A Novel Ultrawideband Miniature Vivaldi Antenna With Sawtooth Outer Edges and Inclined Elliptical Slots

A new ultrawideband (UWB) miniaturized Vivaldi antenna with a continuous sawtooth outer edge and two pairs of inclined elliptical slots (SEVA) is proposed in this letter. A step-by-step design method is adopted to design a sawtooth outer edge structure on the Vivaldi antenna (SVA), which improves the antenna gain initially with the uniformly arranged sawtooth structure; then, based on the SVA, two pairs of inclined elliptical slots with inclined angles are designed to extend the lower bandwidth limitation and further improve the gain. The designed SEVA optimizes impedance matching, expands the operating bandwidth, significantly enhances the directivity of the antenna, and addresses the poor low frequency (LF) radiation characteristics of the conventional coplanar Vivaldi antenna (CVA). Within the antenna operating range of (3.2 to 16.8) GHz, the gain is consistently above 5 dB, with a peak gain of 10.4 dB at 10.5 GHz, which is a 3.1 dB improvement over the CVA. Furthermore, the antenna dimensions are only 33 mm × 34 mm. The SEVA is fabricated and tested, with the measured results aligning well with the simulated results, thus confirming the effectiveness of the design.