Analysis and Design of Wide-Scan Angle Wide-Band Phased Arrays of Substrate-Integrated Cavity-Backed Patches

A class of wide-scan angle wide-band microstrip patch phased arrays is proposed. The proposed phased arrays are composed of probe-fed microstrip patches backed by substrate-integrated cavities. First, a simplified 2-D numerical analysis based on Floquet's theorem is presented to qualitatively demonstrate the E-plane scan performance of the cavity-backed structure compared to that of the conventional microstrip patch phased array. Second, the 3-D scan performance of the proposed phased arrays is thoroughly investigated varying both the substrate thickness and dielectric constant using commercially available EM simulation tools, which is followed by presenting simple design guidelines for the cavity, patch and substrate. A 7x7 prototype phased array of the proposed SIW cavity-backed patch structure was fabricated and its measured results agree well with our theoretical prediction and indicate a relatively wide-scan performance when compared to the corresponding microstrip patch phased array without cavities.