A quarter-mode SIW based antenna for ISM band application

In this paper, a planar substrate integrated waveguide (SIW) cavity-backed antenna is proposed for the Industrial scientific and medical radio band (5.725-5.875 GHz) at 5.8 GHz. The miniaturization is achieved by 3/4th of the conventional circular SIW cavities by using the quarter-mode SIW technique. Later on, to enhance bandwidth, a tilted rectangular-slot is etched to realize coupling of two higher order modes TM210 and TM020. The simulated impedance bandwidth and the peak gain of the proposed antenna are obtained of 350 MHz and 7.5 dBi in free space. In order to see the influence of human body on the antenna performance, it is simulated over pork muscle equivalent phantom. The impedance bandwidth and peak gain for on-phantom are obtained of 352 MHz and 7.76 dBi, respectively. The performance of the antenna does not vary from free space to on-phantom, which confirms the proposed antenna is robust and fit for off-body communication.