A Novel Method for 3-D Millimeter-Wave Holographic Reconstruction Based on Frequency Interferometry Techniques

A novel interferometry technique is proposed and introduced into active millimeter-wave (MMW) holography. Different from optical holographic interferometry, which relies on a reference light source or the interferometric synthetic aperture radar where data from apertures of different elevations are interfered, data are interfered between different frequencies in the proposed method. Higher ranging accuracy is achieved, since the residual phase information which is always neglected is utilized by the interferometry manner. The proposed method also avoids interpolations in the traditional MMW holographic imaging algorithms, by which the computational complexity can be reduced. First, theoretical derivation of the 3-D reconstruction method based on frequency interferometry is presented, and detailed algorithms considering noise resistance and phase unwrapping are designed. Then, numerical simulations are conducted to validate our methods. Different aspects of the proposed algorithms' performance are analyzed and compared with previous methods. Finally, laboratory experiments are carried out. Both the simulation and experimental results validate the superiority of our method on reconstruction accuracy and computational efficiency.