Design of Choke Loaded Horn Antenna Offering Stable Phase Center for Fresnel Field Based Holography Measurement

This paper introduces the new design of a choke loaded horn antenna, at 89.75 GHz for metrology of the large paneled reflector antenna using the Fresnel field based radio holography technique. The proposed choke loaded horn antenna offers the [phi] cut-wise extremely stable phase center (< 2 [micro]m), which is required to obtain < 5[micro]m surface accuracy during holographic measurement. The design of choke loaded horn antenna has been presented along with its simulation performance and tolerance analysis. The antenna has been developed using a simple computer numerical control (CNC) milling process and characterized in the anechoic chamber. The measured and simulated results are also compared, and a good match has been achieved between the measured and simulated performances of the horn antenna.