ANALYSIS AND DESIGN OF QUADRUPLE-RIDGED WAVE-GUIDES

In a previous paper, a unified approach has been proposed for the analysis and design of single- and double-ridged waveguides by a magnetic field integral equation (MFIE) formulation [1], This paper presents a continuing work with emphasis on the design of quadruple-ridged waveguides,The characteristics of square, circular and diagonal quadruple-ridged waveguides, including cutoff frequencies, attenuation, impedance and modal field distributions, are first time systematically analyzed and reported, Distinct to being in a single- or double-ridged waveguide, the fundamental-mode in a quadruple-ridged waveguide has a cutoff frequency very close to that of the second-lowest mode, thus the natural single mode bandwidth is very small, However, when the second-lowest mode is effectively suppressed or not excited, a very wide bandwidth (6:1) can be achieved, This unique property, plus the capabilities of dual-polarization, high power, and low impedance, makes the quadruple-ridged waveguides well-suited to many antenna and microwave applications.