Abstract: A switch mode power amplifier includes a transistor responsive to input signals above 1.0 GHz and which includes one terminal coupled to ground and another terminal conductively coupled to a power source. A resonant circuit coupled the second terminal to an output with a resistive load coupled across the output and ground. When the transistor is turned on the second terminal is coupled to ground and when the transistor is turned off, current from the power supply to the second terminal is steered into internal capacitance of the transistor and causes voltage on the second terminal to rise to a maximum value and then decrease, the voltage at the second terminal being coupled to the output terminal through the resonant circuit. In preferred embodiments, the transistor comprises a compound semiconductor field effect transistor with the first terminal being a source terminal and the second terminal being a drain terminal.

Abstract: High power, high frequency switches include a transmission line having at least three portions that are serially coupled between an input port and an output port to define at least two nodes and to carry a high power, high frequency signal between the input port and the output port. First and second power transistors are provided. At least a third power transistor also is provided. The controlling electrode(s) (gate) of the first, second and/or third power transistor(s) are responsive to a switch control input. The controlled electrodes (source/drain) of a respective one of the first and second power transistors, and of a respective one of the third power transistor(s) are serially coupled between a respective one of the at least two nodes and a reference voltage. The power transistors may be silicon carbide MESFETs.

Abstract: A high power Doherty RF amplifier utilizes multi-stage amplifier modules for both the main amplifier and the peak amplifiers. In one embodiment of a two way two stage amplifier, the first stage of each amplifier module can include signal pre-distortion whereby the first stage compensates for distortion in both the first and second stages. The design is simple and results in a high efficiency amplifier with high gain. In one embodiment, a commercially available CREE PFM1903OSM power module is used in both the main amplifier and the peak amplifier.

Abstract: A switch mode power amplifier includes a transistor responsive to input signals above 1.0 GHz and which includes one terminal coupled to ground and another terminal conductively coupled to a power source. A resonant circuit coupled the second terminal to an output with a resistive load coupled across the output and ground. When the transistor is turned on the second terminal is coupled to ground and when the transistor is turned off, current from the power supply to the second terminal is steered into internal capacitance of the transistor and causes voltage on the second terminal to rise to a maximum value and then decrease, the voltage at the second terminal being coupled to the output terminal through the resonant circuit. In preferred embodiments, the transistor comprises a compound semiconductor field effect transistor with the first terminal being a source terminal and the second terminal being a drain terminal.