High Performance Dual-Band Filter With Flexible Frequency Allocation Using Hybrid Boundary Dual-Mode Dielectric Resonator

In this paper, a dual-band filter with flexible frequency allocation is proposed using novel dual-mode T-shaped dielectric resonator (DR). Benefiting from the hybrid electromagnetic boundary and triangular chamfers on DRs, dual-mode frequencies could be manipulated independently while keeping wide spurious-free window. Then not only tiny but also large frequency ratios could be both achieved via the presented structure. Moreover, mechanisms of independent adjustments on external and internal couplings are investigated, facilitating flexible dual-band bandwidth control. For verification, a three-order dual-band filter operating at 1.8 and 2.1 GHz is designed. The exhibited low loss and high selectivity within compact size illustrate the proposed filter at high-standard multiband communication systems.