Design For A Compact Vehicular Antenna Of Mobile Satellite Communications

With the rapid development of satellite communication technology, the STOM(Satellite-communication-on-the-move) is built in mobile carrier such as cars, trains, planes, ships, and can guarantee two-way communication of the carrier and satellites when the carriers are moving, it’s playing an essential role in many areas, such as rapid response to public emergencies, emergency command, instant messaging etc, and have broad application prospects in the field of military and civilian.With the constant development of the STOM, at the same time, mobile satellite antennas are also constantly innovative technology as an important part of the STOM. The conventional reflector antenna of the STOM is bulky, heavy, and difficult to adjust. It’s not suitable to transplant them directly into the mobile carrier, because they usually take large space and heavy, which affects the maneuverability of vehicle and limits the vehicles through the bridges, tunnels and culverts. Planar antenna has many advantages, including low-profile, compactness, light-weight efficiency etc. therefore, the research direction of STOM antenna from the reflector antenna turns to the planar antenna, this paper specific to national defense communication engineering. A dual-polarized,efficiency,symmetrical pattern, high-gain, low-profile and compactness STOM planar array antenna is designed, and it has been applied.The main contributions and innovations of this paper are summarized as follow: 1) Comparative analysis of the advantages and disadvantages of several STOM antennas. According to the requirements of the project, a design plan of compact 4 * 4 unit STOM planar array antenna is proposed, this array antenna transmit / receive units share the same radiation surface and transceiving feed network are independently. 2) The transmit / receive power divider network is designed, in order to broaden the bandwidth, adopted the combination of multiple and single section impedance matching method within the limited space. 3) The theory of multiple step impedance matching restrain high order mode can be used to implement rectangular waveguide to circular waveguide transition, finally completed the design of orthogonal mode. 4) In order to improve the symmetry of array antenna pattern and get more consistent side lobe level performance in each azimuth plane,this dissertation proposed a more symmetrical pattern of new octagon horn relative to conventional conical horn,through reasonable set octagon horn flare angle to improve gain, in the case of array elements spacing is too large, it eliminates the grating lobe and gets acceptable side lobe level performance in each azimuth plane of the array antenna 5) Using pattern product theorem calculated array antenna pattern. Comparative analysis of the performance of array antenna, which consists of different array elements, completed antenna production, and analysed the test data.