Improved numerical strategies for rigorous analysis of microstrip antennas

Rigorous calculation of microstrip structures via Galerkin Method (Finite Element) is usually restricted to mainframe computer systems or at least powerful workstations. Implementation on small PC´s is difficult due to large computation time and large memory requirements. The first problem is overcome by using combined integration techniques in conjunction with closed form subtraction of asymptotic parts of the integrand or suitable deforming of the integration path. By wing iterative techniques for solving the linear system the required memory even for large structures is dramatically decreased. The methods are demonstrated on microstrip antennas but are also capable to deal with arbitrarily shaped multilayered microstrip structures. The time needed for a frequency point is approximately one minute on a PC486/33MHz computer, which was approximately the time to solve the same problem conventionally on a CRAY Y/MP in the past. Accuracy of the computed techniques presented is verified experimentally.