Enhanced Radiation Characteristics for Vivaldi Antenna Using Spoof Surface Plasmon Polaritons

The traditional Vivaldi antenna is well known for its ultrawide bandwidth, but low gain. To enhance the radiation characteristics, we propose a new method by adding an additional structure that supports spoof surface plasmon polaritons (SSPP) as the parasitic element. The proposed patch has an enhanced gain over whole frequency band without deteriorating the bandwidth. The Sommerfeld–Zenneck wave mode and slow-wave mode benefit the gain and realize better directivity. The maximum gain could improve as high as 5 dBi. Several measured results are successfully confirmed with simulations, which demonstrate the higher directivity in the endfire direction. This design method provides a new method to improve the radiation characteristics for Vivaldi antenna.