RF-MEMS variable matching networks and switches for multi-band and multi-mode GaN power amplifiers

摘要

This work presents radio-frequency-microelectromechanical-system (RF-MEMS)-based tunable matching networks for a multi-band gallium nitride (GaN) power amplifer (PA) application. In the frequency range from 3.5-8.5 GHz return losses of 5-10 dB were measured for the input network, matching impedances close to the border of the Smith chart. For the output matching network return losses of 10-20 dB and insertion losses of 1.3-2 dB were measured. The matching networks can tune the PA to four different operating frequencies, as well as changing the transistor's mode of operation from maximum delivered-output-power to maximum power-added-efficiency (PAE), while keeping the operating frequency constant. Furthermore, different single pole double throw (SPDT)-switches are designed and characterized, to be used in frequency-agile transmit/receive-modules (T/R modules).