Study of terahertz LFMCW imaging radar with Hilbert transform receiver

A linear frequency-modulated continuous-wave (LFMCW) radar with a simplified single homodyne channel is proposed and developed in the 0.22 THz band. The transmitter employs direct digital waveform synthesiser technology to obtain a reliable fast scanning LFMCW source, the scanning speed of which is 40 s with an instantaneous bandwidth of 14.4 GHz. To realise the nonlinearity calibration and coherent imaging, the quadrature signal is recovered by a Hilbert transform receiver to obtain the phase information of the return wave. The radar operates using the real-aperture imaging method and uses a lens to focus the Gauss beam which determines the azimuth resolution. The results of the pulse compression and imaging experiments verify the effectiveness of the proposed imaging scheme in the 0.22 THz band. The radar can be used for non-destructive testing and security checks.