A low sidelobe earth station antenna for the 4/6 GHz band

A full-scale, 7.6 meter satellite earth station antenna employing offset geometry and absorbing shields has been built and tested. The peak sidelobe envelope in the critical 6 GHz transmit band is 10-15 dB lower than present FCC/Intelsat requirements over the full range of aspect angles. First sidelobes are approximately -30 dB in the receive band and -35 to -40 dB in the transmit band. Worst case off-axis cross-polarized peaks are more than 30 dB below the co-polarized peak in both bands. The penalty in aperture efficiency to achieve this performance is only about 0.75 dB when compared with the most efficient conventional antennas. Dual-polarized feed ports, transmitters, and receivers are all located at ground level within a short distance of each other for all antenna pointing angles.