Dielectric TM-mode resonator with improved spurious response

Modern communications systems require filters with compact resonators. Dielectric TM-mode resonators are used to shrink filter size but they usually have worse spurious response when compared to traditional metallic combline filters. Dielectric TM mode resonator with improved spurious response is presented in the article. Full 3D electromagnetic simulation results of the proposed structure are presented. The modified TM-mode resonator normalized spurious response frequency is improved from 1.17 to 1.43 when compared to classical TM-mode resonator. Experimental verification of fabricated test resonators confirms simulations.