Design of shorted parasitic rhombic array antenna for 24 GHz rear and side detection system

A novel microstrip patch antenna is proposed for automotive application. The antenna design has been investigated through both the parametric study and the demonstration of surface currents on the antenna structure. The surface currents related to the co-polarisation increased, and those related to the cross-polarisation is reduced by attaching shorted parasitic element. The four types of single antenna are designed to compare of gain and cross-polarisation level. The cross-polarisation level of proposed antenna has been reduced by 5.9 dB compared with the rhombic antenna. The rhombic array antenna and proposed array antenna were fabricated and tested for input reflection coefficient and radiation performance. The measured and simulated results have been presented and discussed.