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Fourier Subdomain Contrast Source Inversion Method for Solving Electromagnetic Inverse Problems

In this letter, the contrast source inversion (CSI) method is modified by utilizing truncated Fourier representation and the proposed method is named as Fourier subdomain contrast source inversion (FS-CSI) method. Three main contributions of this letter are as follows. First, the frequency spectrum of contrast source is investigated. Based on Fourier theory, we come to a qualitative conclusion that the frequency content of contrast source is concentrated at low frequencies when dealing with typical targets. Third, this work tests the FS-CSI using the known ‘Austria Profile’, which proved that the proposed FS-CSI is effective and efficient. The numerical results demonstrate that the proposed FS-CSI is significantly faster than the original CSI, with saving about 50% computation time, while the reconstructed image qualities are almost the same.