Tattoo Antenna Temporary Transfers Operating On-Skin (TATTOOS)

This paper discusses the development of RFID logo antennas based on the logos of Loughborough University and the University of Kent which can be tattooed directly onto the skin’s surface. Hence, this paper uses aesthetic principles to create functional wearable technology. Simulations of possible designs for the tattoo tags have been carried out to optimize their performance. Prototypes of the tag designs were fabricated and read range measurements with the transfer tattoos on a volunteers arm were carried out to test the performance. Measured Read ranges of approximately 0.5 m have been achieved with the antenna 10 µm from the body

Fully fabric knitted antennas for wearable electronics

The worldwide wearable technology market is expected to exceed $6B by 2016 and wearable antennas will be used by the emergency services, fashion designers, military, athletes and patients. Exploring different methods of fabricating antennas is important especially as user comfort and aesthetics are key considerations in ensuring mainstream acceptance. Previously the authors have examined embroidered antennas using highly conductive threads [Chauraya et al. EuCAP 2012]. Please see this paper for a detailed literature review of wearable antennas. In this paper, we examine knitting as a technique of fabricating antennas. These antennas were fully fabric with a knitted ground plane, a knitted substrate and a knitted patch element. They were fabricated using industrial knitting machinery and hence could potentially be scaled up to mass-manufacture. Four different versions were considered (all had a knitted ground plane and substrate): i) a conducting coated nylon fabric (Nora Dell); ii) a knitted patch with a high fiber density (Sample 1); iii) a knitted patch with a medium fiber density (Sample 2) and iv) a knitted patch with a coarse fiber density (Sample 3). The resulting antennas were extremely flexible and soft to the touch. The return loss results are shown in the figure. All the antennas were fed with a probe feed positioned the same distance from the edge of the patch - the magnitude of the return loss could be improved by finding the optimal feeding point. The S11 and associated bandwidth results of the antennas suggests that the Nora Dell antenna exhibits the smallest losses. The results also indicate that the losses of the knitted antennas improve as the knitted patches became denser. The presentation will include measured radiation patterns, efficiency results and an in-depth analysis of the strengths and weaknesses of this manufacturing technique

Addressing the challenges of fabricating microwave antennas using conductive threads

This paper examines the advantages and challenges of creating microwave patch antennas using conducting threads. The antennas are produced using automated embroidery machinery that could be easily scaled up to mass manufacture. Textile patch antennas are designed that resonate between 2 and 2.7GHz depending on the substrate. Different stitch directions and compositions were considered. Measured gain and efficiency results are included in this paper

Design, realisation and evaluation of a liquid hollow torso phantom appropriate for wearable antenna assessment

This paper examines the design, realization and evaluation of a lightweight and low cost hollow oval cross-section torso phantom appropriate for wearable antenna performance assessment. The phantom consists of an empty inner space (hollow) surrounded by a shell with double plastic walls between which there is a tissue simulating liquid. The phantom’s plastic shell is made of a low loss cast acrylic and the liquid is a commercially available one with properties calibrated for the frequency range of 2 - 6 GHz. The proposed phantom is compared, through simulations, with a full liquid torso phantom and a heterogeneous anthropomorphic voxel phantom. Additionally, the fabricated phantom is compared with human bodies and a homogeneous anthropomorphic solid phantom, through measurements. The phantom performance is tested in terms of electric field distribution of a wearable antenna on its surface and the path loss between two wearable antennas, on either side of the phantom. It is proved that the hollow phantom performance approximates the full liquid phantom when an RF absorbing material is placed in the central hollow region. The phantom performance in terms of S11 wearable antenna measurements is evaluated and found in good agreement with real human bodies in the examined frequency range (2 - 6 GHz). The far field wearable antenna performance of the proposed phantom shows deviation in gain less than 1.5 dB, compared with anthropomorphic phantom

Fabric based frequency selective surfaces using weaving and screen printing

This paper is a postprint of a paper submitted to and accepted for publication in Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library at: http://dx.doi.org/10.1049/el.2013.2314Two examples of fabric based frequency selective surfaces (FSSs) are presented. The FSSs are produced by using screen printing and weaving. Both measured and simulated data are presented showing excellent agreement and performance for the FSSs when compared with the simulated data. The performance of these samples points towards a useful screening technique using fabric hangings and wall coverings in a range of applications where temporary electromagnetic wave ingress or egress needs to be controlled

Design, realisation and evaluation of a liquid hollow torso phantom appropriate for wearable antenna assessment

This paper is a postprint of a paper submitted to and accepted for publication in IET Microwaves, Antennas & Propagation and is subject to Institution of Engineering and Technology Copyright. The copy of record will be available at the IET Digital Library.This paper examines the design, realization and evaluation of a lightweight and low cost hollow oval cross-section torso phantom appropriate for wearable antenna performance assessment. The phantom consists of an empty inner space (hollow) surrounded by a shell with double plastic walls between which there is a tissue simulating liquid. The phantom’s plastic shell is made of a low loss cast acrylic and the liquid is a commercially available one with properties calibrated for the frequency range of 2 - 6 GHz. The proposed phantom is compared, through simulations, with a full liquid torso phantom and a heterogeneous anthropomorphic voxel phantom. Additionally, the fabricated phantom is compared with human bodies and a homogeneous anthropomorphic solid phantom, through measurements. The phantom performance is tested in terms of electric field distribution of a wearable antenna on its surface and the path loss between two wearable antennas, on either side of the phantom. It is proved that the hollow phantom performance approximates the full liquid phantom when an RF absorbing material is placed in the central hollow region. The phantom performance in terms of S11 wearable antenna measurements is evaluated and found in good agreement with real human bodies in the examined frequency range (2 - 6 GHz). The far field wearable antenna performance of the proposed phantom shows deviation in gain less than 1.5 dB, compared with anthropomorphic phantom

Performance and radiation patterns of aesthetic and asymmetric logo-based patch antennas

This article was published in the Journal of Electromagnetic Waves and Applications [© Taylor & Francis] and the definitive version is available at: http://dx.doi.org/10.1080/09205071.2014.893844This paper investigates microstrip patch antennas designed using aesthetic and asymmetrical logo-based shapes. A range of shapes have been considered and analyzed using electromagnetic simulations and measurements. Particular attention has been given to the radiation patterns of these asymmetric antennas

A COMPACT AND LOW-PROFILE TUNABLE LOOP ANTENNA INTEGRATED WITH INDUCTORS

We present a frequency-tunable, compact loop antenna which consists of a transmission line on a ground plane, two shorting posts, and two inductors which are serially connected between the posts and the edge of the transmission line. By properly choosing the inductance of the inductors, the operating frequency of the antenna can be controlled without seriously sacrificing fractional bandwidth. To demonstrate the operating mechanism, the equivalent circuit of this antenna is included. The characteristics of the antenna with various inductors integrated are also investigated. Fabricated antennas show that the operating frequency can be shifted from 2.07 GHz to 1.2 GHz using off-the-shelf inductors. Using two 33-nH inductors achieves an antenna with an electrical size as small as 0.11 lambda x 0.013 lambda x 0.047 lambda. The validity of this antenna is demonstrated by experimental results.X1113sciescopu