Dielectric resonator elliptic-function band rejection filter with external coupling waveguide

A Ku-band elliptic-function band rejection filter (BRF) has been developed which employs a rectangular waveguide, dielectric resonators (DRs), and an external coupling waveguide to obtain attenuation poles. The high-Q DRs and the coupling waveguide realize lager attenuation with smaller number of stages than that of conventional all-pole BRFs like Chebyshev or maximally-flat response. The BRF Is designed on an equivalent circuit, which has be designed on a symmetric equivalent circuit which symmetry and thus enables simple evenand odd-mode analyses. The external waveguide is connected to the BRF through coupling slots in E-plane of main waveguide to less post-manufacture tuning might be needed compared obtain negative coupling between the DRs.