Dual-Circularly Polarized Antenna Array for Automotive Radar at 77 GHz based on SISL Topology

A substrate integrated suspended line (SISL) architecture based compact dual-circularly polarized antenna is presented. The antenna has a wide impedance and polarization bandwidth, covering 76-81 GHz. The antenna array is created using sequentially rotated elements. The proposed 4-layer antenna has low profile among the available literature with a thickness of 0.15λ while the overall size is 20 mm × 10 mm × 0.611 mm. The port isolation is greater than 35 dB while the cross-polar discrimination is less than -22 dB. The axial ratio is less than 2 dB over the entire band. The above antenna has the potential application as polarimetric radar in automotive industry.