In calculating poles by theory

the method of moments (MoM) combined with contour integration is a common and smart one.Because of time consuming

it is usually used for the rotationally symmetric objects.In this paper

we approximate the Green’s function by Chebyshev polynomials.So

the factor of frequency can be extracted from electric field integral equation

which will largely decrease computation time in MoM at different frequencies.Then

it is possible to calculate targets’ poles of arbitrary shaped objects.Lastly

by the improved contour integration

three targets’ poles are calculated.