UWB, High-Isolation Asymmetric Vivaldi Antenna Array Loaded With Composite Decoupling Structure

In this paper, a composite decoupling structure is proposed to improve the isolation between two Vivaldi antennas. Vivaldi antennas are designed with an asymmetric structure to enhance direct coupling interference between adjacent antennas. On this basis, the Composite decoupling unit which is combination with Middle layer unit and Outer layer unit, the |S21| between two antenna elements is decreased to lower than -20.95 dB from 2.07-7.5 GHz, and the maximum isolation is improved to 41.78 dB, the coupling energy from the antenna sides can be effective absorbed. The proposed antenna is designed, fabricated and tested, the measurement results are good agree with the simulation results, the maximum gain reduction does not exceed 1.7 dBi, and the radiation patterns also maintain good end-fire characteristics. These characteristics make the proposed structure have application potential in mobile communication, shallow ground penetrating radar, etc.