Improved bandwidth microstrip antenna design for airborne phased arrays

A microstrip radiating element design for a 10% bandwidth, wide-scan-angle, phased-array antenna is described. The radiating element consists of a single probe-fed circular patch on a thick substrate. The element match is optimized using a waveguide array simulator. A finite array of 108 elements was fabricated to evaluate the array's scan-angle performance. Mutual coupling data were used to compute the element reflection coefficient as a function of frequency and scan angle. The scan angle performance was compared with that obtained using the theoretically computed mutual coupling coefficients of a similar array. Both analytical and measured results showed high voltage standing-wave ratio (VSWR) at wide scan angles. The array's performance with a dielectric cover on the top has been evaluated both analytically and experimentally. The results show improvement in the scan angle performance over 10% bandwidth.<>