'Institute of Electrical and Electronics Engineers (IEEE)'
Abstract
Microwave imaging has been developed recently and
is used in many applications. Kirchhoff’s migration technique
is one of the most popular methods to recover the geometric
info of any inaccessible target from raw data. The conventional
Kirchhoff’s migration assumes a uniform propagation velocity
in the far-field region of the transceiver, i.e., the antenna. In
the near-field region of the antenna, the pulse propagation
happens at a significantly greater speed compared to the farfield region. The propagation speed of the pulse depends on the
antenna dimensions and varies as a function of the distance and
angle of the antenna in a non-linear manner. This non-linearity
causes non-focused images. In this work, a modified Kirchhoff’s
migration method is proposed to take into account the nonuniformity of the propagation speed. Then, the proposed method
is verified through several simulations and experiments and it is
shown that the modified Kirchhoff’s migration results in focused
images in the near-field region
