Two-Material and Ridged Metal-Strip Substrate Integrated E-Plane Waveguide for Wideband Applications

This paper presents a novel substrate integrated E-plane waveguide (SIEW) with an extended single-mode bandwidth for broadband E-plane devices. The proposed structure consists of four dielectric layers, whose middle layer adopts a material with a high permittivity, and the remaining layers utilize the low-permittivity material. The middle layers are partially plated with a pair of ridged copper strips to guide the longitudinal current, where the strips aligning the direction of electroplating through holes assist in the propagation of E-plane electromagnetic waves for the bandwidth extension. The proposed SIEW achieves the cutoff frequencies of 5.8 and 29.2 GHz at the fundamental and second modes, respectively, resulting in a cutoff frequency ratio (CFR) of approximately 5.0. Consequently, the SIEW is fabricated and tested to verify its electromagnetic properties.