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

Abstract

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 superstrate. 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 openbacked 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°, and nearly 44% bandwidth (7.45-11.65 GHz) with VSWR ≤2.5 when scanning up to ±70° in all azimuth planes. For verification purpose, a 2 × 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°, and more than 54% bandwidth (7.2-12.5 GHz) with VSWR ≤3.2 up to 70° in the H-plane, showing close agreements with simulations.