Substrate Integrated E-Plane Waveguide (SIEW) to Design E-Plane and Dual Polarized Devices

Substrate-integrated waveguide (SIW) uses rows of plated through holes to emulate the intact vertical walls of a waveguide circuit. It succeeds in the design of H-plane circuits but not the E-plane circuits because an E-plane circuit requires longitudinal current on the vertical walls that is not supported by SIW. In this paper, a novel substrate-integrated E-plane waveguide (SIEW) is presented. In SIEW, additional copper strips are inserted at the middle layer of the structure while the copper plated through holes remain unchanged. Consequently, the vertical current flows on the through holes and the longitudinal current flows along the middle strips to meet the wave propagation requirement in the E-plane waveguide circuit. The insertion loss, cutoff frequency, and propagation constant of the SIEW are investigated. As examples, an empty SIEW, a bandpass septum SIEW filter, and a dual-polarized SIEW horn antenna are designed using the SIEW technique. All of them are constructed and their performance is measured to validate the design.