Design of Dual-Polarized Shared-Aperture Waveguide Slot Antenna Array

As one of the key subsystems of the synthesis aperture radar (SAR) system, the antenna needs to have characteristics such as broadband, multi-polarization, and active phase control. Waveguide slot array antennas are widely used in radar and electronic communication fields for their low cross-polarization, compact structure, easy processing and installation. In this paper, a dual-polarized shared-aperture waveguide slot antenna operating in X-band has been designed as subsystem of SAR. An effective design method to realize the shared aperture of two polarized waveguide slot antenna arrays is proposed. The structure layout of the antenna array is optimized by this method, which ensures that the sub-arrays of both polarizations have excellent performance. The narrow beam antenna array operating in X-band has vertical and horizontal polarization half power beamwidths of $6 ^{\circ} \times 6.64 ^{\circ}$ and $5.85 ^{\circ} \times 7.11 ^{\circ}$, respectively, and the measured gains of the two polarization modes are both higher than 28dB. This kind of array arrangement makes full use of the space and improves the performance of the entire array. Because the beam width and gain of the antenna array meet the requirements, it has achieved good performance in the actual test.