Terahertz Imaging Radar With Inverse Aperture Synthesis Techniques: System Structure, Signal Processing, and Experiment Results

The combination of the all solid-state terahertz (THz) technology and synthetic aperture radar imaging technique leads to small imaging sensors of high resolution. In this paper, we present an active frequency-modulated continuous-wave THz imaging radar system with inverse aperture synthesis technique to image objects in centimeter-scale resolution in two dimensions. Its high-range resolution is achieved through the use of broadband sweep signal, whose frequency ranges from 336.6 to 343.8 GHz, and the 1-D aperture synthesis enables the improvement of the cross-range resolution. In order to optimize the range resolution, a nonlinearity calibration approach is presented to solve the signal distortion. To verify the imaging performance of the THz radar, the inverse synthetic aperture radar experiments are performed and the imaging results obtained by the 2-D fast Fourier transform method and back-projection algorithm, respectively, show that the THz radar can achieve high resolution in the range and azimuth dimensions.