A Research Of Anti-jamming Array

Satellite Navigation System is playing an important role in modern life and it isbecoming one of the focuses of attention. However, because of the long distancebetween the Earth and satellites, the signal from satellites is very weak and easy tointerference caused by space or man-made. Therefore, it is very important to study theanti-jamming technology in theoretical field and practical applications.This paper deals mainly with some aspects on anti-jamming array, expecially onthe circular polarization realization of the microstrip antenna, array design, and mutualcoupling reduction. The main contribution is as follows:Firstly, the characteristics and shapes of circular polarization antennas aredescribed, and the circular polarization microstrip antenna technology is emphasized.Then, the analytic and design theory of the microstrip antenna is discussed, includingthe design of the patch and the feeding technology. Based on the theory, a two-fed and afour-fed circular polarization antenna are designed, and the detailed procedure is given.According to the design requirements, the two-fed circular polarized antenna is selectedas the element of the anti- jamming array.Secondly, a detailed description on how to choose the number of the elements, thespace between them and the arrangement in the anti-interference antenna array isshowed. The focus is on the study of the location of the antenna element and feedingpoints, which have an impact on the radiation pattern, and some methods on how toeliminate the influence is proposed. Considering a 2*2 anti-jamming antenna array forexample, the nulling process is described, which is validated with the High-FrequencyStructure Simulation Software (HFSS).Finally, the mutual coupling in the antenna array is analyzed in detail and twopossible technologies to eliminate the mutual coupling is proposed. The one is to placeabsorbing materials between the antenna elements in order to absorb theelectromagnetic wave. The other is to insert the EBG structure to generate the stopband.The design procedure is given in detailed and computer adied design and analysis arecarried out by Ansoft HFSS. The antenna array is fabricated and measured, and theresults show that both the two methods can effectively decrease the mutual couplingbetween antenna elements.