Cree Gmbh

Björn Herrmann

Haedong Jang

Richard Wilson

Zulhazmi Mokhti

The operative bandwidth of a broadband RF amplifier is improved by using a low-pass type broadband impedance transformer, instead of a broadband matching network, in a multi-stage impedance matching network connected, e.g., to the amplifier input. The multi-stage impedance matching network comprises three stages connected in series. The first stage is a low-pass type broadband impedance transformer that provides broadband fundamental impedances and high reflection for the second harmonics. The second stage is a phase shifter that controls the location of the second harmonic reflection coefficient phases. The third stage is a high-pass input matching circuit that transforms the complex conjugate device input impedance to a real impedance. The three-stage impedance matching network provides the fundamental and harmonic frequency impedances for broadband operations, as well as controllability of the second harmonic reflection coefficient phases where the device performances are consistent across the intended bandwidth. The multi-stage impedance matching network may be connected to the input of an RF amplifier, the output, or both.

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Björn Herrmann