Wideband Wide-Scanning Phased Array With Connected Backed Cavities and Parasitic Striplines

A novel wideband wide-scanning phased array is presented in this paper, in which a new cavity-backed array element is employed. The proposed element consists of a probefed open-ended microstrip line backed by an open cavity and four parasitic metal striplines printed on the upper super-strate. It presents the advantages of compact size, simple feed structure, and low profile. The dual-resonance behavior of the proposed element results in a simulated bandwidth of 53.5% (7.8-13.5 GHz) for VSWR <= 2. To compose the array, the open-backed cavities of adjacent antenna elements are connected rather than isolated to each other. The infinite array unit cell achieves about 43.4% bandwidth (7.4-11.5 GHz) with active VSWR <= 2 when scanning up to +/- 60 degrees, and nearly 44% bandwidth (7.45-11.65 GHz) with VSWR <= 2.5 when scanning up to +/- 70 degrees in all azimuth planes. For verification purpose, a 2 x 18 array prototype is fabricated and it experimentally achieves nearly 51% bandwidth (7.2-12.1 GHz) with VSWR <= 2.3 as scanning to 60 degrees, and more than 54% bandwidth (7.2-12.5 GHz) with VSWR <= 3.2 up to 70 degrees in the H-plane, showing close agreements with simulations.