Optimal Design, Based On The Method Of Moments Microstrip Antenna

With the fast development and the wide application of the modern wireless communications technology, the communications systems are required to be compact and high-performance. The design of compact and heigh-performance microstrip antenna is becoming one of the most advanced subjects at home and in the world. In this dissertation, the problems that how to increase the band width, how to improve gain of the microstrip antenna, and how to reduce the mutual coupling between microstrip antennas are studied based on the method of moments(MOM).The dissertation is classified into three parts stated as follows.Firstly, the integral equation of the infinite floor model, which is solved by the method of moments, is derived based on the reciprocity theorem; otherwise, to simplify the probe feed model ,the finite floor model of the microstrip antenna is analyzed based on the volume and surface integral equation(VSIE).The algorithm are validated by contrasting the results with the results of the HFSS and the experiment.Secondly, the genetic algorithm(GA) is used for optimizing the bandwidth via changing the patch shap. The short rectangular patchs divided by the patch are coded and operated by genetic algorithm operation, and than the patch will besatisfy the certain request of the band width. Because the impedance matrix and the chromosome code string are all related with the element of the divgision, and the pulse base function is corresponding with the rectangular unit, it is easy to calculate. this dissertation discusses two microstrip antennae different thickness medium, and the optimization results show the effectiveness of the algorithm.At last, the unit spacing and cell size of the electromagnetics band-gap(EBG) are studied with the equivalent circuit model. this dissertation studied the gain and the bandwidth effected by EBG via calculating different forms EBG structure microstrip antennae. The results show that the EBG structure wit reasonable parameters is useful for improving the gain of the microstrip antenna and increasing the bandwidth. otherwise, the EBG structure is applied into the microstrip antenna array. this dissertation calculates two different distance microstrip antenna arrays. The results shows that mutual coupling is significantly reduced from -14.4dB to -23.7dB.