Abstract: To address the challenges posed by the limited gain and significant backlobe radiation of conventional Vivaldi antennas, a novel miniaturized Vivaldi antenna with sawtooth-shaped outer edges is meticulously designed. The sawtooth structure effectively improves the current distribution on the antenna surface, concentrating the current near the slot line, significantly enhancing antenna gain and improving the front-to-back ratio. Within the frequency range of 4.9 GHz to 16.6 GHz covered by this antenna, the maximum gain is increased by 2.3 dB, reaching a peak gain of 9.7 dB. Particularly, the antenna gain remains above 5 dB within the range of 6.2 GHz to 15.8 GHz. The peak front-to-back ratio reaches 24.5 dB, effectively reducing the size of the antenna′s backlobe and greatly enhancing its directivity. The antenna is designed to be compact, with dimensions of only 34 mm × 33 mm. The antenna is being fabricated and tested, and the measured results show a good agreement with the simulated results. It holds broad application prospects in fields such as ultra-wideband wireless communication, radar detection, electronic warfare, and remote sensing.