Abstract: Exemplary techniques for implementing an amplifier suitable for RF amplification, such as a tuned class DE amplifier, are disclosed. One disclosed embodiment of a circuit for amplifying an RF signal includes a push-pull amplifier comprising a push transistor and a pull transistor. A first driver amplifier drives the push transistor of the push-pull amplifier with a first RF signal. A second driver amplifier drives the pull transistor of the push-pull amplifier with a second RF signal different from the first RF signal.

Abstract: Impedance matching techniques can be used to match an amplifier to an antenna for signal transmission. Some impedance matching techniques use an integrated passive component and an integrated transformer. Some impedance matching techniques include the use of an integrated n:m transformer, where n?m. Several n:m transformer implementations are described.

Abstract: Impedance matching techniques can be used to match an amplifier to an antenna for signal transmission. Some impedance matching techniques use an integrated passive component and an integrated transformer. Some impedance matching techniques include the use of an integrated n:m transformer, where n?m. Several n:m transformer implementations are described.

Abstract: Exemplary techniques for implementing an amplifier suitable for RF amplification, such as a tuned class DE amplifier, are disclosed. One disclosed embodiment of a circuit for amplifying an RF signal includes a push-pull amplifier comprising a push transistor and a pull transistor. A first driver amplifier drives the push transistor of the push-pull amplifier with a first RF signal. A second driver amplifier drives the pull transistor of the push-pull amplifier with a second RF signal different from the first RF signal.

Abstract: An amplifier stage capable of delivering a peak limited voltage pulse with sharp transitions, at a desired width and duty cycle, and with high efficiency is disclosed. One disclosed embodiment relates to a circuit that includes a tuned class D amplifier that receives an input signal and generates a pulsed RF output signal in response to the input signal. The pulsed RF output signal has a greater power than that of the input signal.

Abstract: Systems and methods for switching electronic signals are disclosed. The switching may be performed with a low loss and low peak voltages. The switching scheme is suitable for switching RF signals, for example, and may be used in devices such as wireless systems, terminals, and handsets. One exemplary embodiment is directed to a CMOS-implemented transmit/receive switching system. The system comprises one or more transmit ports, each coupled via a respective transmit path to an input/output port and one or more receive ports, each coupled via a respective receive path to the input/output port. Each receive path comprises a switching circuit comprising a transistor and an inductor in parallel with the transistor. The switching circuit is adapted to at least substantially isolate the respective receive port from the input/output port when the transistor is in an on state and operatively couple the respective receive port to the input/output port when the transistor is an off state.

Abstract: Exemplary techniques for implementing an amplifier suitable for RF amplification, such as a tuned class DE amplifier, are disclosed. One disclosed embodiment of a circuit for amplifying an RF signal includes a push-pull amplifier comprising a push transistor and a pull transistor. A first driver amplifier drives the push transistor of the push-pull amplifier with a first RF signal. A second driver amplifier drives the pull transistor of the push-pull amplifier with a second RF signal different from the first RF signal.

Abstract: An amplifier stage capable of delivering a peak limited voltage pulse with sharp transitions, at a desired width and duty cycle, and with high efficiency is disclosed. One disclosed embodiment relates to a circuit that includes a tuned class D amplifier that receives an input signal and generates a pulsed RF output signal in response to the input signal. The pulsed RF output signal has a greater power than that of the input signal.

Abstract: Described is a closed-loop power detector/controller for wireless systems employing a non-constant amplitude envelope modulation scheme. Any AM component in the feedback signal resulting from non-constant amplitude envelope signals is eliminated via feed-forward cancellation of the envelope signal. Generally, a signal representative of the AM variation in the non-constant amplitude envelope signals prior to amplification is obtained. This AM variation signal is then used to cancel any AM component in the feedback signal resulting from the non-constant envelope to create a power amplifier control signal without any AM variation, only the desired ramp profile.

Abstract: A high performance single-pole-double-throw (SPDT) Transmitter/Receiver (T/R) FET switch utilizes a plurality of multi-gate FETs in series to realize low insertion loss, low harmonic distortion and high power handling capabilities. The SPDT switch consists of an antenna port, a transmitter branch coupled to a transmitter port through a plurality of multi-gate FETs in series and a receiver branch coupled to a receiver port through a plurality of multi-gate FETs in series. When a high power signal passes from the transmitter port to the antenna port through the transmitter branch, the receiver branch is required to be shut off electrically to prevent the high power signal from leaking to receiver port. This leakage can degrade the isolation of the switch and cause harmonic distortion. Furthermore, the transmitter branch is required to provide a resistance as small as possible to reduce the power loss when it passes through the transmitter branch to the antenna port.

Abstract: A SPDT switch includes an antenna port. A transmitter section is coupled to a transmitter port. The transmitter section includes a plurality of transistors that are coupled in series relative to each other. A receiver section is coupled to a receiver port. The receiver section includes a plurality of transistors that are coupled in series relative to each other, so that when the transmitter section transmits high power to the antenna port, the receive section is effectively off to provide isolation to the receive port. The receiver port is coupled to the receiver section using at least one external capacitor. The at least one external capacitor is used to improve the power handling capability and harmonic performance of the switch.

Abstract: A coupler circuit for sampling an output power of a signal from an output power source has at least one first sampling element for sampling a first portion of the signal and at least one second sampling element for sampling a second portion of the signal. The first sampling element and the second sampling element are separated by an output matching network defined by a set of S-parameters. A processor coupled to the at least one first and second sampling elements determines the output power based on at least the first portion of the signal and the second portion of the signal. A detector may be coupled to the processor to measure whether the first and second portion of the signal or the output power determined by the processor.

Abstract: A power amplifier module includes an input for receiving a signal having an input power level, at least one power amplifier coupled to the input to increase the input power level of the signal to an output power level and a power calibration and control module coupled to the power amplifier for measuring the output power level and correcting the output power level measurement based on a set of factors. The power calibration and control module further controls the at least one power amplifier to produce an output power level equivalent to a target power level. The power calibration and control module may include a power detector, a power calibrator and a power controller. The power amplifier module may further include a power set interface coupled to the power calibration and control module for providing the target power level.

Abstract: Described is a closed-loop power detector/controller for wireless systems employing a non-constant amplitude envelope modulation scheme. Any AM component in the feedback signal resulting from non-constant amplitude envelope signals is eliminated via feed-forward cancellation of the envelope signal. Generally, a signal representative of the AM variation in the non-constant amplitude envelope signals prior to amplification is obtained. This AM variation signal is then used to cancel any AM component in the feedback signal resulting from the non-constant envelope to create a power amplifier control signal without any AM variation, only the desired ramp profile.

Abstract: A coupler circuit for sampling an output power of a signal from an output power source has at least one first sampling element for sampling a first portion of the signal and at least one second sampling element for sampling a second portion of the signal. The first sampling element and the second sampling element are separated by an output matching network defined by a set of S-parameters. A processor coupled to the at least one first and second sampling elements determines the output power based on at least the first portion of the signal and the second portion of the signal. A detector may be coupled to the processor to measure whether the first and second portion of the signal or the output power determined by the processor.

Abstract: A power amplifier module includes an input for receiving a signal having an input power level, at least one power amplifier coupled to the input to increase the input power level of the signal to an output power level and a power calibration and control module coupled to the power amplifier for measuring the output power level and correcting the output power level measurement based on a set of factors. The power calibration and control module further controls the at least one power amplifier to produce an output power level equivalent to a target power level. The power calibration and control module may include a power detector, a power calibrator and a power controller. The power amplifier module may further include a power set interface coupled to the power calibration and control module for providing the target power level.

Abstract: A Doherty-type power amplifier suitable for satellite telecommunication systems provides linear amplification of noise-like RF signals that have multiple carriers spread over a large instantaneous bandwidth. Efficiencies of 40% to 50% are achieved using PHEMT devices. The power amplifier includes a carrier amplifier that operates a low power levels and a peak amplifier that operates at high power levels. For low power levels, the carrier amplifier delivers its output into twice the optimum load resulting in high efficiency, while the peak amplifier is turned off. At high power levels, both the carrier and the peak amplifier is working into an optimum load and maximum power is delivered. Output matching sections are used to transform the very low optimum load impedance of the PHEMT devices prior to phase shifting and combining.

Abstract: An improved Doherty amplifier for operation at microwave frequencies using microstrip circuit technology and gallium arsenide devices to achieve greater efficiency and linearity. The circuit divides the input power equally between a carrier amplifier and peak amplifier with a quarter-wave delay at the input to the peak amplifier insuring that the output power of the two amplifiers will be in phase at the load. A three-port network combines the phase-delayed carrier amplifier output with the output of the peak amplifier. The outputs of the two amplifiers are connected together by a quarter wave transmission line of impedance R. A load of one-half the optimum load (R/2) is attached to the output of the peak amplifier. A quarter-wave line section provides the transition from R/2 to the desired impedance, R. When the peak amplifier is off, its output impedance is infinite and the output power of the carrier amplifier is delivered entirely to the load.