Low-Cost Compact Inline Single-/Dual-Band Filters Based on Dual-Mode Dielectric Resonators With Highly Integrated and Flexible Mixed Couplings

This article proposes a novel approach to integrating mixed electric and magnetic couplings (MEMCs) into dual-TE₁₁-mode dielectric resonators (DRs), enabling the design of inline single- and dual-band filters with multiple transmission zeros (TZs), low manufacturing cost, and high design flexibility. The electric couplings are realized through dielectric junctions connected between DRs, while the magnetic couplings are achieved via inductive irises embedded in the enclosure walls. Both the dielectric junctions and inductive irises are seamlessly integrated into the multicoupled DRs and their enclosures, thereby eliminating the need for additional coupling components. Moreover, the introduction of dielectric junctions enables the monolithic integration of multicoupled DRs, simplifying the manufacturing and assembly processes. Based on this foundation, two MEMC configurations are proposed for single- and dual-band applications, allowing the inline construction of filters with multiple TZs. More importantly, the coupling coefficients in each configuration can be independently controlled by strategically dimensioning the irises and junctions, according to the field orthogonality of dual modes. This allows high flexibility to accommodate diverse filter specifications. For validation, several filters are designed, and two of them are fabricated and measured. The results demonstrate significant reductions in volume and cost, along with enhanced design flexibility compared to previous works.