Research on Factors Affecting Sidelobe Level of Millimeter Wave Microstrip Array Antenna

In this paper, 77GHz vehicle-borne anti-collision radar antenna is taken as an example to study and analyze the influence factors of millimeter-wave microstrip array antenna sidelobe level. The proposed antenna includes waveguide microstrip conversion, microstrip transmission line, and 10-element unequal amplitude microstrip array antenna. In order to reduce the sidelobe level (SLL), the surface current and the space electric field of the microstrip transmission line are analyzed. The SLL of the antenna is effectively reduced by changing the structure of the microstrip transmission line. When the conventional microstrip transmission line is used, the E-plane SLL of the antenna is -11.43dB. With the improved transmission line form, the SLL and gain are -19.41 dB and 14.43dB, with are increased by 8dB and 0.6dB, respectively.