Inline pseudoelliptic waveguide filters using asymmetric Iris coupled transverse rectangular ridge resonators

Abstract

AbstractIn this work, a new structure for the implementation of inline pseudoelliptic waveguide filters using non-resonating modes, based on asymmetric iris coupled transverse rectangular ridge resonators has been proposed. The basic structure is comprised of a ridge that is always centered and transverse to the waveguide center axis and has the ability to create a transmission zero (TZ) above or below the passband without involving any rotation of the ridge, thus enabling quicker design of the resulting filters by allowing the use of more efficient analysis tools like FEST3D, in addition to the more general purpose methods like HFSS. A centered ridge enables the ease of manufacturing through machining. The proposed structure makes use of rectangular waveguide's dominant TE10 mode as a non-resonating mode to create an alternate energy path from source to load, thus realizing a TZ, while the asymmetric irises excite the ridge resonator, enabling the overall structure to act as a singlet capable of producing both a pole and a TZ. A third-order filter with one TZ and a fifth-order filter with two TZs have been designed and manufactured. Measured results show good consistency with the simulated data, validating the viability of the proposed structure.