Miniaturized Design of Vivaldi Antenna Based on an Improved Nonuniform Slot Profile Method for Ultrawideband Applications

This communication introduces a refined design for the Vivaldi antenna, utilizing a nonuniform slot profile based on the Nonuniform Transmission Lines (NTLs) theory to achieve significant miniaturization suitable for Ultra-Wideband (UWB) applications. The research introduces two models: Model A facilitates direct comparison with the original design, while Model B extends the operational bandwidth through a synergistic optimization of the slotline and the feeding structure. The dimensions of the proposed antennas are reduced from 29.8 mm × 20.26 mm to 28.6 mm × 17.5 mm for Model A and 29.5 mm × 17 mm for Model B, corresponding to size reductions of 17.1% and 16.9%, respectively. Concurrently, the bandwidth is expanded from 2.9–13.55 GHz to 2.83–13.7 GHz for Model A and to 3.12–25.6 GHz for Model B. This novel design approach not only facilitates miniaturization but also enhances the bandwidth and improves impedance matching. The correspondence between the measured results and the simulation predictions substantiates the reliability of this new methodology. Furthermore, this communication introduces an innovative error quantization method that accurately determines the optimal dimensions of the nonuniform slotline, thereby refining the structural design and enhancing the accuracy of the Vivaldi antenna designs.