Broadband Dual Polarized Space-Fed Antenna Arrays with High Isolation

This paper presents a novel design of dual polarized space-fed antenna arrays with broad bandwidth and high isolation between two orthogonal ports. The dual polarized space-fed antenna arrays are designed with bottom radiating element electromagnetically coupled to two orthogonal open microstrip lines and top parasitic elements excited by the radiation from bottom radiating element, without any feed network for array elements excitation. Two space-fed antenna arrays with 7 and 19 parasitic elements, respectively, have been designed for 5.8GHz frequency band and their performances are analyzed. The dual polarized space-fed array with 19 parasitic elements has been fabricated, and its performance is measured. The measured impedance bandwidth is 10.7%, isolation ≥ 32 dB between two orthogonal ports over entire bandwidth, maximum gain of 17.8 dBi and cross-polar levels ≤ −29 dB.