The growing demand for antennas with enhanced gain and bandwidth (BW) that are suitable for the applications of modern communication systems like Vehicle-to-Everything (V2X) has invoked the use of a composite right/left-hand (CRLH) array. However, these structures suffer from drawbacks such as increased antenna size, side lobe level (SLL), and back lobe level (BLL) due to the total internal reflection phenomenon. This research aims to design a compact antenna system that minimizes SLL and BLL with enhanced gain and BW. In this study, CRLH array based on 14-unit cells of Hilbert and Minkowski fractal structures was integrated with a Vivaldi antenna mounted on a Rogers RT5880 substrate with an area of \(21.87\times 90.5~\text {mm}^2\) . A hexagonal reflector is placed at the bottom of the antenna to reduce SLL and BLL to -10.6 dB and -2.6 dB, respectively. The maximum achieved gain is 14.5 dBi at 15.4 GHz, with an overall BW of 2.8 GHz, spanning two sub-bands, 14.8–16 GHz and 16.4–18 GHz. The Bit Error Rate (BER) and Channel Capacity (CC) are evaluated using a MATLAB framework with the Signal-to-Noise Ratio (SNR). The results demonstrate a 91.38% decrease in BER compared to the antenna without the reflector and an 11.53% improvement in CC under the same conditions. An analysis based on circuit theory is adopted to evaluate the performance of the proposed CRLH unit cell array through S-parameter analysis in magnitude and phase spectra. Such analysis is performed based on the circuit elements of the proposed CRLH array, which are obtained from an Artificial Neural Network (ANN) schematic. Finally, the proposed antenna is fabricated to demonstrate excellent agreement between the measured and simulated data, providing a reliable option for high-frequency communication systems.
