Wideband Koch Fractal Technique for Intelligent Reflecting Surface Application
DOI:
https://doi.org/10.14500/aro.12928Keywords:
Fractal geometry, Intelligent reflecting surface, Koch fractal, Metasurface, Reflection phase, Wideband metasurface, X-bandAbstract
This paper presents a wideband X-band IRS based on a novel combined inward–outward Koch fractal metasurface. The proposed unit cell integrates inward and outward Koch fractal geometries to increase the effective electrical current path and support multiple resonant modes, thereby enhancing the reflection bandwidth while maintaining a compact single-layer structure. A 300 × 300 mm² IRS prototype was designed, fabricated, and experimentally validated. Simulation results demonstrate a reflection phase bandwidth of 2.40 GHz (8.95–11.35 GHz), while measurements confirm a bandwidth of 2.25 GHz (8.90–11.15 GHz), corresponding to a fractional bandwidth of 22.44%. The measured reflection magnitude and phase responses are in good agreement with the simulated results. System-level experiments conducted in a non-line-of-sight environment further demonstrate that the proposed IRS improves the received signal strength by more than 15 dB compared with the case without an IRS, confirming its capability to redirect electromagnetic waves and enhance wireless coverage effectively. The combination of wideband performance, compact single-layer construction, and experimentally verified signal enhancement demonstrates the potential of the proposed combined Koch fractal IRS for next-generation intelligent wireless communication systems.
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Copyright (c) 2025 Nur S. Mohd Yaziz, Mohamad Kamal A. Rahim, Farid Zubir, Salah I. Yahya, Noor Asmawati Samsuri, Taufiqqurrachman
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Accepted 2026-08-16
Published 2025-09-18
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