turned off, and the single-ended amplifier (110) is turned on.

Abstract: An active antenna array for use in a beamforming antenna system. The antenna array includes multicarrier power amplifiers coupled to each antenna element wherein the outputs of the multicarrier power amplifiers are linearized. The antenna array communicates with a base station control unit located at the base of the cellular tower in digital baseband. Fiber optic transmission lines couple the antenna arrays with the base station control unit. Multicarrier linear power amplifiers may be coupled to the antenna elements to linearize the outputs of the antenna elements. Alternatively, a predistortion circuit is coupled to the antenna elements to linearize the outputs of the antenna elements when multicarrier power amplifiers are used.

Abstract: In a first embodiment, the invention relates to an arrangement for operating a plurality of terminal devices (6) on a common antenna (4) with a coupling network (2) comprising a first separator (8) associated with the antenna (4) and a second separator (10) associated with the respective terminal (6). In a second embodiment, the invention relates to an arrangement for operating a plurality of terminal devices (6) on a common transmitting antenna (4?) and on a common receiving antenna (4) which is separate from the common transmitting antenna (4?) with a coupling network (2) comprising a separator (10) which is associated with the respective terminal.

Abstract: A system and method for implementing a wireless communications link between two equipment envelopes through inductive coupling include two “U” shaped inductors. Wireless communications is achieved via mutual inductance between the two inductors. Circuitry is provided, which enables the transmitter to determine if a receiver is within communications range. When the two envelopes are aligned, a dual-gap toroidal core is formed, in which the gaps have opposite polarity. The opposing polarity of the two gaps minimizes the far field signature of the transmitter/receiver pair, thus enhancing communication security.

Abstract: An apparatus and method of for attaching an antenna to a mobile communication device. The apparatus can include radio frequency generation circuitry, a radio frequency feed point coupled to the radio frequency generation circuitry, a direct current voltage source coupled to the radio frequency feed point, and an antenna detection module coupled to the radio frequency feed point and the direct current voltage source. The antenna detection module is configured to detect a type of antenna coupled to the radio frequency feed point based on a detected direct current voltage. The antenna detection module can be coupled to the radio frequency feed point and a ground contact point. The apparatus can additionally include a parameter of operation adjustment module coupled to the antenna detection module. The adjustment circuitry can be configured to adjust a parameter of operation of the mobile communication device.

Abstract: A warning system for making known the presence of an emergency vehicle. A transmitter is mounted in an emergency vehicle that outputs a digital UHF/LMS signal that is detectable within a range. A receiver responds to the digital UHF/LMS signal from the transmitter and is mounted, most preferably to a dashboard of a motor vehicle. The receiver detects from the digital signal the type of emergency vehicle from which the digital signal is originating. In one embodiment the digital signal also includes a unique identifier for the transmitter rather than simply a generic discipline identifier such as police, fire, emergency etc. A visual indicator mounted to the motor vehicle is activated in response to the digital signal from the transmitter to warn a motorist in the motor vehicle of a presence of the emergency vehicle within the range of the transmitter and to warn the transmitting vehicle of the presence of other emergency vehicles within receiving range.

Abstract: Antenna switches (1,10) in dual-band or multi-band mobile phones are according to a basic idea provided with a serial semiconductor switches (11,21,12,22) per transmitting branch (2,3) and with a further semiconductor switch (13,23) coupled in parallel to a receiving branch (4,5,6), to obtain isolation between branches (2-6) in a simple way. Said semiconductor switches are PIN diodes or MEMS switches or pHEMT switches. Another semiconductor switch (14) coupled in parallel to the receiving branches (4-6) allows together with said further semiconductor (13) the introduction of elements (15,16) without a transmission line. Alternatively, the antenna switch (1,10) may comprise a transmission line (24,25), in which case the receiving branches (4,5,6) can be switched via transistor switches (26,27,28). This all improves isolation, reduces costs, complexity, size and high Radio-Frequency (RF) losses.

Abstract: A cosite interference rejection system allows cancellation of large interfering signals with an optical cancellation subsystem. The rejection system includes an interference subsystem coupled to a transmit system, where the interference subsystem weights a sampled transmit signal based on a feedback signal such that the weighted signal is out of phase with the sampled transmit signal. The optical cancellation subsystem is coupled to the interference subsystem and a receive antenna. The optical cancellation subsystem converts an optical signal into a desired receive signal based on an interfering coupled signal and the weighted signal. The weighted signal is therefore used to drive the optical cancellation subsystem. The rejection system further includes a feedback loop for providing the feedback signal to the interference subsystem based on the desired receive signal.

Abstract: A high frequency device includes a transmission/reception amplifier 13 that amplifies and outputs an input signal, and a transmission/reception switch 2 that gang switches internally so that during transmission an input of the transmission/reception amplifier 13 is connected to an up mixer and an output of the transmission/reception amplifier 13 is connected to an antenna unit 5, and so that during reception the output of the transmission/reception amplifier 13 is connected to a down mixer and the input of the transmission/reception amplifier 13 is connected to the antenna unit 5.

Abstract: An electronic device able to detect a user in close proximity. The device may be a wireless data input device, for example, a radio frequency computer mouse. The device has power management features that do not require complex hardware or software to implement. For example, an antenna that is normally used for radio transmission is monitored. The power management features of the electronic device are able to detect a change in an operating characteristic of the antenna that is indicative of a user in close proximity thereto. For example, when the user touches a computer mouse, the resonant frequency of a circuit comprising the antenna changes due to capacitive loading of the antenna. The power management features cause the electronic device to be operated in a sleep mode or a radio transmission mode, depending on whether the user is detected.

Abstract: Transistor package leads form quarter-wave antenna elements that directly radiate RF energy into free space without the need for a separate antenna. The transistor operates at a fundamental frequency and radiates a harmonic, thereby allowing radiation at frequencies normally considered “beyond cutoff” for a packaged transistor. This technique enables an additional 20 GHz of spectrum for use by surface mount technology. The transistor may be mounted on 1.6 mm thick glass-epoxy circuit board that also forms a quarter-wave reflector at 26 GHz. An optional dielectric lens produces a narrow beam and an optional planar filter rejects spurious fundamental emissions. A 26 GHz ultra-wideband (UWB) pulse-echo radar rangefinder implementation provides a low-cost upgrade to ultrasound.

Abstract: The method and apparatus herein identifies tunable duplexer in a communication system. The tunable duplexer includes a tunable receiver filter, a tunable transmitter filter, a variable receiver phase shifter, and variable transmitter phase shifter. Each filter and phase shifter is optimized based on characteristics of impedance within the duplexer. The duplexer may be adjusted to changing environments or desired changes in the frequency of operation, reducing circuitry architecture and providing greater flexibility in communication function. The method commences by tuning tunable filters within the duplexer and then optimizing phase shifters within the duplexer for adjusting impedance matching with antenna and isolating the receiver from the transmitter during duplexing operations. Optimizations and calibration may be performed during manufacture, upon initialization of the system, or during operation of the communication device.

Abstract: Multiple power amplifiers in an RF front end are coupled to multiple antennas without diversity switching between the PAs and antennas. Diversity switches direct signals to broadcast by a selected antenna to a PA coupled to the selected antenna. Multiple LNAs are similarly coupled to the diverse antennas. Having one PA and LNA set for each antenna removes the need for diversity switching between the PA/LNAs and each antenna improving signal reception. In one embodiment, a single external PA performs broadcast functions and plural on-chip LNAs are used for reception. In another embodiment, phase shifters are coupled to each PA and LNA, which provide beam forming capability for broadcasts, and in phase signal combinations for received signals.

Abstract: A repeating apparatus and method using wireless optical transmission is disclosed. The repeating apparatus includes a donor device for transmitting two identical copies of an optical signal by receiving a RF signal from a base station and electro-optic converting the RF signal to an optical signal, and for transmitting a RF signal by receiving two identical copies of the optical signal and optic-electro converting the optical signal to a RF signal; and a coverage device for transmitting a RF signal to a mobile communication terminal by receiving two identical copies of the optical signal from the donor device and optic-electro converting the two identical copies of the optical signal to the RF signal, and transmitting two optical signals to the donor device by receiving the RF signal from the mobile communication terminal and elector-optic converting the RF signal to the optical signal.

Abstract: The invention provides a composite high frequency component constituting a part of a microwave circuit having plural signal paths corresponding to their respective frequencies, comprising: a diplexer for coupling transmitting signals from the plural signal paths for transmission and distributing receiving signals into said plural signal paths for reception; plural high frequency switches for separating the plural signal paths into a transmission section and a reception section, respectively; plural filters introduced in the signal paths; said diplexer, said high frequency switch, and said filters being integrated into a ceramic multi-layer substrate formed by lamination of plural ceramic sheet layers. According to the above described composite high frequency component, the diplexer, the high frequency switches, and the filters which constitute the composite high frequency component are integrated into the ceramic multi-layer substrate formed by lamination of plural ceramic sheet layers.

Abstract: A compact-size planar antenna uses, as a ground plane, a LCD-protective bracket of a portable wireless device with an LCD. The antenna includes a top plate spaced apart from the bracket by a predetermined distance, and a short circuit plate connected to the top plate and the bracket with both ends. A power feed line is connected to the top plate and the bracket with both ends, and a dielectric body having a high dielectric constant is arranged between the bracket and the top plate. The compact-size planar antenna is spaced apart from conductor parts of the portable wireless device by a predetermined distance, and formed at a left lower corner of the portable wireless device when viewed from back of the portable wireless device.

Abstract: The present invention provides a transceiver circuit that includes a transmission amplifier coupled with an antenna input/output node. The transmission amplifier is configured to amplify communications to be transmitted from the transceiver circuit. The transceiver circuit further includes a receiver and a field effect transistor. The receiver includes a receiver input coupled with the antenna input/output node. The field effect transistor is coupled between the receiver input and an electrical reference. The field effect transistor is configured to provide an open circuit when communications are received at the receiver input and to provide a closed circuit when communications are not being received at the receiver input.

Abstract: A multilayer diplexer has a first I/O terminal, a second I/O terminal, an antenna terminal, a high-pass filter coupled between the antenna terminal and the second I/O terminal, and a low-pass filter coupled between the antenna terminal and the first I/O terminal. The high-pass filter has a first capacitor and a second capacitor connected in serial coupled between the antenna terminal and the second I/O terminal, a fourth capacitor coupled between the antenna terminal and the second I/O terminal, and a first inductor coupled between a connection node of the first and second capacitors and a reference ground. The low-pass filter has a second inductor coupled between the antenna terminal and the first I/O terminal, and a third and fifth capacitor connected in parallel coupled between the antenna terminal and the first I/O terminal.

Abstract: An exemplary antenna switching circuit comprises first, second, third and fourth switches. The first switch is activated by a first control signal for establishing a connection between a first transmit port and an antenna; the second switch is activated by a second control signal for establishing a connection between a second transmit port and the antenna; the third switch is activated by a third control signal for establishing a connection between a first receive port and the antenna; and the fourth switch is activated by the third control signal for establishing a connection between a second receive port and the antenna. With this arrangement, the first receive port and the second receive port are simultaneously connected to the antenna when the third switch and the fourth switch are activated by the third control signal.

Abstract: A circuit arrangement for a multimode mobile telephone that transmits and receives signals to and from various mobile radio networks contains a baseband and a transceiver unit. The transceiver unit includes a digital adaptive predistorter having a switching element. The switching element is arranged so that an optional connection is created. The optional connection connects an amplifier output to an input of a receiver causing that receiver input to be disconnected from an antenna changeover switch. This way, it is possible for the receiver to be disconnected from a transmitting and receiving antenna during periods when the receiver is not receiving signals from the transmitting and receiving antenna. While the receiver is disconnected from the transmitting and receiving antenna, the receiver is able to receive other signals.

Abstract: A small-sized low-cost multiplexer with a low insertion loss includes a first filter defining a lowpass filter that passes a signal in a first frequency band and attenuates a signal in second and third frequency bands, a second filter including a SAW filter and defining a bandpass filter that passes a signal in the second frequency band and attenuates a signal in the first and third frequency bands, and a third filter defining a highpass filter that passes a signal in the third frequency band and attenuates a signal in the first and second frequency bands. One of two ports of each of the first, second, and third filters are connected in common with a common port.

Abstract: A system and method is provided for full-duplex antenna impedance matching. The method comprises: effectively resonating a first antenna at a frequency selectable first channel in a first frequency band; generating a first antenna impedance at the first channel frequency; effectively resonating a second antenna at a frequency selectable second channel in the first frequency band; generating a second antenna impedance at the second channel frequency; supplying a first conjugate impedance match at the first channel frequency; and, supplying a second conjugate impedance match at the second channel frequency. For example, the first antenna may be used for transmission, while the second antenna is used for received communications. The antennas effectively resonant in response to: supplying frequency selectable conjugate impedance matches to the antennas; generating frequency selectable antenna impedances; and/or selecting the frequency of antenna resonance.

Abstract: A system and method for providing auxiliary reception in a wireless communications system includes a wireless communications device. The wireless communications device includes a first antenna and a second antenna. The wireless communications device can, for example, establish two-way communications with a wireless communications network. The wireless communications device can also use the second antenna in at least one of a mobile assisted hand off (MAHO), a diversity antenna system and a global positioning system (GPS) system.

Abstract: To provide a high frequency switch capable of dealing with multiple frequency bands without having plurality of switch circuits. A first diode that conducts due to a bias current when a first switch is closed is interposed between first signal terminal and a second signal terminal. A strip line with the electrical length L1 is connected to the cathode of the first diode, the other end being grounded. At a position with a distance L2 from one end of the strip line, a capacitor and a second switch are connected to be equivalently grounded when the second switch is closed. The strip line resonates with the electrical length L1 when the second switch is opened, and resonates with the electrical length L2 when the second switch is closed.

Abstract: A high-frequency device includes an antenna terminal, a signal line connected to the antenna terminal, a high-frequency signal processing circuit connected to the signal line, a capacitance element having one end connected to the signal line and other end grounded, and an inductor having one end connected to the signal line and other end grounded. The high-frequency device can protect the high-frequency signal processing circuit from a high voltage noise, such as a static electricity, having a frequency close to a signal pass band.

Abstract: A compact package whose inner walls can be located near a radio frequency circuit without changing the characteristics of the radio frequency circuit has a planar circuit on the bottom of the package, which is enclosed with metal walls. A high impedance plate is formed in two dimensions on the metal plate of a lid. The high impedance plate has a dielectric sheet on which is formed a conductor sheet on which is formed a two-dimensional periodic array of right hexagonal metal patches. The high impedance plate blocks surface propagation of electromagnetic waves in a certain frequency band (band gap). The operating frequency of the planar circuit is set within the band gap, so that the lid and the planar circuit can be put close to each other with no change in the operation characteristics of the planar circuit.