Research On Mutual Coupling Of Array Antenna

Microstrip antenna has wide applications, and arrayed microstrip antenna is also a focused researchof the electromagnetic field. With the miniaturization trendency of device, the mutual coupling effectof array antenna elements can not be ignored: the dereasing antenna size can aggravate the energycoupling between array elements, which can lead to increasing the radation pattern of sidelobe andreducing gain of mainlobe, as well as many other unexpected results.The method of moments (MOM) is a classic algorithm of antenna analysis. In order to study themutual coupling of arrayed microstrip antenna with high accuracy, the RWG (Rao-Wilton-Glisson)basis function is introduced into method of moments to guarantee the accuracy while reducing thecomputation complexity, and effectively analyze and calcualte the impedance, current, and otherparameters, as well as radation field of array antenna.Further, the array antenna is equivalent to a port network that makes analyzing of the impedancecharacteristics more easily. Based on this method, finding mutual coupling is converted to find mutualimpedance, thus the compution of mutual coupling is simplified. In addition, a poly-populationgenetic algorithm is applied to microstrip patch line array antenna and two-dimensional planar arrayantenna, then the excitation of array element can be calculated to compensate the radiation patternaccording to the weighted vector result. On the other hand, a genetic algorithm is applied to optimizethe array antenna pattern with mutual coupling effect. All theoretic research results are proved bysimulation.In order to increase the isolation of antenna elements, and suppress the mutual coupling in thedesign of array antenna, the mechanism of electromagnetic band-gap (EBG) structure and defectedground structure (DGS) are applied to microstrip patch arrayed antenna. It provides a reliablemethodololgy for implementation of suppressing mutual coupling.