Dual-polarized beam-scanning antenna using parasitic sub-arrays

The design, fabrication and characterization of a four-element linear array of dual-polarized parasitic sub-arrays (PSAs) is described in this paper. The sub-arrays are designed to operate in the X-band and they are fed by stacked microstrip patches. Comparable to the well known Yagi-Uda principle, the PSA employs parasitic coupled radiators to increase the directivity. A wire model has been developed for a very fast analysis of the sub-arrays during the antenna design. The desired angular field-of-view (FoV) of the linear array is +/-15degrees and four PSAs, which cover this angular range, are used in the array. Algorithms for optimum beamforming are applied to the measurement results and a mean directivity of 17.5 dBi is achieved within the desired FoV. Subsequently two different schemes are used to calibrate the antenna array prior to a direction of arrival (DOA) estimation algorithm. The resulting DOA estimation error, with mean values between 0.06degrees and 0.154degrees, is then used to evaluate both calibration methods.