High gain slot-pair substrate-integrated-waveguide antenna for 77 GHz vehicle collision warning radar

A 77 GHz high gain slot-pair substrate-integrated waveguide (SIW) antenna array has been proposed for automotive radar application. The slot-pair radiation element has been introduced to decrease the guided wavelength, which increases the aperture efficiency. Moreover, the slot-pair element provides the variety to change the antenna performance. Finally, a high gain antenna for forward-looking automotive radar has been fabricated. The measurement gain is 25 dBi and side-lobe level (SLL) is 15 dB, and the aperture efficiency is 62% of the size of 62 mm by 12 mm.