Reflector surface distortion compensation using reflectarrays: Experimental verification

This paper presents the application of sub-reflectarray for main reflector antenna distortion compensation through simulations and measurements. A distorted dual reflector Cassegrain system is used for this study. A sub-reflectarray is used as the subreflector to form the compact Cassegrain system. A metallic ring-type distortion is created on the main reflector surface that severely distorts the radiation performance of the dual reflector system. A hybrid HFSS/PO simulation approach was used for the design and analysis. The distortions are corrected using sub-reflectarray approach by employing conjugate field matching method. A sub-reflectarray was designed and built. Bipolar planar near-field measurements are performed to measure the radiation patterns of the whole system. The sub-reflectarray compensation technique shows improved system performance in terms of higher directivity and lower side lobes.