Optimal Second-Order Sidelobes Suppression for Dual-Polarized Waveguide Slot Phased Array Antenna Using Array Coding

In this communication, we propose a low-sidelobe dual-polarized waveguide slot phased array antenna, operating in the X-band, based on array coding techniques. The horizontal polarization (HP) antenna array consists of two types of HP elements, featuring waveguide-to-coaxial phase inversion and radiation slot phase inversion. A genetic algorithm is utilized to optimize the array coding of these two radiation elements, effectively suppressing the second-order sidelobe levels (SOLL) of the scanning beam. Experimental results demonstrate that the antenna achieves a peak gain of 37 dBi, with sidelobe levels below −25.5 dB, HP SOLL suppressed to less than −37.12 dB, and cross-polarization isolation reaching 26.95 dB within a scanning range of ±36°. Compared to conventional arrays, the proposed design achieves second-order beam suppression improvements of 9.29–15.5 dB across the scanning range.