Tuneable Electromagnetic Bandgap Structures Based on Ba0.25Sr0.75Ti03 Parallel-Plate Varactors on Silicon Coplanar Waveguides

Abstract

Experimental performance of Electromagnetic Band Gap (EBG) structures, based on Coplanar Waveguides (CPW) periodically loaded by high-Q-factor ferroelectric varactors is reported. The varactors are made of Ba0.25Sr0.75Ti03 films grown by laser ablation on thick Pt/Au/Pt electrodes. Due to the thick bottom electrodes the varactors have Q-factor larger than 40 at 45 GHz, which is higher in comparison with semiconductor varactors. Up to 30% tuning of the pass band edge is achieved at ¿20 dB level under 25V DC bias.