Abstract: A ferro-electric (FE) tunable antenna matching circuit is provided for a multi-band antenna. The tunable matching circuit is integrated with a diplexer on one substrate. The tunable matching circuit has a first and second inductor coupled to the antenna. The second inductor is couple to a first capacitor and a second capacitor. One side of the second capacitor forms an input/output port for connection to a duplexer. One or more of the matching circuit elements is a ferro-electric (FE) tunable component.

Abstract: A mobile station with a tunable duplexer is disclosed. The mobile station includes a processor and memory in electronic communication with the processor. The mobile station includes a receive path that has a receive band reject filter in electronic communication with an antenna at a common node. The receive path also includes a receive band pass filter in electronic communication with the receive band reject filter. The mobile station includes a transmit path that has a transmit band reject filter in electronic communication with the antenna at the common node. The transmit path also includes a transmit band pass filter in electronic communication with the transmit band reject filter.

Abstract: A tunable SAW resonator circuit is disclosed. The tunable SAW resonator circuit includes a SAW resonator having a Q, a resistor coupled to the SAW resonator to reduce the Q, and a tuning component coupled to the SAW resonator to tune the SAW resonator. A method to tune the SAW resonator is also disclosed. The SAW resonator may be tuned by applying a control signal to the tuning component.

Abstract: A multi-band handheld communications device includes a transceiver including a transmitter having a transmit filter and a receiver having a receive filter, each of the transmit and receive filters having a bandpass region tunable across multiple bands, and a processor configured to select one of the multiple bands to operate the handheld communications device, and tune each of the transmit and receive filters based on the selected one of the multiple bands.

Abstract: A tunable bandpass filter includes at least one resonator having a reactance with a resonant frequency, a ferroelectric film having a dielectric constant with a value that changes with an applied electric field, and an electric field generating device for generating relatively constant electric fields of different strengths. The ferroelectric film is electrically coupled to the resonator so that the reactance of the resonator and therefore the resonant frequency of the resonator and the passband of the filter depends on the dielectric constant of the ferroelectric film. The electric field generating device is constructed and arranged to generate relatively constant electric fields within the ferroelectric film, thereby making the resonant frequency of the resonator and the passband of the filter a function of the strength of the relatively constant electric field.

Abstract: Systems and techniques for adaptive interference filtering in a communications device are disclosed. The communications device may include a transmitter, a receiver, a duplexer coupled to the transmitter and the receiver, and an adaptive filter disposed between the duplexer and the receiver. A processor may be configured to monitor cross modulation in the receiver between transmitter leakage through the duplexer and a jammer, and adapt the filter to vary its transmit signal rejection as a function of the cross modulation.

Abstract: A constant-gain phase shifter is provided, comprising a first tank circuit with a first node to accept an input signal, a first inductor connected between the first node and a reference voltage, and a first capacitor connected in parallel with the first inductor. The first tank circuit modifies the phase and the insertion loss associated with the input signal. A variable gain circuit has as input connected to the first node, an input to accept a control signal, and an output to supply a gain-modified signal. A second tank circuit comprises a second node connected to the variable insertion loss circuit output to supply a constant-gain phase-shifted signal, a second inductor connected between the second node and the reference voltage, and a second capacitor connected in parallel with the second inductor. The second tank circuit modifies the phase and insertion loss associated with the gain-modified signal.

Abstract: A tunable bandpass filter is provided that comprises a first shunt-connected ferroelectric (FE) tunable tank circuit having a first node to accept an input signal. A second shunt-connected FE tunable tank circuit has a second node to supply a bandpass filtered signal. A first capacitor is connected in series between the first and second nodes. In one aspect, the first tank circuit comprises a first resonator connected to the first node, and a fourth capacitor connected between the first resonator and a reference voltage. The fourth capacitor is a tunable FE capacitor. Typically, a fifth capacitor is connected between the first node and the reference voltage. Likewise, the second tank circuit comprises a second resonator connected to the second node, and a sixth (FE) capacitor connected between the second resonator and the reference voltage. A seventh capacitor is connected between the second node and the reference voltage.

Abstract: The present invention provides for low loss tunable matching circuits at rf frequencies. Ferro-electric materials are used to produce low loss tunable capacitors and inductors for use in matching circuits.

Abstract: A ferro-electric tunable duplexer is provided, integrated with one or more of the following parts: a power amplifier, an isolator, a duplexer, a low noise amplifier and an antenna matching circuit. More specifically, in addition to adding F-E tunability, one or more of the above components is integrated with the duplexer on one substrate. The components are integrated on one substrate either by placing each component, with the appropriate matching circuit directly on the substrate, or by direct fabrication of the component and matching circuit into or onto the substrate.

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: An apparatus and method are presented for combining electrical signals. The apparatus includes a phase-shift distributed element with an input to accept a first signal and an output to supply the first signal with a phase-shift; and a filter with a first signal port connected to the phase-shift element output, a second signal port to accept a second signal, and a third signal port to supply combined and filtered first and second signals. The phase-shift element has a signal path with a predetermined length and the phase-shift element output supplies the first signal with a phase angle shift responsive to the length of the signal path. In one example, the phase-shift element is formed from monoblock and coaxial elements, either singly or in combination, and is a tank circuit resonator in the filter.

Abstract: A family of FE dielectric-tuned antennas and a method for frequency tuning a wireless communications antenna are provided. The method comprises: forming a radiator; forming a dielectric with ferroelectric material proximate to the radiator; applying a voltage to the ferroelectric material; in response to applying the voltage, generating a dielectric constant; and, in response to the dielectric constant, communicating electromagnetic fields at a resonant frequency. Some aspects of the method further comprise: varying the applied voltage; and, modifying the resonant frequency in response to changes in the applied voltage. Modifying the resonant frequency includes forming an antenna with a variable operating frequency responsive to the applied voltage. Alternately stated, forming an antenna with a variable operating frequency includes forming an antenna with a predetermined fixed characteristic impedance, independent of the resonant frequency.

Abstract: The present invention provides a phase shifting filter and a phase compensating direct downconversion receiver. A DC offset detector detects a DC offset in a received baseband signal and provides a feedback signal. A tunable filter phase shifts a local oscillator signal responsive to the feedback signal. The phase-shifted local oscillator signal is used to directly downconvert a received RF signal, whereby DC offset in the resulting baseband signal is reduced.

Abstract: A sub-band antenna matching method and an antenna matching system for selectively matching a communication bandwidth segment impedance have been provided. The method comprises: accepting a frequency-dependent impedance from an antenna; and, selectively supplying a conjugate impedance match for the antenna at a sub-band of a first communication band. In some aspects, the method selectively supplies a conjugate impedance match for the antenna at a sub-band of a second communication band. More specifically, the method comprises: tuning a first tuning circuit to a first frequency; simultaneously tuning a second tuning circuit to a second frequency to match the antenna at a low end of the first communication band. Likewise, the first tuning circuit is tuned to a third frequency and the second tuning circuit is tuned to a fourth frequency to match the antenna at a high end of the first communication band in response to the third and fourth frequencies.

Abstract: A system and method are presented for transceiving Time Division Multiple Access (TDMA) telephone communications through a common filter. The system includes a tunable ferro-electric bandpass filter (FE BPF), a controller, a low noise amplifier (LNA), and a power amplifier (PA). The FE BPF has a control input to accept tuning voltage signals from the controller and two signal ports. In response to the tuning voltage signals, the FE BPF selects a transmit or receive frequency passband between the signal ports. The FE BPF first signal port is connected to the LNA and the PA and the FE BPF second signal port is connected to an antenna in a wireless device. The LNA and PA are activated and deactivated in response to control signals from the controller.