MULTIPLE APERTURE HIGHER-ORDER MODE COUPLERS - ANALYSIS AND DESIGN

A special class of multiple aperture couplers is used in terrestrial m icrowave radio to provide mode diversity protection to mitigate effect s of multipath fading. In these couplers, one of the waveguides is ove rmoded and specific modes are extracted from this waveguide to a small er waveguide through a set of circular apertures without affecting oth er propagating modes, A comprehensive analytical method applicable to both horizontal and vertical multi-aperture couplers is presented. The analysis, design and measured results for a horizontal mode coupler a re discussed.