Use moment method with sub-domain function to compute the parameters of double-layer microstrip antenna

For the expansion of the theoretic analysis on the applicable antenna, this paper uses moment method with sub-domain functions to compute the parameters of double-layer microstrip antenna. The method divides this antenna gap into many regions for basic functions, and the moment method technique is used to obtain parameters of antenna. As compared with cosine function used, the data obtained by computation with sub-domain squared function, such as frequency, electric field distributions within gap and cavity, has similar trend. Therefore, the parameters of antenna obtained by this method are acceptable. The sub-domain function is suitable for other microstrip antenna with complicated structures.