Study of terahertz LFMCW imaging radar of the heterodyne and homodyne scheme

A summary of the terahertz imaging radar of the heterodyne and homodyne scheme is presented, with an emphasis on the differences between the two schemes. The transmitters employ Direct Digital Waveform Synthesis (DDWS) in the baseband so that the reliable fast scanning frequency synthesizers are obtained to meet the fast imaging requirement. The scanning speed is 40us with an instantaneous bandwidth of 14.4GHz. To optimize the range resolution of the radars, the calibration methods for the two schemes are shown respectively according to different architectures. The pulse compression results are shown to verify the effectiveness of the two schemes. The differences between the two schemes are analysized from different aspects.