The optics of KVN antenna is a shaped Cassegrain type of which the main reflector and subreflector are shaped to have a uniform illumination pattern on an aperture plane. Because of the uniform illumination, KVN antennas can get higher aperture efficiency than value of typical Cassegrain type antenna. However, higher side-lobe level is inevitable. Following figures are OTF images of Jupiter at 22 and 43GHz, and Venus at 86 and 129GHz measured at Yonsei antenna, respectively. The map size is 12'x10' for 22 and 43GHz, and 3.5'x3' for 86 and 129GHz.
The first sidelobe pattern is clearly visible. Typical sidelobe levels of KVN antennas are 13-14dB.