Electro-Optic Heterodyning Technique for 79 GHz Automotive Radar Antenna Measurement

In this paper, a precise and compact antenna measurement system for automotive radar antenna operating at 79 GHz is proposed. A planar field imaging system with an electro-optic sensor is developed to measure magnitude and phase in the reactive near-field region of the array antenna. A detailed electro-optic heterodyning technique to measure vectoral electric field distribution at the W-band is discussed. To validate the performance of the proposed planar imaging system, a comb-line array antenna characterization at 79 GHz is conducted. The radiation far-field pattern and gain, calculated from the near-field measurements, are in good agreement with each other according to a comparison of these outcomes.