Distributed coupling of dual-modes in a circular resonator and low-profiledielectric disk resonator BPF

A novel method is proposed to calculate the distributed coupling of dual-mo des in a circular resonator. New theoretical expressions are devised to acc umulate the infinitesimal coupling between orthogonal modes and their valid ity is justified by the FD-TD analysis and experiments. The distributed cou pling concept of a circular disk resonator is applied to a square disk reso nator to calculate its resonant frequency. We have fabricated two types of low-profile dual-mode square dielectric disk resonator BPF, using high diel ectric constant material (epsilon(r) = 93) having a dimension of 5 mm x 5 m m x 1 mm. The filter characteristics are explained by the transmission line circuit model.