Dielectric loaded directive Vivaldi antenna considering dispersion in near and far field

Abstract

A “V” slot dielectric loaded antipodal Vivaldi antenna is proposed in this article, which provides significant improvement for directivity, front to back lobe ratio and low side lobe level over the operating frequency band from 1.76 GHz to 10 GHz. Initially, the 35° upward tilted parallel slots are placed along the outer curvy conductor edges of the antenna to maintain the desired radiation performances and impedance matching. Thereafter the V slot extended dielectric slab is integrated with this design for the improvement of radiation performances and pulse spreading effect while maintaining high directivity. The antenna prototype is fabricated and tested which shows the return loss is below the 10 dB, maximum directivity is achieved at 10 GHz which is 17.5 dBi and front-to-back lobe level ratio is 29.2 dB, almost triple as compare to conventional Vivaldi antenna at 9 GHz. The measured results depicts that the highest main lobe squint angle is 2.7° at 6 GHz. In addition to this, the measured system fidelity factor (SFF) is 0.86 and 0.91 at near and far field respectively which confirms that the V slot actually reduces the pulse spreading and dispersion effect while maintaining the high directivity.