Scan Blindness Free Design of Wideband Wide-Scanning Open-Ended Waveguide Phased Array

Abstract

A wideband wide-scanning open-ended rectangular waveguide phased array in a triangular lattice is presented. Dielectric or metamaterial wide-angle impedance matching superstrates have been widely used in phased arrays to improve the scanning performance. However these dielectric-containing covers cannot solve the problem of scan blindness caused by the surface waves, or even further aggravate the surface wave effect. The modulated surface structures, which consist of the impedance-gradient structures and the surface wave bandgap structures are designed to maximize the wideband wide-scanning performance of the array. The proposed array achieves 40% bandwidth (8–12 GHz), while covering a scanning range of ±65° in the E-plane (VSWR < 2.3) and H-plane (VSWR < 2). The practical working frequency band occupies the whole potential operating frequency band between the waveguide TE10 cutoff frequency and the onset frequency of the first grating lobe. An $11\\times11$ prototype is fabricated and measured. Good agreement is achieved between the simulated and measured results.