Influence of 2-D Transceiver Array Aperture Size and Polarization on 3-D Microwave Imaging of Subsurface Objects Under Born Approximation

This article utilizes the spectral analysis method to investigate the influence of 2-D transceiver array aperture size and polarization on 3-D qualitative microwave imaging of subsurface objects. The investigation is performed in three steps. First, in the framework of the integral equation with Born approximation (BA), we derive the analytical relationship between the 2-D spectra of the scattered electric fields and the reconstructable 3-D object spectrum, which is weighted by a vector coefficient related to transceiver polarization. The theoretically reconstructable 3-D spectrum is analyzed. Second, to obtain the 3-D spectrum for more practical microwave imaging measurement with the wave attenuation, the evanescent mode contribution, and the transceiver polarization considered, we perform the singular value decomposition (SVD) to compute the discretized integral operator right-singular function whose spectrum reflects the reconstructable 3-D spectrum. It is shown that the mutual coupling in two orthogonal horizontal directions leads to the vertical "allpass" feature and the horizontal "lowpass" feature in one vertical 2-D plane if the array aperture size in the orthogonal horizontal direction is large enough. Meanwhile, the transceiver polarization also has obvious effects on the reconstructable spectrum. Third, numerical experiments are implemented to verify the relationship between the transceiver array configuration and the reconstructable spectrum.