Design, Fabrication, and Testing of Flexible Antennas

Abstract

Additional information is available at the end of the chapter http://dx.doi.org/10.5772/50841 . IntroductionRecent years have witnessed a great deal of interest from both academia and industry in the field of flexible electronics. In fact, this research topic tops the pyramid of research priorities requested by many national research agencies.According to market analysis, the revenue of flexible electronics is estimated to be billion USD in and over billion USD in [ ].Their light weight, low-cost manufacturing, ease of fabrication, and the availability of inexpensive flexible substrates i.e. papers, textiles, and plastics make flexible electronics an appealing candidate for the next generation of consumer electronics [ ]. Moreover, recent developments in miniaturized and flexible energy storage and self-powered wireless components paved the road for the commercialization of such systems [ ].Consistently, flexible electronic systems require the integration of flexible antennas operating in specific frequency bands to provide wireless connectivity which is highly demanded by today's information oriented society.Needless to say, the efficiency of these systems primarily depends on the characteristics of the integrated antenna. The nature of flexible wireless technologies requires the integration of flexible, light weight, compact, and low profile antennas. At the same time, these antennas should be mechanically robust, efficient with a reasonably wide bandwidth and desirable radiation characteristics.This chapter deals with the design, numerical simulation, fabrication process and methods, flexibility tests, and measurements of flexible antennas. As a benchmark, a flexible, compact, and low profile . µm printed monopole antenna intended for the ISM band applications at . GHz is presented and discussed in details. The antenna is based on a Kapton Polyi-

Wearable Textile Antennas with High Body-Antenna Isolation: Design, Fabrication, and Characterization Aspects

“…The design of wearable antennas for body-centric communications is discussed in [2][3][4][5][6][7][8], and the most important requirements are summarized Table 1.…”

“…Hence, flexible, thinner, and low-cost materials should be chosen to make the antenna conformable to the person wearing the wearable device and to meet mechanical and manufacturing requirements. Materials like polymers [3,13], non-conductive fabrics [4], paper [14], and flex film [5,6] have been used as the substrates in the existing wearable antennas [3,15]. The choice of material for the antenna's substrate is a critical factor in the performance of the antenna and is examined in depth in Section 3.…”

“…After that, a prototype of the optimized design of the wearable antenna can be fabricated using the methods for fabrication of flexible and wearable antennas presented in [5,8,13].…”

“…In passive antenna measurements, the prototype is connected to the measuring equipment (a network analyzer, signal generator, receiver, or spectrum analyzer) using an external coaxial cable. Moreover, full verification of the antenna design requires more extensive testing, such as flexibility tests (described in [4,5]) and tests which represent the behavior of the antenna in real working conditions (also called active antenna measurements). In these measurements, a wearable device simulator (or a radio communication test module) is used to set up a connection to the antenna under test, which is embedded into a complete operating wearable device (or connected to a radio communication module) to reproduce real-world behavior.…”

“…However, because the wearable antenna operates in a specific environment (on or near to the human body), the effects due to lossy body tissues (as impedance mismatching, radiation-pattern distortion, radiation efficiency reduction) make the design of a wearable antenna a difficult task. Therefore, care is needed in designing antennas for wearable devices [4,5].…”