High-Gain UWB Vivaldi Antenna Loaded With Reconfigurable 3-D Phase Adjusting Unit Lens

In this letter, a flexible three-dimensional (3-D) phase adjusting unit (PAU) lens is designed and loaded in front of a conventional Vivaldi antenna that is able to reconfigure with three typical statuses called planar, inward, and outward by physically bending. The distribution of energy and phase in the aperture of the antenna is therefore altered on demand for the enhancement of antenna gain and the elimination of radiation pattern distortion. The Vivaldi antenna samples loaded with reconfigurable 3-D PAU in the aperture are designed for demonstration, and their performance is compared in the interested frequency range of 6-18 GHz. The measured data show that the antenna gain of the sample with 3-D PAU lens is increased by ~ 1-2.5 dBi within the range of 11-18 GHz. In the higher frequency band of 13-18 GHz, its mainlobe is not split or distorted due to the effective suppression of sidelobe by ~ 1-5.5 dBi. Thus, the practical working bandwidth is significantly extended by 71%, from approximately 6-13 to 6-18 GHz, demonstrating the proposed method improves the antenna gain and stabilizes the radiation pattern of Vivaldi antenna concurrently over a wide frequency band.