The effect of different testing functions in the moment method solution of thin-wire antenna problems

The use of piecewise sinusoids for expansion functions and rectangular pulses for testing functions is described in the application of the method of moments to thin-wire antennas and scatterers. This choice of expansion and testing functions allows efficient calculation of matrix elements and yields accurate results for certain widths of the testing function. However, for other widths, although the standard criteria for the selection of these functions are satisfied, erroneous results are obtained. The validity of the moment method solution can be checked by examining the near-field.