Broad Band Omni Directional Antenna System for Onboard Telemetry Applications

In this paper, broadband linearly polarized rectangular microstrip antenna with U-slot in S-Band frequency is designed. The antenna has been analyzed using the FEM-based HFSS software. The characteristics of an individual antenna and antenna system have been studied by placing them on a cylindrical surface of 400mm diameter to get omni-directional coverage. These antennas are flush to the surface of the cylindrical body whichfer zero aerodynamic drag. The antenna requires dielectric cover over the radiating element to protect from heat, physical damage and environmental constraints. The 10dB return loss bandwidth is around 100 MHz at 2.25 GHz. The single antenna mounted on cylindrical body has a minimum gain of 6dBi over the bandwidth. The HPBW of antenna is 72° in roll plane and 94° in its orthogonal plane. The antenna system with two antennas mounted on diametric opposite side of cylindrical body gives coverage better than 85% for dip in the pattern upto -10dB.