Interferometric millimeter wave and THz wave doppler radar

摘要

A mixerless high frequency interferometric Doppler radar system and methods has been invented, numerically validated and experimentally tested. A continuous wave source, phase modulator (e.g., a continuously oscillating reference mirror) and intensity detector are utilized. The intensity detector measures the intensity of the combined reflected Doppler signal and the modulated reference beam. Rigorous mathematics formulas have been developed to extract bot amplitude and phase from the measured intensity signal. Software in Matlab has been developed and used to extract such amplitude and phase information from the experimental data. Both amplitude and phase are calculated and the Doppler frequency signature of the object is determined.

主权项

1. A Doppler system for detecting an object, comprising:
a continuous millimeter or terahertz wave source; a millimeter or terahertz wave beam splitter positioned to receive a continuous millimeter or terahertz wave beam from the continuous millimeter or terahertz wave source and split the beam into an object beam directed to the object and a reference beam directed to a smooth phase modulator; the smooth phase modulator with modulation frequency larger than twice the Doppler frequency of the object; the reference beam having a Low-Frequency-Band (LFB) Doppler signature modulated to a High-Frequency-Band (HFB) Doppler centered at a reference frequency of the smooth phase modulator; a reflected signal from the object having a determined amplitude and phase; and a millimeter or terahertz wave intensity detector positioned to receive the modulated reference beam and the reflected signal; wherein the Doppler frequency signature of the object is determined based upon the determined amplitude and phase and each higher-order harmonic High-Frequency-Bands (HFBs) of the reference frequency is recognized.