A novel microwave ferroelectric varactor with hybrid coplanar and parallel plate structure

Abstract

A novel microwave ferroelectric varactor with hybrid coplanar and parallel plate structure is presented. The tunability of conventional coplanar varactors is demonstrated to be highly improved by applying a dc bias through high resistance parallel plate electrodes. The requirements for stringent lithography were much less compared with the conventional parallel plate structure and easily provided a suitable capacitance for circuit impedance matching. The quality factor (Q factor) of the hybrid varactor increased as the frequency increased, which suggests that the proposed new hybrid structure is a potential alternative method in the development of high frequency microwave ferroelectric tunable devices. The method of applying a dc bias using high resistance electrodes may provide a simplified procedure in complex agile microwave devices. © 2009 IOP Publishing Ltd.