Electromagnetic detection and imaging transceiver (EDIT) and roadway traffic detection system

摘要

An automatic frequency control is used to keep a continuous wave (CW) transmission tuned to the resonant frequency of a resonant microwave patch antenna (RMPA). Changes in loading and the bulk dielectric constant of the mixed media in front of the RMPA will affect its resonant frequency and input impedance. A significant shift in the measured input impedance is interpreted as an object moving nearby, and the phase angle of the measured input impedance is used to estimate the direction of an object's movement.