Research prototype of a multi-aperture coupler for mode diversity

A multiaperture mode-diversity coupler built to operate in the A-band (26.5-40.0 GHz) is described. It can separate the horizontally polarized higher-order mode from the feed waveguide of a horn reflector antenna. This type of coupler can be used to provide diversity protection to microwave radio links. Measurements show that this coupler adequately separates the higher-order horizontal mode and does not affect propagation of the vertical polarized signals; therefore, it can be used in links where both polarizations are employed. This coupler can be retrofitted to existing horn antennas. Unlike other pattern diversity schemes it does not degrade the sidelobe performance.<
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