Research On Key Technologies Of High-precision Measurable Antenna

With the fast development of satellite navigation technology, the high-precision measurable terminals have been widely utilized. As an important component of satellite navigation receiver, the performance of high-precision measurement antennas is directly related to the measurement accuracy of satellite navigation receiver. Besides the VSWR, radiation pattern, gain, the axial ratio and etc, high-precision measurement antennas are also concerned for the antenna phase center stability, multipath rejection and low elevation gain. Both high antenna phase center’s variation and weak multipath rejection can reduce the measurement precision. A lower low elevation gain of the antenna can affect the quality and quantity of the satellite search, which will have effect the calculation of backend module to the satellite signal in turn. In this thesis, the design of high-precision measurement antenna based on the theory of microstrip antenna is discussed.Firstly, the development history of satellite navigation system and status of high-precision measurement of antenna are given, and the basic theory of microstrip antennas is introduced. Secondly, a multi-mode satellite navigation microstrip antenna is designed. The antenna can cover four navigation systems, i.e. GPS, BDS, GLONASS and GALILEO. Meanwhile, using the two-layer structure, the multi-feed technique and matching network are used to ensure good performance of the antenna.Then, the choke ring which is an effective method to mitigate multipath effect is analyzed. Surface impedance model is used to analyze boundary conditions of choke ring to find out basic rules of choosing choke ring parameters. Using the design of two-layer choke ring can reduce the volume of the antenna to an extent. The variation of choke antenna performance with choke ring parameters is analyzed by simulation. The low elevation gain is improved by using the method of joining conductive ring and the ability of multipath rejection maintain strong simultaneously. A miniaturized 3D choke ring is manufactured according to the above parameters analysis results. The measured results show that the 3D choke antenna has stable phase center, excellent multipath rejection and higher low elevation gain.