Design Considerations for Near to the Ground Communication System and Associated Sub-GHz Low Profile Antenna

Abstract

This paper presents propagation aspects of a peer-to peer communication link where antennas are placed near to the ground ( low height). First, some of the propagation models are evaluated for understanding of propagation mechanisms. In this regard, as the height of the antennas are very low and the distance is large enough, reflecting angle becomes very small that makes use of two ray model. On the other hand, in the horizontal plane, the positions of the scattering objects, as a source of lateral waves, might vary largely due to the terrain undulations along with variety of objects around the link. This makes propagation mechanisms a little bit complicated. In order to design low profile, high gain sub-GHz antenna for such propagation environment, microstrip antenna with vertical ground was designed and fabricated. The antenna is required to be protected from natural and man-made effects. Therefore, the antenna with associated sensors are embedded into a metal box with a dielectric cover. All these are discussed and some of the findings are presented.