We describe and compare two types of microwave sky simulations which are good for small angular scales. The first type uses expansions in spherical harmonics, and the second one is based on plane waves and the Fast Fourier Transform. The angular power spectrum is extracted from maps corresponding to both types of simulations, and the resulting spectra are appropriately compared. In this way, the features and usefulness of Fourier simulations are pointed out. For $ell geq 100$, all the simulations lead to similar accuracies; however, the CPU cost of Fourier simulations is $sim 10$ times smaller than that for spherical harmonic simulations. For $ell leq 100$, the simulations based on spherical harmonics seem to be preferable.
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