Compact four-element MIMO SIW cavity backed slot antenna with high front-to-back ratio

In this article, a novel design of single layer, compact, multiple input multiple output (MIMO) half-mode substrate integrated waveguide (HMSIW) cavity backed quad element slot antenna with high front-to-back ratio (FTBR) is proposed. The proposed antenna consists of four rectangular SIW cavities with semi-taper radiating slots. The antenna elements are placed in a fashion to achieve high isolation. This antenna is designed for WLAN vehicular communication system to cover the frequency range of 5.84GHz to 5.96GHz. It has high front to back ratio (FTBR) of more than 25dB without using any external metallic reflector. It has more than 37dB isolation in between orthogonal elements and more than 24dB in between parallel elements. The envelop correlation coefficient (ECC) and diversity gain are 0.003 and 9.99dB respectively in between all the elements. Moreover, the antenna has high gain and efficiency of more than 8 dB and 94%, respectively, in 10 dB impedance bandwidth. It can be tuned in a wide range of frequency.