A low profile and low sidelobe wideband slot antenna array feb by an amplitude-tapering waveguide feed-network

A low profile slot antenna array is designed to operate over a wide bandwidth with low sidelobe levels. Taylor synthesis is used to taper the power distribution among array aperture. An efficient approach to design an equal-phase but unequal-power symmetric waveguide divider is proposed for constructing an amplitude-tapering feed-network for the array. Phase differences are balanced by adjusting the waveguide phase velocities. The basic radiator is a 2 × 2 slot subarray, uniformly fed by such a waveguide divider. A 16 × 16 array is then constructed by 8 ×, 8 of such subarrays. A 1-to-64 way corporate-feed waveguide network is designed to excite all subarrays instead of individual slots, and the required power distribution is obtained by adopting a 30 dB Taylor & overline; N=4 synthesis. Measured results indicate that the array can achieve a 13.8% bandwidth and a gain of more than 29.5 dBi. The first sidelobe level is-26.5~ dB in the E-plane and-30.4~ dB in the H-plane. The holistic sidelobe levels in both planes are better than-25~ dB with a better than-40~ dB cross-polarization.