Gap Waveguide Slot Array Antenna for Automotive Applications at E-Band

High standards for safety and comfort in the modern vehicles require high precision driving assistance systems. Automotive radars play a key role because they operate also in adverse lighting and climate conditions. Automotive radars operating at mmWave frequencies (76-81 GHz) are particularly attractive because of the small sizes and wide bandwidth. Microstrip patch array antennas are the common solution, however, high dielectric losses degrade the radar's performance. To remove dielectric losses, waveguide slot arrays can be used, but at mmWaves it is hard to ensure a good electrical contact between split-blocks. Gapwaveguide technology solves this issue and the performance and robustness has been already demonstrated in different application at these frequencies. Here, we present a high gain ridge gap waveguide slot array antenna for 77 GHz automotive radar. Its narrow width (half of wavelength) allows the proposed antenna to be used in a compact array configuration to implement a bi-static radar with multiple receivers and transmitters.