Design of a Low-Profile Wideband Wide-scan Phased Array Antenna

A low-profile phased array antenna with wideband wide-scan characteristics has been presented. An aperture coupled feed mechanism and dual-layer radiating patches are adopted to achieve wideband impedance matching. Due to the piled dielectric slabs, the performance of microstrip antenna arrays is normally deteriorated by surface waves when scanning to large angles. To solve this issue, the stacked slabs have been perforated to the greatest extent to suppress surface wave propagation. Additionally, two pairs of parasitic strips have been designed to improve the antenna performance in the lower band without increasing the antenna profile. The thickness of the array is only $0.19\lambda_{h}(\lambda_{h}$ refers to the wavelength at the highest operating frequency in free space), indicating the good potential for low-profile applications. The proposed array antenna has achieved relative bandwidths of 57.9% (active VSWR $\leqslant 2.25$) and 44.4% (active VSWR $\leqslant 2.75$) for $\pm 45^{\circ}$ scanning and $\pm 60^{\circ}$ scanning, respectively.