A High-Isolation Wide-Beam Compact Range Transceiver Feed Based on the Radiation Null of a Horn-Shaped Absorber

This letter presents a method to improve the isolation of wide-beam compact range transceiver feeds. First, by analyzing the multimode coupling strength of different transceiver feed position layouts and polarization directions, an angle placement principle for dual-polarized transceiver feeds is proposed. Then, it is proposed to introduce a horn-shaped absorber at the feed aperture. The radiation null in the horizontal direction is achieved through the phase relationship between the dielectric surface waves and free-space waves, which solves the problem of the slow sidelobe roll-off of wide-beam feeds. Finally, a feed prototype with an absorber is fabricated and measured. The results show that across the entire K band, the transceiver isolation is improved by an average of 17.4