A frequency-tunable impedance matching network based on coupled inductors for RF power amplifiers

In this paper we present an RF PA employing an output impedance matching network of the pi-type, where an inductor is variable. In order to implement this tunable inductor, the coupled-inductor technique [1] is used. Although other techniques for inductor tuning exist, like those using active [2] and MEMS inductors, and p-i-n diodes [3], the coupled-inductor technique is the only providing quality factor (Q) enhancement and tunable capability.