Provided is a 10W power amplifier for Ka band. The power amplifier includes, a drive amplifier; an intermediate stage amplifier composed of two transistors; a final stage amplifier composed of 4 transistors; a GCPW, waveguide, and a first spatial combiner unit which are sequentially connected between the drive amplifier and the intermediate stage amplifier to divide a signal output from the drive amplifier and provide the divided signal to the intermediate stage amplifier; a second spatial combiner unit, a waveguide divider, and a third spatial combiner unit which are sequentially connected between the intermediate stage amplifier and the final stage amplifier to divide signals output from the intermediate stage amplifier and provide the divided signals to the final stage amplifier; and a fourth spatial combiner unit and a waveguide combiner which are sequentially connected to the output terminal of the final stage amplifier to combine signals output from the final stage amplifier and finally output the combined signals.

A distributed amplifier includes a first transmission line for input, a second transmission line for output, an input termination resistor connecting a line end of the first transmission line and a power supply voltage, an output termination resistor connecting an input end of the second transmission line and a ground, unit cells having input terminals connected to the first transmission line and output terminals connected to the second transmission line, and a bias tee configured to supply a bias voltage to an input transistor of each of the unit cells. An emitter or source resistor of the input transistor of each of the unit cells is set to a different resistance value from each other in order for a collector or drain current flowing through the input transistor of each of the unit cells to have a uniform value.

A plurality of waveguide structures are loaded on a top surface opposed to a bottom surface of a metal case, on which a high-frequency circuit is mounted, a height, a width, and a length of each of the plurality of waveguide structures have dimensions corresponding to a quarter-wave of a cutoff frequency indicating a frequency band of a target electromagnetic wave to be blocked, and a width and a length of each of the plurality of waveguide structures have dimensions that allow only a high-frequency wave of a mode to propagate in the frequency band.

A high frequency semiconductor amplifier according to the present disclosure includes: a transistor formed on a semiconductor substrate and including a gate electrode, a source electrode, and a drain electrode; a matching circuit for input-side fundamental wave matching of the transistor; a first inductor formed on the semiconductor substrate and having one end connected to the gate electrode of the transistor and the other end connected to the matching circuit; a capacitor formed on the semiconductor substrate and having one end being short-circuited; and a second inductor formed on the semiconductor substrate and having one end connected to the gate electrode of the transistor and the other end connected to the other end of the capacitor, wherein the second inductor resonates in series with the capacitor at second harmonic frequency, has a mutual inductance of subtractive polarity with the first inductor, and the first inductor and the second inductor form mutual inductive circuits for input-side second harmonic matching.

A high frequency semiconductor amplifier according to the present disclosure includes: a transistor formed on a semiconductor substrate and including a gate electrode, a source electrode, and a drain electrode; a matching circuit for input-side fundamental wave matching of the transistor; a first inductor formed on the semiconductor substrate and having one end connected to the gate electrode of the transistor and the other end connected to the matching circuit; a capacitor formed on the semiconductor substrate and having one end being short-circuited; and a second inductor formed on the semiconductor substrate and having one end connected to the gate electrode of the transistor and the other end connected to the other end of the capacitor, wherein the second inductor resonates in series with the capacitor at second harmonic frequency, has a mutual inductance of subtractive polarity with the first inductor, and the first inductor and the second inductor form mutual inductive circuits for input-side second harmonic matching.

A power amplifier includes an amplifier circuit group including multiple amplifier circuits, a distributing circuit that distributes an input signal to each of the multiple amplifier circuits, and a combining circuit that combines output signals from the multiple amplifier circuits. Each of the multiple amplifier circuits includes an amplifier transistor including multiple cell transistors having different sizes and bias circuits that supply bias current to the respective cell transistors.

A balanced amplifier system having input and output quadrature couplers or equivalents thereof and two amplifiers there between. An RF signal is presented to a first input of an input quadrature coupler such that an amplified RF signal is output at a first output of the output quadrature coupler. A RF control signal is presented to a second input of the quadrature coupler such that an amplified control signal is outputted at the other output of the output quadrature coupler. The system is configured to reflect the amplified signal back into the second port of the output quadrature coupler in order to vary an impedance seen by the amplifiers of the balanced amplifier.

The embodiments herein relate to a power amplifier arrangement (100) comprising a main amplifier (101) comprising an output connected to a first terminal (110) of a primary winding (105) of a transformer (125). A second terminal (113) of the primary winding (105) is connected to ground (115). The power amplifier arrangement (100) comprises an auxiliary amplifier (103) comprising an output connected to a first terminal (120) of a secondary winding (108) of the transformer (125). A second terminal (118) of the secondary winding (108) is connected to a load (130).

Systems and methods are related to a distributed amplification. An amplification device can include cells including a first cell and a second cell and transmission lines including a first line and a second line. The first cell is coupled to the first line, and the second cell is coupled to the second line. The first line is configured to provide a first delay related to a delay between the first cell and the second cell. The device also includes a summer including a first input coupled to the first line and second input coupled to the second line. The summer is configured to provide an output signal.

Apparatus and methods for providing hot-switching immunity for radio frequency switching circuits are disclosed. A radio frequency switching circuit may include both a mechanical switch and a solid-state switch. The mechanical switch may be configurable to couple an output path of a power amplifier to a subsequent component in its transmission path when in a first mechanical switch state and to decouple the output path of the power amplifier from the subsequent component when in a second mechanical switch state. The solid-state switch may be configurable to operatively decouple the mechanical switch from a radio frequency power source when in a first solid-state switch state but not when in a second solid-state switch state. The solid-state switch may be in the first solid-state switch state during transitions of the mechanical switch between the first and second mechanical switch states.