Usage of multiport reflectometer in the construction of Doppler radar system for measuring very low velocities

By using the multiport in the Doppler radar system, no circulator or mixer is needed for the phase measurement. Furthermore, the usage of multiport reflectometer and statistical calibration approach, the overall precision and operation speed of the system can be improved greatly. Simulations and preliminary experiments have been conducted to verify the validity of the proposed scheme and to investigate the frequency characteristics of the proposed system. The investigations demonstrate that the target velocity around 0.2 mm/s has been successfully inferred, which shows a great potential for the multiport technique in the future design and implementation of Doppler radar systems.