Bandwidth-optimal single shunt-capacitor matching networks for parallel RC loads of Q ≫ 1

In this paper we demonstrate an optimized matching network that maximizes the matching bandwidth for parallel RC loads with quality factors greater than unity. The matching network includes a transmission line and a single shunt capacitor. We systematically investigate the dependance of the network´s bandwidth on the impedance and electrical length of the transmission line. Results show that high impedance lines always yield maximum bandwidth for parallel RC loads with Q > 1. A 4.3:1 MEMS varactor-based tunable matching network is measured as a vehicle to demonstrate these results. In particular, we find that up to a two-fold increase in the 10-dB reflection bandwidth is possible by utilizing high impedance lines. Wih a single 4.3:1 MEMS varactor a measured bandwidth of over 136% is obtained.