Abstract: Radio frequency (RF) communication systems with interference cancellation for coexistence are provided herein. In certain embodiments, an RF communication system includes a transmitter including a power amplifier that amplifies an RF transmit signal to generate an amplified RF transmit signal, a receiver including a low noise amplifier (LNA) that amplifies an RF receive signal, and an interference cancellation circuit. The interference cancellation circuit includes a filter that generates an analog interference cancellation signal based on filtering the amplified radio frequency transmit signal, a controllable phase circuit that provides a phase adjustment to the analog interference cancellation signal, and a controllable gain circuit that provides a gain adjustment to the analog interference cancellation signal. The interference cancellation circuit injects the analog interference cancellation signal into the LNA to compensate the receiver for interference arising from the transmitter.

Abstract: RF communication systems with interference cancellation for coexistence are provided herein. In certain embodiments, an RF communication system includes a transmitter that transmits a transmit signal through a first front end circuit, a receiver that processes a receive signal from a second front end circuit, and a feedback receiver that processes a feedback signal from the first front end circuit to generate a digital interference cancellation signal that compensates the receiver for interference arising from the transmitter.

Abstract: Radio frequency (RF) communication systems with coexistence management are provided herein. In certain embodiments, a method of coexistence management in a mobile device includes providing an RF receive signal from a first front end system to a first transceiver, generating an RF transmit signal and an RF observation signal using a second front end system, the RF observation signal generated based on observing the RF transmit signal, generating digital observation data based on the RF observation signal using a second transceiver, downconverting the RF receive signal to generate a baseband receive signal using the first transceiver, and compensating the baseband receive signal for RF signal leakage based on the digital observation data using the first transceiver.

Abstract: Radio frequency (RF) communication systems with coexistence management are provided herein. In certain embodiments, a method of coexistence management includes generating an RF observation signal based on observing a cellular transmit signal using a cellular front end system, processing the RF observation signal to generate digital observation data using a cellular transceiver, generating a digital wireless local area network receive signal based on processing an RF wireless local area network receive signal using a wireless local area network transceiver, processing the digital observation data to determine an estimated amount of aggressor spectral regrowth present in the RF wireless local area network receive signal using a spectral regrowth modeling circuit of the wireless local area network transceiver, and compensating the digital baseband wireless local area network receive signal for RF signal leakage based on the estimated amount of aggressor spectral regrowth.

Abstract: Radio frequency (RF) communication systems with coexistence management are provided herein. In certain embodiments, a method of coexistence management in a mobile device includes processing an RF receive signal to generate a digital baseband receive signal using a receive channel of a first transceiver, processing a first RF observation signal to generate a first digital observation signal using a first observation channel of the first transceiver, generating spectral regrowth observation data based on processing process the first digital observation signal using a first spectral regrowth baseband sampling circuit of the first transceiver, and compensating the digital baseband receive signal for RF signal leakage based on the spectral regrowth observation data and on direct transmit leakage observation data using a discrete time cancellation circuit of the first transceiver.

Abstract: Reconfigurable antenna systems integrated with a metal case are provided herein. In certain embodiments, user equipment (UE) for a cellular network includes a metal case and an antenna system for transmitting and/or receiving wireless signals. The antenna system includes a tuning conductor formed in the metal case, a patch antenna element that is spaced apart from the tuning conductor, and a switch electrically connected in series between the tuning conductor and a ground voltage. The switch electrically connects the tuning conductor to the ground voltage in an on state and electrically disconnects the tuning conductor from the ground voltage in an off state.

Abstract: According to some implementations, a radio-frequency (RF) device includes a communication interface coupled to a serial bus. The RF device also includes a monitoring component coupled to the communication interface, the monitoring component configured to monitor the serial bus for first data transmitted to a first device coupled to the serial bus and configure the RF device based on the first data.

Abstract: Apparatus and methods for bias switching of power amplifiers are provided herein. In certain configurations, a power amplifier system includes a power amplifier that provides amplification to a radio frequency (RF) signal and a bias control circuit that biases the power amplifier. The power amplifier includes an amplification transistor that receives the RF signal at an input, and a first bias network and a second bias network each connected to the input. The bias control circuit includes a first switch, a first reference current source that provides the first reference current to the first bias network through the first switch, a second switch, and a second reference current source that provides the second reference current to the second bias network through the second switch.

Abstract: In one aspect, an apparatus includes: a fast Fourier transform (FFT) engine to receive and convert a plurality of orthogonal frequency division multiplexing (OFDM) samples into a plurality of frequency carriers; a detector coupled to the FFT engine to determine a channel estimate for a first frequency carrier using a first channel estimate for the first frequency carrier and a plurality of other channel estimates, each of the plurality of other channel estimates for one of a plurality of neighboring frequency carriers within an evaluation window, and determine a log likelihood ratio (LLR) for the first frequency carrier using the channel estimate for the first frequency carrier; and a decoder coupled to the detector to decode a first OFDM symbol comprising the first frequency carrier using the LLR for the first frequency carrier.

Abstract: Envelope tracking systems for power amplifiers are provided herein. In certain embodiments, an envelope tracker system includes a first power amplifier that amplifies a first radio frequency (RF) signal and receives power from a first supply voltage, a second power amplifier that amplifies a second RF signal and receives power from a second supply voltage, and an envelope tracker including a first modulator that generates a first output current based on an envelope of the first RF signal and a plurality of regulated voltages, a second modulator that generates a second output current based on an envelope of the second RF signal and the regulated voltages, a first combiner that combines a first DC voltage with the first output current to generate the first supply voltage, and a second combiner that combines a second DC voltage with the second output current to generate the second supply voltage.

Abstract: A shield enclosure includes a housing with a peripheral wall that defines a cavity, and a cover removably coupleable to the housing to at least partially seal the cavity. The cavity is sized to receive a printed circuit board therein. The housing shields the printed circuit board from electromagnetic interference and noise during noise figure testing of a radiofrequency component on the printed circuit board.

Abstract: Fuse programming circuits, devices and methods. In some embodiments, a fuse circuit can include a fuse pad configured to receive a voltage, a fuse having a first end coupled to the fuse pad and a second end coupled to a switching element configured to enable a current to pass from the fuse pad to a ground potential.

Abstract: A delay measurement circuit includes a first skew circuit disposed proximate to a first bonding pad configured to receive a first clock signal having a first frequency. The delay measurement circuit includes a second skew circuit disposed proximate to a second bonding pad configured to receive a second clock signal having a second frequency. The first and second skew circuits each have a first mode of operation as zero-delay-return path and a second mode of operation as a synchronized pass path. The delay measurement circuit includes a pair of conductive traces coupled to the first skew circuit, another pair of conductive traces coupled to the second skew circuit, a time-to-digital converter circuit, and a switch circuit configured to selectively couple the time-to-digital converter circuit to the first skew circuit via the pair of conductive traces and the second skew circuit via the other pair of conductive traces.

Abstract: Aspects of this disclosure relate to a radio frequency system with tunable notch filtering. The radio frequency system includes a first tunable filter and a second tunable filter. The first tunable filter is coupled between an output of a power amplifier and a radio frequency switch. The second tunable filter includes mutually coupled inductors and a tunable impedance circuit electrically connected to at least one of the mutually coupled inductors. The second tunable filter is coupled between an antenna switch and an antenna node. Related methods and wireless communication devices are also disclosed.

Abstract: A surface acoustic wave (SAW) resonator comprises a plurality of interdigital transducer (IDT) electrodes disposed on a multilayer piezoelectric substrate including a layer of piezoelectric material having a lower surface bonded to an upper surface of a layer of a dielectric material. The dielectric material has a lower surface bonded to an upper surface of a carrier substrate. The plurality of IDT electrodes include an upper layer and a lower layer. The upper layer is formed of a material having a higher conductivity than the lower layer. The lower layer is formed of a material having a higher density than the upper layer to provide for reduction in size of the SAW resonator.

Abstract: A piezoelectric microelectromechanical system microphone comprises a piezoelectric element configured to deform and generate an electrical potential responsive to impingement of sound waves on the piezoelectric element, a sensing electrode disposed on the piezoelectric element and configured to sense the electrical potential, and a dummy electrode electrically unconnected to the sensing electrode and disposed on a portion of the piezoelectric element that is free of the sensing electrode, the dummy electrode configured to reduce static deformation of the piezoelectric element caused by residual stresses in the piezoelectric element.

Abstract: Circuits with filters and acoustic resonators. In some embodiments, a radio-frequency circuit can include a plurality of nodes and a common node. The radio-frequency circuit can further include a signal path implemented between each of the plurality of nodes and the common node. Each corresponding signal path can include a filter having a first Q-factor value and a respective resonator having a second Q-factor value higher than the first Q-factor value.

Abstract: A switching circuit comprises a first filter, a second filter and a plurality of switches. The first filter is configured to filter a first frequency band, a second frequency band that is adjacent to the first frequency band and a gap band between the first frequency band and the second frequency band. The second filter is configured to filter the second frequency band. The plurality of switches is configured to route signals from an antenna through one of the first filter and second filter.

Abstract: Disclosed herein are embodiments of low temperature co-fireable dielectric materials which can be used in conjunction with high dielectric materials to form composite structures, in particular for isolators and circulators for radiofrequency components. Embodiments of the low temperature co-fireable dielectric materials can be scheelite or garnet structures, for example barium tungstate. Adhesives and/or glue is not necessary for the formation of the isolators and circulators.

Abstract: A time error vector is determined using pairs of two closest points of input-referred noise data that straddle respective crossing times indicating when a clock signal representation crosses a threshold value, a slew rate of the clock signal representation, and the crossing times. A system filter is applied to the time error vector in the frequency domain. A first RMS value is determined indicating a jitter value present in the filtered time error vector. A raw clock signal time error vector of the clock signal under test is generated, the system filter is applied to the raw clock signal time error vector in the frequency domain, and a second RMS value indicating a jitter content of the filtered raw clock signal time error vector is determined. The second RMS value is corrected using the first RMS value to thereby generate a jitter measurement compensated for input-referred noise.