Hybrid Thin Film Antenna for Automotive Radar at 79 GHz

A novel hybrid approach to designing multilayer antennas for automotive radar using a thin single layer printed circuit board and multilayer thin films is presented in this paper. A new substrate integrated waveguide (SIW) slot fed stacked grid antenna element is designed using this approach. The flexibility of this approach in designing antenna arrays is shown by integrating the same antenna element with three different feed networks based on SIW, grounded coplanar waveguide (GCPW), and microstrip (MS) transmission lines. The antenna is designed to operate in the frequency band between 77 and 81 GHz for automotive radar. Measurement results on 1 × 4 arrays show an impedance matching bandwidth and a realized gain of 7.8% (76.3-82.5 GHz) and 9.2 dBi, respectively, for SIW feed antenna, 11.3% (76.3-85.5 GHz) and 10.7 dBi, respectively, for GCPW feed antenna, and 11.3% (75.7-84.8 GHz) and 12.1 dBi, respectively, for MS feed antennas. The proposed antenna can be used for medium- and short-range automotive radar applications.