Simultaneous Multifrequency Near-Field Radio Holography of Reflector Antennas

We propose a simultaneous multifrequency near-field radio holography method for measuring reflector surfaces of radio telescopes with high precision. With a comb spectrum generator as the beacon source, this method can obtain aperture phase maps at multiple frequencies simultaneously and thereby reduce the interference of multipath signals and improve the measurement precision of radio holography. The simulation and analysis of the multipath effect on antenna beam pattern measurement are presented. A simultaneous multifrequency near-field holography system operating at the W-band is built for experimental validation. Demonstrating experiment conducted on a 1.2-m aperture submillimeter antenna is reported and discussed.