Coplanar Vivaldi Antenna with Koch Fractal Lens for L and S-band application

Vivaldi Antenna is a planar antenna that has a superiority of wide bandwidth, high gain, and directional radiation pattern. In this study, we compared the return loss and radiation pattern performance of four Coplanar Vivaldi Antenna that operated in the frequency L and S-band (0.5-6 GHz). Those antennas are Regular Coplanar Vivaldi Antenna (RCVA), Exponential Slot Edge Coplanar-Vivaldi Antenna (ESECVA), Exponential Slot Edge Coplanar-Vivaldi Antenna with Regular Lens (ESECVA-RL), and Exponential Slot Edge Coplanar-Vivaldi Antenna with Koch Fractal. Lens (ESECVAKFL). From the simulation result, the directivity performance from the lowest to the highest was obtained of 6.37 dBi, 9.19dBi, 9.74 dBi, and 11. 4SdBi by RCVA, ESECVA, ESECVA-RL, and ESECVA-KFL respectively at a frequency of 2.5 GHz. The provision of corrugated and lens structures can increase the radiation pattern performance of the antenna. It is found that ESECVA-KFL obtains the best side lobe level (SLL) performance at a frequency 1.5 GHz of -15dB. However the SLL for ESECVA, ESECVA-RL, and RCVA are -12.95dB, - 11.99dB, and -4.97dB respectively. It can be concluded that the ESECVA-KFL structure can improve the performance of the Vivaldi antenna radiation pattern.