Balanced Feed Low Cross-Polarization Quad-Ridged Horn Antenna with Center Cross Fusiform Loaded

This communication presents a novel quad-ridged horn (QRH) antenna incorporating a balanced feed. A cross-shaped fusiform structure is mounted in the center of the QRH. The fusiform structure has the effect of suppressing the cross-polarization component by improving the conventional QRH $TE_{11}$ mode. The communication presents an equivalent circuit that has been derived for the proposed balanced feed network. Four SMA probes are symmetrically distributed around the horn wall and the inner conductors of the two probes facing each other are connected. The cross-polar level, within a 30° solid angle, is less than -23 dB from 2 to 6 GHz. The measured isolation between two orthogonal linearly polarized ports is higher than 42 dB and the return loss is lower than -15 dB over the entire working frequency band.