Abstract: The paper designs a Vivaldi antenna with a gradient period structure in order to improve the gain of the original Vivaldi antenna in the working band. The gradual periodic structure is a metal patch arranged in an equidistant period, and the electromagnetic energy is transmitted to the direction of the vibrator by exciting the vibrator, thereby improving the antenna gain. The simulation results show that the gain of the Vivaldi antenna loaded with structure increases by 2. 1 dB in the range of 6 ~16 GHz. Vivaldi antenna is re-optimized by using a symmetric periodic structure. The S11 parameter has a maximum notch depth of 8. 7 dB and the gain is increased a value of 1. 6 dB in the range of 12 ~14 GHz. Finally, the antenna is physically processed and tested, and the results verify the effectiveness of the design.