Due to limitation of computer's memory and speed

many traditional numerical computational electromagnetic method such as FDTD meets difficulties in solving electrical-large objects problems.A pseudospectral time-domain(PSTD) algorithm is developed recently to overcome limitations in the conventional solution methods for Maxwell's equations.This technique uses the fast Fourier transform(FFT) algorithm for the spatial derivatives and uses the perfectly matched layer(PML) to absorb exocentric wave and eliminate the wraparound effect.Because the Fourier transform has an infinite order of accuracy

only two cells per wavelength are required

compared to 10~16 cells per wavelength required by the FDTD method for the same accuracy.In this paper

the PSTD algorithm is introduced to solve electrical-large objects problems.A perfectly matched layer(PML)for the absorption of electromagnetic waves in this algorithm is also analyzed.