Load modulation for high power applications based on printed ceramics

This paper addresses the design and measurement of a low cost tunable impedance matching network (TMN) employing Barium-Strontium-Titanate (BST) for high frequency and high power applications. Based on requirements of a class AB mode high power amplifier, a pi-topology circuit was designed, photo-lithographically processed and measured. The work demonstrates a tunable matching network, transforming low impedance Z
i
=(4‥13)-(3.5‥13)j Ohm to a fixed 50 Ohm load, exhibiting insertion losses of not more than 0.9dB at 2.0 GHz. For initial testing, a tunable PA was designed by implementing the TMN at its output. First system measurements show an output power of 40.5dBm with a drain efficiency of 58% at 2.0 GHz.