Dual-Polarized Radar Antenna with High Isolation: Polarimetric Sensing and FMCW Radar Testing

Polarimetric radars utilize dual-polarized antennas for transmitting and receiving signals with orthogonal polarizations, enabling the detection of target characteristics. This improves reliability and enhances the capability of the radar sensing system to distinguish between objects such as vehicles, stationary metallic objects, and humans, more specifically by, analyzing polarization responses. In the context of a millimeter-wave frequency-modulated continuous wave (FMCW) radar system, a new dual-polarized antenna design suitable for both single-input single-output (SISO) and single-input multiple-output (SIMO) configurations is presented at 24GHz. The antenna is a single-layer structure, and employs substrate integrated waveguide (SIW) technology. Basically, the structure comprises a network of sub-arrays arranged in a cross-shaped setup, and this design is extendable to more advanced arrays for angular target tracking and range estimation by using four possible polarization combinations of the transmitter and receiver, i.e. horizontal-horizontal (H-H), horizontal-vertical (H-V), vertical-horizontal (V-H), and vertical-vertical (V-V). The basic radar antenna is well matched from about 23.3GHz to 25.5GHz with isolation greater than 35dB. The tested FMCW radar system also successfully determined target parameters such as range and angular position.