Focusing on the requirement of planar near-field antenna measurement, a method usually used in finite difference time domain simulation which is based on the equivalence theorem is employed in the process of near-to-far-field transformation. The distribution of the far-field pattern is obtained directly in polar spherical coordinate system. A standard gain horn antenna is taken as an example for testing. Near-field data, which are derived from theoretical formula and from numerical simulation, are transformed by this method. The results are compared with others obtained by traditional method based on plane wave spectrum expansion, analytical theory and electromagnetic computation with FDTD method. Finally, this method is proved to be reliable.
Probes coupling signal is usually ignored in traditional near-field imaging simulation, which has effect on the imaging result. This paper corrects the problem by adding coupling items in scattering equation and modifying the dis-tance between transceiver and target. Image changing with the coupling signal and the coupling distance is investigated. Background subtraction technique is used in the simulations. It is shown that, target can be focused correctly when the distance satisfies specific conditions.
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