Study Of Vehicle Satellite Communications And Navigation Antennas

Recently, as the research hotspot of numerous communications technologies, satellite communications and satellite navigation have developed rapidly. It is well-known that antenna is one of the essential equipment in satellite communication system and satellite navigation system. What the paper study are just vehicle satellite communications antenna and wideband satellite navigation antenna, the detail contributions are listed as follows:The electrical performance of vehicle satellite communications antenna are that VSWR less than 2:1, Axis Ratio less than 3d B and Gain must more than 10 d Bi during the uplink band 1.970~2.000 GHz and the downlink band 2.160-2.190 GHz. In order to meet the requirements, some measures were adopted. Firstly, the antenna element adopt two patch stacked structure so that can enhance the Impedance bandwidth and Axial Ratio bandwidth by double-peak resonance. Secondly, the entire antenna consists of four antenna elements and use continuous rotation technology. Lastly, one in four double Tsplitters was used to feed the antenna elements. Each element have equal amplitude excitation and phase difference followed 0°、90°、180°、270°by clockwise order. Both of simulation and experiment results shown that the antenna can satisfy the abovementioned technical indicators.Satellite navigation antenna is moving in the direction of multi-mode and multi-band. The antenna in chapter four is a broadband satellite navigation antenna that cover most band of GPS、GLONASS、GALIEO and BD. Folded monopole was used as the radiating element due to it can obtain broadband impedance and horizontal polarized wave. The feed network connected with the antenna consist of Wilkinson power splitter, 90 °broadband phase shifter, 180°broadband phase shifter. It has broadband amplitude and phase properties. The simulation results show that the antenna can achieve VSWR less than 2:1, Axial Ratio less than 3d B and good wide beam characteristics during 1.1GHz~1.7GHz. So that it can meet well requirements of satellite navigation antenna.