A planar end‐loaded dipole phased array with enhanced bandwidth and wide‐angle scan

Abstract

A bandwidth-enhanced wide-angle scanning phased array based on planar end-loaded dipole elements is designed and analyzed in this paper. Initially, the phased array is designed based on wideband wide-beam dipole elements, which are placed in a hybrid artificial structure composed of surface waveguide (SWG) and high-impedance surface (HIS). An additional resonance caused by surface-wave propagation in the SWG is generated close to the dipole resonance. The dual-resonance mechanism improves the impedance bandwidth. Then, in order to enhance the array active reflection performance, the HIS is adopted to reduce the coupling between array elements which is caused by the excited surface waves. Besides, the SWG-HIS hybrid structure has a zero-phased reflection in the phased array operation band, which contributes to the wide-angle scan. The total dimension of the proposed eight-element phased array is about 3.24 λ0 × 0.675 λ0 (λ0 is the free-space wavelength at 4.5 GHz). The phased array shows a main-beam scan up to ±60° with a realized gain higher than 8.8 dBi and a total efficiency higher than 84% in an active reflection band of 4.35 ~ 4.85 GHz.