Abstract: RF communication systems with interference cancellation for coexistence are provided herein. In certain embodiments, a method of interference cancellation includes filtering a radio frequency (RF) transmit signal to generate a first RF feedback signal using a first filter of a front end system, filtering the RF transmit signal to generate a second RF feedback signal using a second filter of the front end system, processing the first RF feedback signal to generate a first digital interference cancellation signal using a first feedback receiver, processing the second RF feedback signal to generate a second digital interference cancellation signal using a second feedback receiver, and compensating an RF receive signal for interference based on the first digital interference cancellation signal and the second digital interference cancellation signal using a receiver.

Abstract: Aspects of this disclosure relate to acoustic wave devices on stacked die. A first die can include first acoustic wave device configured to generate a boundary acoustic wave. A second die can include a second acoustic wave device configured to generate a second boundary acoustic wave, in which the second die is stacked with the first die. The first acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode on the piezoelectric layer, and high acoustic velocity layers on opposing sides of the piezoelectric layer. The high acoustic velocity layers can each have an acoustic velocity that is greater than a velocity of the boundary acoustic wave.

Abstract: Apparatus and methods for diplexing by antenna structure are provided. In certain embodiments, a mobile device includes a front end system and an antenna structure. The front end system includes a first signal conditioning circuit configured to condition a first radio frequency signal of a first frequency, and a second signal conditioning circuit configured to condition a second radio frequency signal of a second frequency that is lower than the first frequency. The antenna structure is configured to diplex the first radio frequency signal and the second radio frequency signal, and includes a first antenna configured to handle the first radio frequency signal and a second antenna electromagnetically coupled to the first antenna and configured to handle the second radio frequency signal.

Abstract: An acoustic sensor (e.g., for use in a piezoelectric MEMS microphone) includes a substrate and a cantilever beam attached to the substrate. The cantilever beam has a proximal portion attached to the substrate and extending to a distal tip at a free end of the beam. The cantilevered beam has a width in plan view that is greater at a location distal of the proximal portion than at the proximal portion attached to the substrate. One or more electrodes are disposed on or in the proximal portion of the beam.

Abstract: A piezoelectric sensor (e.g., for use in a piezoelectric MEMS microphone) includes a substrate and a cantilever beam attached to the substrate. The cantilever beam has a proximal portion attached to the substrate and extending to an unsupported distal end. An electrode is disposed on or in the proximal portion of the beam and has an outer boundary with a shape substantially corresponding to a contour line of a strain distribution plot for the cantilever beam resulting from a force applied to the cantilever beam.

Abstract: In one example, a remote tuner module includes: a first tuner to receive, process and demodulate a first radio frequency (RF) signal to output an analog audio signal, and to receive and process a second RF signal to output a first downconverted modulated signal; a second tuner to receive and process the second RF signal to output a second downconverted modulated signal; a demodulator circuit coupled to the first and second tuners to demodulate and link the first and second modulated signals, to output a linked demodulated signal. The remote tuner module may further include a gateway circuit coupled to at least the demodulator circuit to output the analog audio signal and the linked demodulated signal.

Abstract: Aspects of this disclosure relate to bandpass filters with enhanced out of band rejection. The bandpass filters include a stage that is modified using a network of three inductors two of which are mutually coupled inductors. Related methods, radio frequency systems, radio frequency modules, and wireless communication devices are also disclosed.

Abstract: Aspects of this disclosure relate to bandpass filters with enhanced out of band rejection. The bandpass filters include a stage that is modified using a network of three inductors two of which are mutually coupled inductors. Related methods, radio frequency systems, radio frequency modules, and wireless communication devices are also disclosed.

Abstract: Programmable voltage regulators for powering multiple circuit blocks are disclosed. In certain embodiments, a front end system includes a plurality of circuit blocks, and a programmable low dropout regulator that generates a programmable regulated voltage for the plurality of circuit blocks based on a first multi-bit control signal. The programmable low dropout regulator includes a controllable frequency compensation circuit controlled by a second multi-bit control signal and operable to control a phase margin of the programmable low dropout regulator, and an overshoot control circuit controlled by a third multi-bit control signal and operable to control an overshoot of the programmable regulated voltage.

Abstract: Apparatus and methods for antenna arrays for beamforming are disclosed. In certain embodiments, a mobile device includes a front-end system including a plurality of radio frequency signal conditioning circuits, an antenna array including a plurality of controllable antennas each connected to a corresponding one of the plurality of radio frequency signal conditioning circuits, and a control circuit. The plurality of controllable antennas include a first controllable antenna including a plurality of antenna elements interconnected by a plurality of variable resistors. Additionally, the control circuit is configured to control the plurality of variable resistors to control an antenna characteristic of the first controllable antenna.

Abstract: In some embodiments, a system can include a first stream to be opened with an arbiter device, the first stream associated with a first set of capabilities, a second stream to be opened with the arbiter device, the second stream associated with a second set of capabilities, and a wireless network architecture that determines a network messaging schedule based on the first set of capabilities and the second set of capabilities. The network messaging schedule can be sent to one or more client devices associated with the first stream or the second stream.

Abstract: A system for controlling a high-power drive device includes a fault detection integrated circuit product configured to provide an indication of a fault condition associated with the high-power drive device to a first terminal in a first voltage domain in response to detecting the fault condition in a second voltage domain. The system includes a gate driver controller integrated circuit product configured to drive a second terminal coupled to a control node in a second voltage domain based on a control signal and an enable signal received from a third terminal in the first voltage domain. The second voltage domain is higher than the first voltage domain. The system may include a redundant fault reporting integrated circuit product or an additional fault detection integrated circuit product configured to detect a second fault condition in the second voltage domain that is different from the fault condition.

Abstract: Bias schemes for cascode power amplifiers are disclosed. In certain embodiments, a power amplifier system includes a cascode power amplifier powered by a first supply voltage and that amplifies a radio frequency input signal, and a bias circuit including a voltage regulator that generates a regulated voltage and is powered by the first supply voltage. The bias circuit further includes a bias voltage generation circuit that receives the regulated voltage and generates at least one cascode bias voltage for the cascode power amplifier, a switch that gates a second supply voltage to generate a gated supply voltage, a bias current generation circuit that controls a bias current of the cascode power amplifier and is powered by the gated supply voltage, and a gating circuit that controls the switch based on the regulated voltage and the second supply voltage.

Abstract: Circuits, devices, and methods related to setting a drive power of a power amplifier to a first power level, switching an input of the power amplifier to an isolation state, switching an antenna selection state of an antenna network, and switching the input of the power amplifier to an active state.

Abstract: Beamforming communication systems with high linearity are provided. In certain embodiments, a method of beamforming includes generating a transmit signal using a baseband processor, providing digital pre-distortion to the transmit signal, generating a radio frequency input signal based on the transmit signal using a transceiver, processing the radio frequency input signal to generate a plurality of radio frequency output signals using a plurality of transmit signal paths of a front end system, providing analog pre-distortion to at least one of the plurality of transmit signal paths using the front end system, and radiating a transmit beam in response to receiving the plurality of radio frequency output signals using an antenna array.

Abstract: Reconfigurable output baluns for wideband push-pull amplifiers are disclosed. In certain embodiments, a mobile device includes a transceiver that generates a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band, and a front-end system including a push-pull power amplifier that selectively amplifies one of the first radio frequency signal or the second radio frequency signal based on a band control signal. The push-pull power amplifier includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun. The band control signal is operable to control an impedance of the output balun.

Abstract: Techniques for power amplifier trimming based on coefficients for digital pre-distortion (DPD) are disclosed. In certain embodiments, a mobile device includes a transceiver including a first DPD circuit that digitally pre-distorts a first digital transmit signal, a second DPD circuit that digitally pre-distorts a second digital transmit signal, and a coefficient comparator circuit that generates a trimming control signal based on comparing a first plurality of coefficients of the first DPD circuit to a second plurality of coefficients of the second DPD circuit. The mobile device further includes a front end system including a first power amplifier that amplifies a first radio frequency (RF) signal from the transceiver, a second power amplifier that amplifies a second RF signal from the transceiver, and a power amplifier trimming circuit that controls trimming of at least one of the first power amplifier or the second power amplifier based on the trimming control signal.

Abstract: A surface acoustic wave resonator that has at least a first resonant frequency and a second resonant frequency is disclosed. The surface acoustic wave resonator can include an interdigital transducer electrode over a piezoelectric layer. The interdigital transducer electrode includes fingers having a first pitch. The surface acoustic wave resonator can also include a set of reflectors that is positioned over the piezoelectric layer. The set of reflectors includes a number of reflectors having a second pitch. The first pitch is greater than the second pitch. The number of reflectors is configured so as to compensate for degradation of a quality factor of the surface acoustic wave resonator due to having the first pitch greater than the second pitch.

Abstract: Power amplifiers with supply capacitor switching are provided herein. In certain embodiments, a power amplifier system includes a power amplifier that provides amplification to a radio frequency (RF) signal, a power management circuit that controls a voltage level of a supply voltage of the power amplifier, a supply capacitor having a first end connected to the supply voltage, and a bulk n-type field-effect transistor (NFET) switch. The power management circuit is operable in multiple supply control modes (for example, an average power tracking mode and an envelope tracking mode). Additionally, the bulk NFET switch is controlled based on the supply control mode of the power management circuit. The bulk NFET switch includes a ground NFET in series with a second end of the supply capacitor and a ground voltage, and a discharge NFET connected between the second end of the supply capacitor and the supply voltage.

Abstract: In some embodiments, a calibration circuit can include a first circuit configured to generate a first output voltage based on a first reference voltage, and a second circuit configured to compare the first output voltage and a second reference voltage. The calibration circuit can further include a calibration block configured to provide an adjustment to the first circuit based on the comparison of the first output voltage and the second reference voltage, with the adjustment being configured to compensate for a change in the first reference voltage. In some embodiments, such a calibration circuit can be utilized for and/or be a part of a digital-to-analog converter for wireless audio applications.