Bio-Inspired Wearable Antennas

Abstract

Additional information available at the chapter Abstract Due to the recent miniaturization of wireless devices, the use of wearable antennasis steadily increasing. A wearable antenna is intended to be a part of the clothing used for communication purposes. In this way, a lower visual cost may be achieved. Recently, biologically inspired design, a kind of design by cross-domain analogy is a promising paradigm for innovation as well as low visual cost. The shapes of the plants are structures optimized by nature with the primary goal of light energy capture, transforming it into chemical energy. In this case, they have similar behavior to that of parabolic reflectors; this enables microwave engineers design innovative antennas using bio-inspired concepts. One of the advantages of using bio-inspired plant shapes is the design of antennas with great perimeters in compact structures. Thus, we have small antennas operating in low frequencies. This chapter presents the recent development in bio-inspired wearable antennas, easily integrated to the clothes and accessories used by the body, built in denim, low-cost flexible dielectric, and polyamide flexible dielectric, that is flexible with high resistance to twists and temperatures, for wireless body area network (WBAN) applications, operating in cellular mobile (2G, 3G, and 4G) and wireless local area network (2.4 and 5 GHz) protocols. polyamide). Designed antennas were analyzed by simulation and by measurement in implemented prototypes. The proposed bio-inspiration results in more compact antennas by the reduction of the antennas radiating element. However, compared to Euclidean shapes, two side effects were observed a reduction of the gain and an increase of the current density. On the other hand, the bio-inspired antennas present a higher concentration of the surface current and the decrease of gain can be prevented using leaf arrays with esthetic appeal. The gain can be improved by using thicker substrates and the current density can be regulated using plant shapes with flat geometries or the least sharp possible. These characteristics open a large research field for wearable embedded antennas.