A Novel High-Gain Hexagonal Cavity-Backed MIMO SIW Antenna With 3-D Homogeneous Lens Loading at Ka Band

In this letter, a novel symmetrical hexagonal-shaped cavity-backed substrate integrated waveguide (SIW) antenna with 3-D lens is presented. The novelty of the proposed design is achieving a gain of approximately 20 dBi from single unit cell lens SIW antenna. The proposed 4 × 4 multiple-input–multiple-output (MIMO) SIW lens achieves a high isolation above 30 dB for the operating band with high gain. The proposed MIMO SIW lens antenna achieves a −10 dB bandwidth of 1.1 GHz (27.89 GHz to 29 GHz). It is achieved by a pair of parallel slots on top of the SIW cavity. The proposed design offers a simulated gain of 6.5 dBi, which was then enhanced to 18.5 dBi at 28.4 GHz with the integration of a 3-D-printed dielectric homogeneous lens. The cavity-backed lens antenna is used to realize a 4 × 4 MIMO antenna structure. The 4 × 4 MIMO SIW lens antenna has isolation above 30 dB (between the four antenna elements) throughout the frequency band of operation. The measured results are in good agreement with Ansys HFSS simulations. The stable antenna performance makes it suitable for applications in satellite, radar imaging, and point-to-multipoint wireless communications.