The combination of fractal geometry with electromagnetic theory opens an interesting window for research to find new antenna designs and applications. Fractal technology applications can be divided into six main groups: (1) multifrequency antenna elements, frequency‐selective surfaces, and arrays; (2) electrically small antennas; (3) high‐directivity radiating elements; (4) low‐sidelobe arrays; (5) undersampled arrays; and (6) fast computational methods. This article reviews most of the work done in the fractal technology field covering the last six fields.

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Abstract-The properties of the Koch island fractal boundary microstrip patch antenna are presented. The behavior at the fundamental mode and the existence of high-order modes that exhibit localized current density distributions is discussed. The main features are the size reduction of the patch resonating at the fundamental frequency when compared to Euclidean-shaped patches, and the application of localized modes in designing microstrip patch antennas with directive patterns.

A small H-shaped microstrip patch antenna (MPA) with enhanced bandwidth is presented. The H-shaped antenna is first studied by a transmission line model and then is fully analyzed with a MoM code. A stacked patch configuration is proposed to increase the narrow bandwidth, radiation efficiency and directivity. The stacked H-shaped MPA is studied using Chu's fundamental limit for electrically small antennas.Index Terms-H-shaped antennas, limit of Chu, microstrip antennas, small antennas, stacked patches.