An 81% Bandwidth Parallel-Plate Horn Array Using a Single-to-Double Ridge Waveguide Vertical Interconnection

A novel ultra-wideband parallel-plate (PP) horn array with an air-filled single-ridge waveguide (SRW) feed network is presented. By designing a wideband double 90°-bend single-to-double (STD) ridge waveguide transition as vertical interconnections between the major full-corporate feed network and feed cavities for 2 × 2 subarrays, a significantly improved bandwidth of above 80% is obtained by the proposed feed network. A PP horn radiator with a widened bandwidth of 84% is also designed by increasing the height of broad walls of the horn. By combining the feed network with the horn radiator, an 8 × 8 array is developed. A prototype by using layered milling technology experimentally verifies an ultra-wide bandwidth of 81% (17.2–40.6 GHz), a peak gain of 28.9 dBi, and stable unidirectional radiation patterns. Benefitting from excellent performance, the presented array is attractive for emerging millimeter-wave multiband applications.