A tunable high impedance surface and its application to dual-band microstrip antenna

Abstract

This paper presents a simple method of tuning the AMC band of a high-impedance surface. The tunability is obtained with only two varactor diodes and a simple biasnetwork. The proposed structure, when used as a ground plane for a microstrip antenna, splits the resonance frequencies on the two sides of a reference antenna frequency. The resonance split is analyzed by employing cavity model and transmission line model of the patch antenna. Considerable tuning range is obtained in both the split bands. The simulated, measured and calculated results are found to be in good agreement.