Abstract: A wideband amplifier includes a first diplexer receiving broadband input signals and divides them by frequency into a low band input signal and a high band input signal. The amplifier has separate high band and low band amplifiers coupled to amplify the low and high band input signals, and a second diplexer coupled to combine outputs of the low and high band amplifiers to form a wideband output. A method of amplification of an input signal includes separating the input signal into high and low band signals, separately amplifying the high and low band signals, and combining amplified high and low band signals into an output signal.

Abstract: A method for processing waste using pyrolysis reactor include generating a microwave signal; amplifying the microwave signal into a plurality of drive signals; measuring temperature of the waste; determining, based on measured temperature, at least one phase-control signal; and outputting the at least one phase-control signal to maximize power transfer to the waste.

Abstract: A multi-level supply modulator for RF power amplifiers requires only a single independent voltage supply along with one or more flying capacitors to achieve multiple output levels. The flying capacitor is used to store the intermediate voltage level between the DC supply level and ground. A switch network is connected between the DC voltage supply and the power amplifier and is configured to provide power at variable, discrete DC voltages, for example the DC voltage supply level, ground, and a level halfway between the DC voltage supply level and ground. The flying capacitor is connected to switches in the switch network, and a sensing circuit detects the voltage across the flying capacitor and generates a feedback signal. Control circuitry controls the switch network (and thus the power supplied to the amplifier) based on the feedback signal.

Abstract: A wideband amplifier includes a first diplexer receiving broadband input signals and divides them by frequency into a low band input signal and a high band input signal. The amplifier has separate high band and low band amplifiers coupled to amplify the low and high band input signals, and a second diplexer coupled to combine outputs of the low and high band amplifiers to form a wideband output. A method of amplification of an input signal includes separating the input signal into high and low band signals, separately amplifying the high and low band signals, and combining amplified high and low band signals into an output signal.

Abstract: A microwave sensor includes a cloud of particles, e.g., Rubidium 87 atoms. A probe laser beam transitions ground-state particles in its path to an excited state. A set of one or more coupling laser beams causes excited particles to transition to a first Rydberg state so that particles in the intersection of the laser beams are in a dark superposition which is transparent to the probe laser beam so that a frequency spectrum of the probe laser beam shows a transmission peak at the laser frequency. A microwave lens focuses a microwave vector (e.g., a microwave signal) within the intersection, causing particles in the first Rydberg state to transition to a second Rydberg state, splitting the transmission peak into a pair of peaks. The intensity of the microwave vector can be calculated based on the frequency difference between the pair of peaks. The direction of the microwave vector can be determined from the location of the laser-beam intersection.

Abstract: A multi-level supply modulator for RF power amplifiers requires only a single independent voltage supply along with one or more flying capacitors to achieve multiple output levels. The flying capacitor is used to store the intermediate voltage level between the DC supply level and ground. A switch network is connected between the DC voltage supply and the power amplifier and is configured to provide power at variable, discrete DC voltages, for example the DC voltage supply level, ground, and a level halfway between the DC voltage supply level and ground. The flying capacitor is connected to switches in the switch network, and a sensing circuit detects the voltage across the flying capacitor and generates a feedback signal. Control circuitry controls the switch network (and thus the power supplied to the amplifier) based on the feedback signal.

Abstract: Biasing circuitry for RF and microwave integrated circuits keeps the quiescent current of a power amplifier integrated circuit constant when operated with a time-varying DC supply voltage. A dynamic gate bias circuit includes an on-chip sense transistor and control circuitry to keep current of the sense transistor substantially constant by varying sense transistor bias voltage to compensate for variation in the time-varying supply voltage signal. The varying bias voltage is then applied to the amplifying transistors of the power amplifier, resulting in their quiescent current being substantially independent of the time-varying supply voltage.

Abstract: Systems and methods are described for microwave-frequency, passive sensing of internal body temperature. Some implementations include one or more wearable sensors that wirelessly transmit temperature data continuously to a remote receiver. The sensor can include a probe designed to be placed on a skin site of an individual to receive near-field radiation at the skin site, and a radiometer to detect a total power of the received near-field radiation. The remote receiver includes a signal processing system that can convert the detected total power to an internal tissue temperature measurement by applying the detected power to a tissue stack model. The tissue stack model can characterize the skin site according to a set of weighting functions, each weighting function corresponding at least to electromagnetic characteristics of an associated tissue layer of the tissue stack model.

Abstract: Biasing circuitry for RF and microwave integrated circuits keeps the quiescent current of a power amplifier integrated circuit constant when operated with a time-varying DC supply voltage. A dynamic gate bias circuit includes an on-chip sense transistor and control circuitry to keep current of the sense transistor substantially constant by varying sense transistor bias voltage to compensate for variation in the time-varying supply voltage signal. The varying bias voltage is then applied to the amplifying transistors of the power amplifier, resulting in their quiescent current being substantially independent of the time-varying supply voltage.

Abstract: Systems and methods are described for microwave-frequency, passive sensing of internal body temperature. Some implementations include one or more wearable sensors that wirelessly transmit temperature data continuously to a remote receiver. The sensor can include a probe designed to be placed on a skin site of an individual to receive near-field radiation at the skin site, and a radiometer to detect a total power of the received near-field radiation. The remote receiver includes a signal processing system that can convert the detected total power to an internal tissue temperature measurement by applying the detected power to a tissue stack model. The tissue stack model can characterize the skin site according to a set of weighting functions, each weighting function corresponding at least to electromagnetic characteristics of an associated tissue layer of the tissue stack model.