Metamaterial lenses for monostatic and bistatic 77 GHz radar systems

Metamaterial lenses are appealing thin alternatives to conventional dielectric lenses. In this contribution we describe their design and application in two exemplary 77 GHz automotive radar sensors operating in monostatic and bistatic modes. The frontends are built around commercially available MMICs and small feed antennas are used in coordination with the six-layer printed circuit board-based realizations of metamaterial lenses. The design follows the principles of dielectric lenses, while the required local phase shift is obtained from a set of metasurface bandpasses. Their design uses a novel interpolation procedure to extract layout parameters for a given phase shift. Despite the small structural sizes due to the high frequency, the fabricated frequency-selective surfaces show very good performance in the required frequency range. Verification measurements were conducted on single bandpasses as well as on metamaterial lenses mounted on the radar frontend. The results agree very well with the simulation and confirm the applicability of thin lenses operating at mm-wave frequencies for automotive radar applications.

Automated summary

This article describes the design and application of two metamaterial lenses in 77 GHz automotive radar sensors as thin alternatives to conventional dielectric lenses. The frontends utilize commercially available MMICs and small feed antennas in conjunction with six-layer printed circuit board-based metamaterial lenses. The design follows the principles of dielectric lenses, with the required local phase shift obtained from a set of metasurface bandpasses. Despite their small structural sizes, the fabricated frequency-selective surfaces show excellent performance in the required frequency range. Verification measurements on single-bandpasses and metamaterial lenses confirm their applicability for automotive radar applications at mm-wave frequencies.