Advanced Dual Circularly Polarized Antenna for Automotive Radar Systems

Licentiatavhandling, 2022

Advanced driver assistance systems (ADAS) promise reliable support for collision avoidance and cruise control. The demand for precise target  classification and road surface sensing requires a sensor revolution. In this regard, the automotive radar system is highly expected to collect as much information as possible. Especially, polarimetric radar systems have shown an advantage for sensing and imaging. Automotive polarimetric radar requires an advanced antenna system with high polarimetric capabilities, relatively small size, high efficiency, and low-cost for mass production.
This thesis presents several 77 GHz advanced antenna models for various ranges of automotive polarimetric radar systems. Gap waveguide technology
has been used to design two single-layer dual circular polarized antenna arrays, which are suitable for automotive radar applications. The first antenna
is a dual circularly polarized low profile 8×1 array with wide impedance bandwidth and axial ratio bandwidth (11 %), high port isolation (18.6 dB), and
moderate gain (14.8 dBi). The second design presented is an 18×8 series fed planar array which is designed based on the leaky-wave principle and has
about 3.9 % bandwidth with 27.3 dBi gain. The achieved port isolation is better than 17.5 dB.
The proposed antenna arrays can be easily integrated with the commercial radar chip by using simple microstrip to gap waveguide transition. Therefore a
fully functional polarimetric radar front-end could be designed in the future.