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.

An improved gain and directivity design of an antipodal Vivaldi antenna for ultra‐wideband detection

“…The proposed antenna achieves a larger bandwidth with comparable dimensions to de Oliveira et al 9 and Gao et al 34 and the slots designed in this paper does not significantly decrease the gain compared to. 9 Besides, although the antennas in Karmakar et al 23 and Ghosh et al 26 can also achieve large bandwidth and high gain, they are larger than that the proposed antenna, and their lenses are more complex compared to that in this paper. In addition, the directors in this paper can optimize the directivity without negatively affecting the bandwidth compared to the metamaterials in Binzlekar et al, 37 and the director arrays do not increase the antenna size and structural complexity compared to Guo et al 43 and Binzlekar et al 37 In summary, the proposed antenna is superior in structure.…”

“…[23][24][25] However, this kind of lens was not favorable for the design. The dielectric lenses in Ghosh et al 26 and Tangwachirapan et al 27 were simple, they were large in size, which is not conducive to the miniaturization of the antenna. The tooth-shaped dielectric lens in Asok and Dey 28 was simple and in a suitable size, but the gain enhancement in the highfrequency band was not significant.…”

High gain antipodal Vivaldi antenna with novel V‐shaped air‐slot

“…Due to its ultra‐wideband nature, the electrical radiating aperture becomes much larger than the operating wavelength when frequency becomes higher, therefore the main lobe will split and the side lobe level will arise according to the structure of the tapered opening slot. This shortcoming limits the use of Vivaldi antenna in many applications, such as radio astronomy and pulse communication systems 14 …”