Design of a fractal inspired antipodal vivaldi antenna with enhanced radiation characteristics for wideband applications

A novel fractal inspired antipodal Vivaldi antenna is proposed for wideband applications. A step‐by‐step procedure has been employed to design and optimise the performance of the proposed antenna. First, a conventional antipodal Vivaldi antenna (CAVA) is designed as a reference antenna and then a Koch fractal‐shaped parasitic lens is introduced in the CAVA. Finally, a fractal‐shaped dielectric lens has been added as an extension of the antenna substrate. The presence of parasitic fractal lens in the flare aperture and fractal dielectric lens enhances the antenna bandwidth and also improves field coupling between the antenna arms and produces stronger radiation in the end fire direction which in turn increases the gain and directivity of the antenna. The optimised antenna is fabricated and tested showing| S 11 | below −10 dB from 4.2–42 GHz band. The dimension of the proposed antenna is 186 × 66 × 1.524 mm 3 . Results show that |S 11 | characteristics and other parameters are in good agreement with the simulation counterpart.