A Corner Truncated Patch Antenna Array for 77GHz Automotive Radar Application

A novel antenna array which is composed of corner truncated patch antennas with wide impedance bandwidth is proposed for 77GHz automotive radar antenna application. In conventional, the corner truncated patch antennas are often used to design circularly polarized antenna. However, in this design the corner truncated patch antennas are applied to design wide bandwidth antenna. The bandwidth of the element is extended because the element can excite two modes which are orthogonal. However, the two orthogonal modes also produce large cross-polarization. To reduce the cross-polarization of the proposed antenna element, four corner truncated antennas are placed symmetrically with a differential feed network. To achieve a high gain, the antenna array is composed of a 8 × 2 corner truncated antenna. The feed network of the antenna array consists of a parallel feed network to achieve a broad bandwidth. Simulations show that the proposed antenna presents an impedance bandwidth of 27% from 70 to 91GHz with a low profile of 0.254mm ( $\lambda_{0}/16$ ) thickness and a peak gain around 16.7dBi at 77GHz. Besides, narrow beam width and low cross-polarization of −45dB are obtained which is meet the demands of the automotive radar antenna.