Design and analysis of Koch fractal antenna for wireless application

This paper presents a compact Koch fractal patch antenna optimized for wireless applications, employing microstrip feeding and flexible substrates to achieve a novel 10 mm radiating element, one of the smallest fractal designs reported. The Koch fractal geometry, through iterative refinements across 0th to 2nd iterations, enables dual-band and multiband operation, with the 1st iteration achieving a peak impedance bandwidth of 5.4 GHz (3.9–9.3 GHz), significantly enhancing multiband performance for ultra-wideband (UWB) systems such as Bluetooth, wireless local area network (WLAN), and aeronautical radio navigation. Parametric analysis across substrates (polyester, polyethylene, polyamide, FR4) and thickness of 0.762 mm and 1.6 mm evaluates return loss, gain, voltage standing wave ratio (VSWR), and radiation patterns, revealing a radiation efficiency exceeding 85%. The polyester substrate delivers superior performance, with a return loss of −28.07 dB and near-optimal VSWR, establishing a novel benchmark for flexible UWB antennas. These findings offer critical design insights, providing a high-efficiency, scalable solution for advanced wireless communication systems.