Reconfigurable fractal antennas for future wireless applications: A comprehensive review

Abstract

Reconfigurable fractal antenna (RFA) design is always necessary for the continued development of wireless communication systems as the antenna is playing a vital part in device performance. The need for efficient radiators that are compact, low-profile, inexpensive, and low weight has attracted scientists for their research works. As a result, numerous ideas were put forward by the researchers to attempt to resolve these problems by utilizing various kinds of fractal and reconfigurable antennas as well as their combinations. However, it is challenging to have a clear and transparent review of the various works with a large variety of solutions and their uniqueness. The advanced RFA design for wireless applications is reviewed in this study together with its most recent and pertinent counterparts. In Koch RFA, bandwidths enable selective bands spanning 1–6 GHz frequency range. Further, in band RFA design, the overall bandwidth ranges from 1.45 to 4.52 GHz (103%) with low gain; on the other hand, the crescent RFA achieves 5.67 dBi peak gain. Furthermore, in polarization RFA, the ARBWs are 17.61% (2.2–2.62 GHz) and 8.69% (2.91–3.18 GHz). The Hilbert RFA operates at 0.9 and 2.45 GHz with gains of 3.1 and 7 dBi, respectively. This article investigates a comprehensive review of the requirements for RFAs for wireless applications. Furthermore, a comparative study on different reconfigurability with switching techniques, fractal geometries, various RFA design approaches to enhance device performance, and their significance is discussed. Existing research challenges and future directions are also discussed as part of this article.