Analysis and Design of Millimeter Wave Series-Fed Microstrip Array Antenna

To meet the growing demand for Millimeter Wave antenna performance, we investigated the series-fed microstrip array antenna operating at 77 GHz and analyzed its admittance characteristics using the microstrip transmission line model. A two-dimensional low-sidelobe microstrip array antenna has been designed, which composed of $8 \times 8$-element rectangular patches by combining the form of serial feeding and the microstrip power divider. The simulation results show that the optimized serial feed antenna array can achieve a gain of more than 22.6dB at the center frequency of 77.5GHz. The half-power lobe widths of the E-plane and H-plane are about 14.7° and 11.7°, respectively. By using quarter-wavelength transformer and amplitude weighting, the side lobe level (SLL) of the series-fed array antenna is lower than −17dB. The bandwidth is about 810MHz (VSWR<1.5). This antenna is easy to manufacture, and has the characteristics of low sidelobe, high gain and narrow beam, which meets the design requirements.