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e constant evolution of wireless handheld devices together with the apparition of multiple wireless communication systems fosters the antenna community to design new radiating and measurements systems capable of satisfying the market demands. It is an object of the present paper to provide an overview of the evolution that wireless handheld technology has experienced in the last years. In this sense, a description of the evolution of wireless handheld devices, regulations, challenges in today's smartphones, and handset characterization is reviewed. Finally, recent advances in antenna technology for wireless handheld or portable devices are presented.

Fractal geometry has been proven to be useful in several disciplines. In the field of antenna engineering, fractal geometry is useful to design small and multiband antenna and arrays, and high-directive elements. A historic overview of the most significant fractal mathematic pioneers is presented, at the same time showing how the fractal patterns inspired engineers to design antennas.

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A low profile planar antenna, comprising a driven element coupled with one or more parasitic elements is proposed. The design is suitable to be used into a handheld device due to the antenna reduced dimensions (33 × 15 × 1 mm3). To facilitate the integration of other components, such as cameras or speakers, a ground plane area at the right side of the antenna is provided. The study carried out reveals the relevance of the arms location over the performance of the antenna. The theoretic analysis is reinforced using a network model and a parametric study. The coupling between elements controls the behavior of the antenna. In this sense, a weak coupling between the driven element and at least one parasitic element enhances the bandwidth, whereas a multiband behavior is achieved by a tight coupling. Finally, the PCB (Printed Circuit Board) influence has also been analyzed. ©2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 359–364, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24893

Abstract

With the recent advancement and phenomenal progress in the field of wireless communication technology, there is an ever increasing demand for high data rates and improved quality of service for the end users. In recent times various designs of super wideband antennas (SWB) fulfilling diverse objectives have been proposed for modern wireless networks. Design of compact and wideband antenna for high speed, high capacity, and secure wireless communications presents a challenging task for designers of fixed and mobile wireless communication systems. In this paper, a comprehensive review concerning antenna structures and the technologies adopted for design and analysis of SWB antennas for wireless application is reported. Comparative parameters in terms of electrical dimension, bandwidth, Fractional bandwidth (FB) and Bandwidth Dimension Ratio (BDR) are presented which introduces the researchers to the technical challenges in the design of a compact wideband antenna. This paper contributes to present existing novel approaches along with its adequacy in the design techniques. This review exercise will assist the researchers with valuable support for further research and to achieve better impedance matching, wide bandwidth, high gain and good efficiency along with well directive radiation characteristics.INDEX TERMS Bandwidth dimension ratio, compact design, fractal antenna, monopole antenna, super wideband antenna.

A new printed compact structure constructed of six E‐shaped arms arranged in three columns and two rows is proposed and demonstrated as a novel leaky‐wave antenna beam steering from −30° to +15° with respect to broadside direction. This antenna covers the measured frequency bandwidth from 0.93 GHz to 3.65 GHz (approximately 119%, S11 less than10 dB) and the scanned angle moves from backward to forward radiation as the frequency increases. The antenna with overall size of 19.2 mm by 15.2 mm by 1.6 mm (0.059 lambda by 0.047 lambda by 0.004 lambda, where lambda is free space wavelength at 930 MHz), is fabricated on Rogers_RT_Duroid5880 substrate (dielectric constant of 2.2, loss tangent of 0.0009, height of 1.6 mm). The maximum measured gain and efficiency are observed at broadside direction with 8 dBi gain and 90% radiation efficiency. This low‐profile antenna can be flush‐mounted on various structures including vehicles, cellular base stations, or mobile devices. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:215–217, 2016