This work presents radio-frequency-microelectromechanical-system (RF-MEMS)-based tunable input- and output-matching networks for a multi-band gallium nitride (GaN) power-amplifier applications. In the first part, circuit designs are shown and characterized for a fixed operation mode of the transistor, i.e. either a maximum-output-power- or a maximum-power-added-efficiency (PAE)-mode, which are finally combined into a multi-mode-matching network (M3N); the M3N allows to tune the operation mode of the transistor independently of its operational frequency. The matching networks are designed to provide optimum matching for the power amplifier at three to six different operating frequencies for maximum-output-power- and maximum-PAE-mode. In the frequency range from 3.5 to 8.5 GHz, return losses of 10 dB and higher were measured and insertion losses of 0.5–1.9 dB were demonstrated for the output-matching networks. Further characterizations were performed to test the dependency on the RF-input power, and no changes were observed up to power levels of 34 dBm when cold-switched.
A compact multi-mode multi-band power amplifier with harmonic-suppression matching networks for GSM/TD-SCDMA/LTE terminals