Half mode substrate integrated waveguide based leaky wave antenna with low cross polarisation

Abstract

A half mode substrate integrated waveguide (HMSIW) based leaky wave antenna (LWA) featuring low cross-polarization is proposed in this paper. The umbrella-shaped slot (the combination of longitudinal and transverse slots) is etched on the top layer of HMSIW LWA to get the efficient broadside radiation. The scanning range is obtained from −47° to +30° in a frequency range of 8.3 to 15.1 GHz. The cross-polarization level for the LWA is around −10 dB at broadside. In order to improve the cross-polarization levels in HMSIW LWA, two antennas are placed face to face obtaining the balanced symmetry across the longitudinal axis. Both the simulated and measured results show that the antenna is able to scan continuously from backward to forward direction with a very good low cross-polarization level. The developed prototype is capable of continuous beam scan from −29° to +32° in an operating frequency band of 9.2 to 15 GHz with a maximum gain of 13.5 dBi. The measured cross-polarization level is −30 dB which is quite low for the main beam at the broadside direction.