Dual-Band Dielectric Resonator Filters Employing TE_01δ Mode and Degenerate HEH₁₁ Modes

Abstract

This article presents a novel dual-band bandpass filter based on cylinder dielectric resonators, where the dielectric mode TE01δ is exploited to generate the first passband, and the two degenerate modes HEH11 are used to generate the second passband. In order to achieve the needed couplings between the input/output port and the TE01δ/HEH11 modes, a probe with both a straight and a curved section is designed. The needed inner couplings between modes of contiguous cavities are instead obtained by using inductive irises and capacitive probes. A systematic design procedure is provided for achieving the center frequencies and bandwidths with large design freedoms. To validate the methods, a dual-band filter working at 2.249 GHz and 2.607 GHz with bandwidths of 32 MHz, is designed and fabricated. The Filter shows low insertion loss, high rejection and compact dimensions. Measured results demonstrate the feasibility of the proposed approach.

Keywords

• Dual-band bandpass filter
• dielectric resonator
• dual-mode
• low insertion loss