A novel antipodal Vivaldi antenna for ultra-wideband far-field detection

A novel antipodal Vivaldi antenna with enhanced gain and directivity is proposed. The substrate of the antenna is innovated to a combination of circular-shaped and rectangular-shaped. To enhance the gain, a fan-shaped expansion structure, serving as a dielectric lens, is loaded along the opening of the patch. Besides, to enhance the directivity, several directors are loaded in the vertical direction of the substrate. The loaded directors use some other dielectric substrates as carriers and exhibit spatial anisotropic symmetry. The proposed antenna was simulated on CST 2020 software platform and measured by using a vector network analyzer in the chamber. The results show that the proposed antenna has a reflection coefficient below -12 dB in the frequency range of 3 to 10 GHz. Based on the scalloped expansion structure and the vertical directors, the peak gain is higher than 8 dBi after 6 GHz, and the directivity is improved. To further demonstrate the detection capability, a far-field detection experiment is designed by using CST 2020. Meanwhile, a far-field experiment in the laboratory is designed to analyze the detection capability of the fabricated antennas. The obtained results demonstrate that the antenna can be well used in ultra-wideband far-field detection applications.