A compact dual-mode microstrip filter using hexagonal resonator and capacitive loading technique

In this paper, a dual-mode filter using novel hexagonal resonator with capacitive loading are introduced, fabricated and verified by measurement. The structures discussed here is of simple design procedure and easy fabrication. Compare with conventional dual-mode hexagonal filters, the proposed one shows a compact size of 0.3 lambda_gtimes32 lambda_g, low insertion loss of 0.5-dB, higher power handling capability and moreover, the capacitive loading structure improves the filter´s selectivity and upper band suppression than their closed loop counterparts. It is highly suitable for high temperature superconductor(HTS) devices, micro- and millimeter wave front-ends and wireless communication applications.