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: 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 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 dual-band antenna matching system and a method for dual-band impedance matching are provided. The method comprises: accepting a frequency-dependent impedance from an antenna; and, selectively supplying a conjugate impedance match for the antenna at either a first and a second communication band, or a third and a fourth communication band. More specifically, the method comprises: tuning a first tuning circuit to a first frequency; and, simultaneously tuning a second tuning circuit to a second frequency. In response, a conjugate match is supplied to the antenna in the first communication band in response to the first frequency. Simultaneously, the antenna is matched in the second communication band in response to the second frequency. When the first tuning circuit is tuned to a third frequency, and the second tuning circuit is tuned to a fourth frequency, then conjugate matches are supplied for the third and fourth communication bands, responsive to the third and fourth frequencies, respectively.

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 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 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 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: The present invention provides a tunable bandpass filter and method thereof. In a preferred embodiment, the tunable bandpass filter uses variable ferro-electric capacitors to adjust both the passband and the notch across the normal operating range of a wireless communications device. The tunable bandpass filter is capable of providing a tuning range over a desired frequency range with low I.L. and high out-of-band rejections.

Abstract: A power amplifier matching circuit is provided. The matching circuit includes a ferro-electric tunable component. A control signal is applied to the tunable component, changing the component's impedance. This changes the impedance of the matching circuit.

Abstract: An inverted-F ferroelectric antenna is provided. The antenna comprises a counterpoise, or groundplane, and a radiator structure having a first end and a second end. A capacitor, formed from a ferroelectric dielectric is interposed between the second end of the radiator and the counterpoise. The capacitor has a variable dielectric constant, and the antenna is resonant at a frequency responsive to the dielectric constant of the capacitor ferroelectric material. Typically, the capacitor includes a dielectric formed from a fixed constant dielectric, together with a ferroelectric dielectric with a variable dielectric constant. A bias voltage feed is used to apply a voltage to the capacitor ferroelectric dielectric. The ferroelectric dielectric has a dielectric constant that varies in response to the applied voltage.

Abstract: A tunable ferroelectric component and a narrowband resonant circuit for measuring the loss of the ferroelectric component. The ferroelectric component may be a capacitor integrated in the resonant circuit. The testing method eliminates other sources of loss to isolate the loss due to the ferroelectric material and to demonstrate that this loss is low.

Abstract: A ferro-electric filter and method of tuning same. The filter includes a switch for switching between quarter wave resonator and half wave resonator modes. The filter also includes a ferro-electric component for tuning the resonant frequency. The method includes applying a switching control signal to the switch for switching between resonant frequencies and applying a tuning control signal for tuning the resonant frequency.

Abstract: A tunable low noise amplifier matching circuit is provided. The matching circuit includes a ferroelectric tunable component. A control signal is applied to the tunable component, changing the component's impedance. This changes the impedance or the noise figure response, or both, of the matching circuit.

Abstract: The present invention quantifies and reduces losses in tunable bandpass filters having ferro-electric capacitors. Given a required insertion loss and the quality factor of a resonator, the geometric losses resulting from a particular topology for the ferro-electric capacitor and the metal losses are accounted for to quantify the allowable ferro-electric losses.

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: A power amplifier matching circuit is provided. The matching circuit includes a ferro-electric tunable component. A control signal is applied to the tunable component, changing the component's impedance. This changes the impedance of the matching circuit.

Abstract: A dual-band antenna matching system and a method for dual-band impedance matching are provided. The method comprises: accepting a frequency-dependent impedance from an antenna; and, selectively supplying a conjugate impedance match for the antenna at either a first and a second communication band, or a third and a fourth communication band. More specifically, the method comprises: tuning a first tuning circuit to a first frequency; and, simultaneously tuning a second tuning circuit to a second frequency. In response, a conjugate match is supplied to the antenna in the first communication band in response to the first frequency. Simultaneously, the antenna is matched in the second communication band in response to the second frequency. When the first tuning circuit is tuned to a third frequency, and the second tuning circuit is tuned to a fourth frequency, then conjugate matches are supplied for the third and fourth communication bands, responsive to the third and fourth frequencies, respectively.

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 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.