Millimeter-Wave High-Gain SIW End-Fire Bow-tie Antenna

This communication presents a high-gain bow-tie antenna that operates across 57-64 GHz for application in high data rate point-to-point communication systems. The proposed antenna consists of a pair of bow-tie radiators, where each radiator is etched on the opposite side of the common dielectric substrate and fed through substrate integrated waveguide (SIW) feed-line. The bow-tie radiators are arranged to cross each other symmetrically by tilting the feed-lines by 30° to enhance the antenna gain and to obtain the required radiation pattern. The antenna is loaded with a pair of double G-shaped resonators (DGRs) that are located in a region between the radiators and SIW to suppress the back-lobe level in the H-plane. Embedded in the E-plane of the antenna is an array of zero-index metamaterial (ZIM) unit-cells whose purpose is to effectively confine the electromagnetic waves in the end-fire direction to enhance its gain performance. A prototype antenna was fabricated and its performance was measured to validate the simulation results. The proposed structure exhibits a gain of 11.8-12.5 dBi over the frequency range of 57-64 GHz with reflection coefficient less than $- 11;hbox{dB}$. In addition, the proposed antenna exhibits good cross-polarization, which is less than $- 17;hbox{dB}$ in both E- and H-planes at 60 GHz.