Wideband and Gain Enhancement SIW Slot Array Antenna Using Sparsification Processing and Composite Metasurface

In this communication, a substrate-integrated waveguide (SIW) array antenna based on sparsification processing and a composite metasurface is presented. Through the sparsification processing which is the main innovation of this design and reasonable optimization of the radiating slots, the mutual coupling is weakened, the bandwidth is eventually widened, the sidelobe is reduced, and the bandwidth is increased by 210 MHz. On this basis, by introducing the composite metasurface consisting of a radiation patch and parasitic patch, the operating bandwidth of the antenna subarray is further extended and the gain is improved. Compared with the original antenna subarray, the bandwidth of the designed subarray is increased by 8.9%, the sidelobe is decreased by 5.4 dB, and the gain is enhanced by 3.58 dBi. To verify the correctness of the design, a
$1 \times 8$
uniform excitation array is proposed and fabricated, containing three SIW T junctions and four Y junctions. Simulated and measured results imply that an 8.75-10.82 GHz (21.2%) impedance bandwidth can be achieved with a maximum gain of 21.61 dBi.