Millimeter Wave/5G Multiband SIW Antenna with Metasurface Loading for Circular Polarization and Bandwidth Enhancement

In this paper, a triple-band cavity-backed substrate integrated waveguide (SIW) based slot antenna operating in the millimeter-wave region is proposed. The advantage of reduced fabrication complexity and ease of integration with planar circuits are the reasons for realizing cavity-backed slot antenna using SIW technique. A novel modified spiral slot resonator (MSSR) etched at the top along with tilted slots results in the creation of three bands. The performance of the proposed antenna is further enhanced by stacking a metasurface thereby resulting in circular polarization at 30 GHz and enhancement of bandwidth of the third band from 3.37 to 7.62%. The metasurface has 110 unit cells arranged in a 10 × 11 configuration. The MSSR-based SIW antenna stacked with the metasurface yields three bands, 22.389 GHz to 23.562 GHz (5%), 29.73 GHz to 30.239 GHz (1.69%), and 36.105 GHz to 38.968 GHz (7.62%). Measured results are in good agreement with their simulated counterpart. The maximum radiation efficiencies are 88.37%, 88.63%, and 89.85% in the operating bands of 22.389 GHz to 23.562 GHz, 29.73 GHz to 30.239 GHz, and 36.105 GHz to 38.968 GHz, respectively. Measured peak gains in the three operating bands are 7 dBi, 8.5 dBi, and 14.5 dBi respectively. Radiation patterns at the three operating bands are uni-directional owing to cavity-backed design.