Double metamaterial layers covered antipodal Vivaldi antenna

In this article, metamaterial with composite structure is presented to improve the radiation properties of antipodal Vivaldi antenna (AVA). Metamaterial layers, which have a high permittivity than substrate, are used to direct the electromagnetic waves radiated from the sides of the AVA to the end-fire direction in the frequency band of 1-8 GHz. On this basis, the proposed antenna can achieve a high gain in the whole operating band, and the maximum gain is 18.24 dBi at 7 GHz. At the same time, a narrower half-power beamwidth (HPBW) is obtained both on H-planes and E-planes. Compared with the simulation results, the measurements show a better agreement with them. Thanks to these properties, this antenna has a potential in ground penetrating radar, UAV countermeasures system and other broadband wireless systems like these.