A compact hexagonal Sierpinski fractal antenna for super wideband applications is presented. It consists of hexagonal radiation patch with two iterations of Sierpinski square slots and coplanar waveguide feeding. An impedance bandwidth of 3.4–37.4 GHz is achieved. The achieved bandwidth ratio is 11:1. Desirable radiation performance characteristics including relatively stable and omni-directional radiation patterns are obtained over this range. A good agreement is achieved between the simulated and experimental results. The designed antenna has advantages of wider bandwidth and miniaturised size over the previously reported structures.

CPW-fed hexagonal Sierpinski super wideband fractal antenna

A compact textile ultra-wideband (UWB) antenna with an electrical dimension of 0.24λo × 0.24λo × 0.009λo with microstrip line feed at lower edge and a frequency of operation of 2.96 GHz is proposed for UWB application. The analytical investigation using circuit theory concepts and the cavity model of the antenna is presented to validate the design. The main contribution of this paper is to propose a wearable antenna with wide impedance bandwidth of 118.68 % (2.96-11.6 GHz) applicable for UWB range of 3.1 to 10.6 GHz. The results present a maximum gain of 5.47 dBi at 7.3 GHz frequency. Moreover, this antenna exhibits Omni and quasi-Omni radiation patterns at various frequencies (4 GHz, 7 GHz and 10 GHz) for short-distance communication. The cutting notch and slot on the patch, and its effect on the antenna impedance to increase performance through current distribution is also presented. The time-domain characteristic of the proposed antenna is also discussed for the analysis of the pulse distortion phenomena. A constant group delay less than 1 ns is obtained over the entire operating impedance bandwidth (2.96-11.6 GHz) of the textile antenna in both situations, i.e., side by side and front to front. Linear phase consideration is also presented for both situations, as well as configurations of reception and transmission. An assessment of the effects of bending and humidity has been demonstrated by placing the antenna on the human body. The specific absorption rate (SAR) value was tested to show the radiation effect on the human body, and it was found that its impact on the human body SAR value is 1.68 W/kg, which indicates the safer limit to avoid radiation effects. Therefore, the proposed method is promising for telemedicine and mobile health systems.

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Wireless Body Area Networks: UWB Wearable Textile Antenna for Telemedicine and Mobile Health Systems

We present a detailed study of a very large band planar circular asymmetrical dipole antenna, fed by a microstrip, for the purpose of covering most of the common communication channels with one solution. The study has been performed on two planar substrates having different dielectric permittivities. The prototype on the substrate with lower permittivity shows much larger bandwidth, and it has been realized and fully characterized, in terms of impedance matching and radiation properties. Its measured band ratio is 21.9:1. The comparison with other super-wideband (SWB) antennas of similar type, with more complex design and therefore required optimization, shows that this prototype has very appealing features of very large absolute bandwidth and band ratio, and a compact size.

Study on Super-Wideband Planar Asymmetrical Dipole Antennas of Circular Shape

A novel broadband design of planar arc-shaped monopole antenna with a rectangular parasitic patch for UWB system is proposed. With the use of rectangular parasitic patch, multi resonant modes are excited to meet the specifications of UWB system. Moreover, the obtained impedance bandwidth across the operating band can reach about 10.25 GHz. The measured peak gains and radiation efficiencies are about 1.2-5.3 dBi and 85-91% across the operating band, respectively, with nearly omni-directional pattern in the XY-plane.

Planar Broadband Arc-Shaped Monopole Antenna for UWB System

A coplanar waveguide (CPW)-fed octagonal super-wideband fractal antenna is presented. It comprises four iterations of an octagonal slot-loaded octagonal radiating patch, CPW feedline, and modified ground plane loaded with a pair of rectangular notches. An impedance bandwidth of 3.8–68 GHz (179%) – i.e. a17.89:1 ratio bandwidth – is achieved. Desirable radiation performance characteristics, including relatively stable and omnidirectional radiation patterns, are obtained over this range. The experimental and simulation results are found to be in good agreement. The designed antenna has the advantages of wider bandwidth and miniaturised size over the previously reported structures.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-map.2016.0110

CPW-fed octagonal super-wideband fractal antenna with defected ground structure

In this article, we present a novel circular disc antenna for current and future ultrawideband (UWB) applications. The proposed antenna has a small size of 30 mm × 35 mm, a simple geometry, and the excitation is launched through a 50-Ω microstrip feed line. The impedance matching of the proposed antenna is improved by introducing a second microstrip line between the feed line and the circular patch. A prototype of the proposed antenna has been fabricated and its performances are measured. The obtained results show that the proposed antenna operates on UWB frequency range from 2.7 to 28.8 GHz. Measured radiation patterns and simulated gain and radiation efficiency of the proposed antenna are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1130–1133, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24261

Fransisco Falcone

Papers

A novel compact printed circular antenna for very ultrawideband applications