Semi-analytical calculation for sensitivities of the method of moments impedance and excitation matrices
A novel method is presented in this article for calculating the sensitivities of the impedance and excitation matrices of the method of moments. The proposed method evaluates the required derivatives with respect to a design variable semi-analytically. It is demonstrated that one matrices' fill is enough to achieve the required sensitivities. Two such fills would be necessary to obtain similar results using the conventional finite-difference approximation method. A microstrip patch antenna example is used to demonstrate the validity of the proposed method. By comparing its results with those obtained using finite-difference numerical approximation, a high degree of agreement is observed. The accuracy of the numerical approximation is found to be sensitive to the selected value of perturbation. (c) 2007 Wiley Periodicals, Inc.
sensitivity method of moments microstrip patch antennas excitation matrix impedance matrix em-based optimization