ADVANCED DESIGN AND EXPERIMENTAL PERFORMANCE ANALYSIS OF A HEXAGONAL FRACTAL ANTENNA ARRAY (HFAA) AT NASA JET PROPULSION LABORATORY FOR HIGH-EFFICIENCY 5G/6G WIRELESS COMMUNICATION SYSTEMS

Abstract

The rapid evolution of fifth- and sixth-generation (5G/6G) wireless communication systems has intensified the demand for compact, high-efficiency, and wideband antenna architectures capable of supporting ultra-high data rates, massive connectivity, and low-latency transmission. However, achieving broad impedance bandwidth, high gain, radiation stability, and structural compactness simultaneously remains a critical engineering challenge. This paper presents the advanced design, optimization, fabrication, and experimental performance evaluation of a Hexagonal Fractal Antenna Array (HFAA) tailored for next-generation wireless communication platforms. The proposed array integrates a self-similar hexagonal fractal radiator geometry to exploit multi-scale current distribution and space-filling characteristics, thereby enhancing bandwidth and radiation efficiency without increasing the physical footprint. A full-wave electromagnetic simulation framework was employed to optimize key design parameters, including fractal iteration order, inter-element spacing, feed network configuration, and ground plane dimensions. The optimized HFAA prototype was fabricated on a low-loss dielectric substrate and experimentally characterized using a calibrated vector network analyzer and anechoic chamber measurement setup. Experimental results demonstrate an extended impedance bandwidth satisfying |S11| ≤ −10 dB across the targeted 5G/6G frequency range, along with a peak realized gain exceeding conventional non-fractal array counterparts of comparable size. The array exhibits stable radiation patterns, low cross-polarization levels, improved front-to-back ratio, and high radiation efficiency across the operating band. Compared with traditional patch array configurations, the proposed fractal array achieves enhanced multi-resonant behavior and improved spectral utilization due to its geometrically induced current path elongation and electromagnetic coupling optimization. Furthermore, the hexagonal topology enables symmetrical field distribution and improved array scalability, making it suitable for beamforming and high-density integration scenarios. The results validate that the HFAA architecture provides a promising solution for compact base stations, small cells, and advanced wireless terminals operating in sub-6 GHz and emerging mmWave bands. The proposed design framework establishes a scalable and manufacturable pathway toward high-performance fractal antenna arrays for future 6G-enabled intelligent communication infrastructures.