High efficiency antenna array with optimized corporate hybrid feed

A low-cost Ku-band array of circularly polarized microstrip antennas benefiting from a low-loss waveguide feed network is demonstrated (patent pending). The 128 elements of the array which are arranged in a 4-by-32 configuration are subdivided into four 4-by-8 subarrays. To maintain feed losses and thus the overall noise temperature at a minimum, the subarrays are excited using a 1-by-4 corporate feed network of hollow metallic waveguides. Due to a low-loss foam substrate, the array elements show high circular polarization gain of 7.5 dBic and wide relative bandwidth of 4%. The measured circular polarization gain of the array amounts to 25.6 dBic with an aperture efficiency of 51% in the Ku-band of frequencies