Design of Millimeter-wave Compact Waveguide Slot Coupled Microstrip Array Antenna

Millimeter-wave microstrip antenna has the advantages of low profile, easy processing and light weight. It is widely used in military and civilian fields. A millimeter-wave microstrip array antenna working in 35Ghz is presented in this paper. A new compact waveguide-slot-patch coupling structure is used in this antenna, which has three functions of coupling, power division and radiation, effectively suppressing the stray radiation of slots, reducing the loss of transmission lines, and then improving the radiation of antennas. Based on this structure, an 2×2 sub array is designed and optimized by monitoring the amplitude and phase of the surface current firstly. And then, an 8×8 series feed uniform distributed planar array is designed. The simulation gain is up to 21.6dB and the radiation efficiency is up to 88.6%. It is higher than the traditional microstrip array antenna. So, it has a broad application prospect.