Comparative Investigation of Half-mode SIW Cavity and Microstrip Hybrid Antenna Using Different Patch Shapes

Abstract

A set of hybrid microstrip patch and semi-circular cavity antennas is introduced. The semi-circular<br><br>cavity is implemented using Half-mode Substrate Integrated Waveguide (HMSIW) technique.<br><br>Different shapes of the patch including rectangular, semi-circular and equilateral triangular are excited<br><br>using proximity effect by the semi-circular SIW cavity at its TM010 mode. The proposed antenna<br><br>structures have been excited using an inset 50 W microstrip line that leads to facility of planar circuit<br><br>integration. The inherent limited bandwidth of the conventional microstrip patch antenna and SIW<br><br>cavity-backed slot antenna is improved about 6% to 10% depending on the type of the patch using the<br><br>proposed structure. Additionally, the proposed hybrid antenna enhanced the antenna gain by about 1.5<br><br>dB in comparison with the half-mode cavity without patch. Meanwhile, the proposed hybrid antennas<br><br>are made on a single-layer substrate has a low fabrication cost using printed circuit board (PCB)<br><br>process. Three hybrid antennas are numerically and experimentally investigated. A comparative study<br><br>between the three different structures contains gain, bandwidth, Cross Polarization Level (CPL) and<br><br>Front to Back Ratio (FBR) is presented.