Scattering and radiation analysis of microstrip antennas using discrete complex image method and reciprocity theorem

A simple and efficient method is presented to characterize the scattering and radiation properties of arbitrarily shaped microstrip patch antennas. The method employs the discrete complex image technique to circumvent the time-consuming evaluation of the doubly infinite integrals in the spectral domain method of moments. Furthermore, the method calculates the scattered/radiated fields using the reciprocity theorem, which is found to be more straightforward than the commonly used stationary phase method. Numerical results are presented for arbitrarily shaped microstrip antennas and arrays to demonstrate the accuracy and efficiency of the method.