Design of an Antipode-Type Vivaldi High Gain Antenna

In order to improve the radiation gain of the traditional Vivaldi antenna in low frequency band to meet the needs of microwave detection of brain activity, an antipode-type Vivaldi antenna with dimension of 100 mm× 120 mm× 2 mm is designed. The radiation characteristics of the antenna is improved by adopting the method of loading a circular reflector on the ground layer,while the size of the original antenna is not changed. The results show that the VSWR of the antenna in the 1-3 GHz band is lower than 2, the gain is higher than 4 dB which is increased by a maximum of 3 dB compared to the gain without the reflector in the frequency band. The antipode-type Vivaldi antenna is fabricated and measured, the measured results agree well with the simulated, so that the antenna can be applied to human brain activity detection and other fields.