Abstract: We analyze the integrand spectrum in the plane wave expansion of spherical functions,and present a standard of(2L,4L) point quadrature for spatial angles satisfying the sampling theorem.Numerical results with the method of moments(MOM) and fast multipole method(FMM) in different quadrature schemes are compared to show the validation of our quadrature scheme.

Key words: fast multipole method, spectrum analysis, spatial angle quadrature