CMOS silicon-on-sapphire RF tunable matching networks

Abstract

This paper describes the design and optimization of an RF tunablenetwork capable of matching highly mismatched loads to50 Ω at 1.9 GHz. Tuning was achieved using switchedcapacitors with low-loss, single-transistor switches. Simulationsshow that the performance of the matching network depends stronglyon the switch performances and on the inductor losses. A0.5 μm silicon-on-sapphire (SOS) CMOS technology waschosen for network implementation because of the relativelyhigh-quality monolithic inductors achievable in the process. Thematching network provides very good matching for inductive loads,and acceptable matching for highly capacitive loads. A 1 dB compression point greater than +15 dBm was obtained for awide range of load impedances.