Horn and lens antenna array with chevron‐shaped prism for 77‐GHz automotive radar with dual‐range sensing and a dual field of view

Abstract

A transmitter antenna array composed of two horn and lens antennas sharing a novel chevron‐shaped prism and one horn and lens antenna without such a prism has been investigated for 77‐GHz‐band automotive radar with dual‐range sensing and a dual field‐of‐view (FOV). The horn and lens antenna without the prism is directed at boresight to produce a radiation pattern with a narrow FOV for long‐range detection. The portions of the prism output surface corresponding to the two antennas that share the prism are angled in opposite directions to tilt their radiation patterns to the left and right and thereby provide a wide FOV in azimuth for middle‐range detection. The prism created a smooth radiation pattern in the major lobe when the tilt angle was large enough to achieve an azimuth FOV of more than ±35°. A fabricated transmitter antenna array achieved a gain of 21.5 dBi and a half‐power beam width of 22° at boresight for long‐range detection and one of more than 15.5 dBi within azimuth angles of ±35° for middle‐range detection at 76.5 GHz. This antenna array for long‐ and middle‐range detection had reflection coefficients (S11) of less than −14 and −17 dB, respectively, from 76 to 77 GHz. The antenna array thus produces the beams required for dual‐range dual‐FOV radar. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.