Design Of Vehicular Millimeter Wave Radar Array Antenna Based On Metamaterial

In recent ten years,the trend of car ownership has been growing rapidly,and the safety performance of cars has been widely concerned.As an important part of automobile safety defense system,vehicle-mounted radar has attracted much attention from researchers and manufacturers.The millimeter wave(MMW)radar has become the mainstream of vehicle-mounted radar research and development at the current stage with excellent advantages such as all-weather,high-precision and compact size.As the transceiver of radar,the antennas directly affect the detection performance of MMW radar,so the realization of broadband,low-cost and high-performance MMW radar antenna is still a research hot topic.In view of the above intention,two lens antennas of two frequency bands of 24GHz and 77GHz were composed in this paper.First,a transmission metasurface element was designed based on a three-layer double-coaxial metal ring structure.The entire 2?transmission phase range was covered by adjusting the inner and outer radius of the two metal rings.The metasurface units were arranged into 6×1 and 8×1electromagnetic deflection metasurface arrays according to the phase gradient,which can realize the deflection of electromagnetic waves at different angles in different frequency bands near 24GHz.Meanwhile,we also designed a 15×15 meta-lens array which arranged the units according to the gradient rise from inside to outside.The size of the array is only 45×45×1.705mm~3and with a gain of 25d B which indicated the metasurface structure achieved high transmission and high gain in the case of small size.To improve the property of MMW radar in long-distance detection,a double helical metamaterial unit composed of two segments of aluminum helix and a dielectric substrate was proposed under the hot spot of chiral metamaterials follows.The lens antenna consisting of the double helix units has a maximum gain of 26d B at 75-79GHz and a half-power beam-width of the antenna is only about 10°which can detect targets over a wider range.Under the premise of low-cost and easy-integration,two kinds of MMW radar antennas proposed in this paper achieved high gain,high transmission and wide-band,which provided a novel way and method for the research and design of vehicle-mounted MMW radar.