Novel waveguide pseudo-elliptic filters using slant ridge resonators

This paper presents a novel resonant structure for the design of compact pseudo-elliptic filters in waveguide technology. The resonator consists of a rectangular ridge which is arbitrarily located and oriented within a rectangular waveguide. Under certain conditions, by exciting the ridge with the fundamental TE10 mode of the waveguide, the resonator exhibits a transmission zero besides the transmission pole, thus behaving as a singlet. This element can be used as a basic building block for the design of higher order filters. In this work an in-line 5th order filter with three transmission zeros has been fabricated and tested, demonstrating the feasibility of the proposed design.