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Multiple Input Multiple Output (MIMO) antennas have shown tremendous scope for increased capacity in wireless communication systems and are investigated for on-body networks in this work. A multi-antenna system based on truncated semi-elliptical patch antennas is presented and its characteristics evaluated. These patches are placed orthogonal to each other for good spatial and polarization diversity. Moreover, Artificial Magnetic Conductor (AMC) structures are used in the design to provide high isolation. The AMC-backed MIMO antenna provides 14.4% bandwidth and 10.6 dB isolation improvement, compared to the antenna without AMC. Besides, the channel capacity is also increased when AMC is integrated with the antenna. The diversity performance of the designed MIMO antenna is also evaluated in terms of envelope correlation coefficient and capacity loss for the lossy array. The proposed antenna offers spatial, polarization, pattern diversity, and good stability over the human body with improved channel capacity. [ABSTRACT FROM AUTHOR]

In this paper, the influence of user mobility and on-body antenna placement on system loss in body-to-body communications in indoor and outdoor environments and different mobility scenarios is studied, based on system loss measurements at 2.45 GHz. The novelty of this work lies on the proposal of a classification model to characterise the effect of user mobility and path visibility on system loss, allowing to identify the best set of on-body antenna placements. To quantify the influence of visibility and mobility on the average system loss, a combined score is proposed, allowing to map system loss onto the degree of visibility and mobility that depends on the scenario being considered and on on-body antenna placements. Overall, a good agreement is observed between the proposed classification model and the average measured values of system loss, with the higher values of combined scores being associated with lower values of systems loss. For the cases under study, the average values of system loss are 61.6 dB for the cases of the antennas being positioned only on the front of the body and/or the head, and 64.5 dB if at least one of the antennas is placed on an arm.

The design and development of a small-sized, high gain ultra wide band (UWB) antenna based on different substrate materials are presented for on body wireless body area network (WBAN) applications. In the present scenario, on-body wearable antennas wave propagation and radiation pattern characteristics have been rigorously explored for study along with the growth of wireless body area networks. The major focus of the presented work is to perform comparative analysis of different substrate materials on performance of a novel, small sized, high gain UWB antenna design suitable for on body WBAN applications. The comparative investigation of the effect of different substrates materials i.e. FR4, Jeans, Rubber, Fleece, Polyester and Rogers RT 5880 on the designed antenna performance for has been performed. The FR4 substrate material found to optimum for proposed UWB antenna that has an overall measurement of 30 mm × 35 mm × 1.2 mm, possesses a large impedance bandwidth of 119.3%, and exhibits high gain and directivity. The peak measured gain and directivity are realized as 6.0 dB and 6.739 dBi respectively at 11.1 GHz. The performance parameters results of designed and fabricated antenna have been investigated and found to be in good compliance. The simulation and evaluation outcomes of the fabricated antenna demonstrate the suitability of the presented FR4 based antenna for WBAN utilization to be operable for communication in the UWB band. [ABSTRACT FROM AUTHOR]

Wireless Body Area Network (WBAN) requires only a minimum amount of drive procedure with small array message and wide volume is obtainable by Ultra-Wide Band Technology. The humanoid physique presence carries tremendous difficulties for the plan of the propagation model as well as the wearable antenna in this system. To start with, the combination amid the wearable aerial and the humanoid physique must be considered even within the preliminary stages of the layout, with a purpose to be able to cope with each in all likelihood degrading performance of the antenna due to physique and the probability of revaluation for the physique. Later, the transmission medium of the Wireless Body Area Networks is controlled through the non-stop motion of the human body, as a result of the dissipation of the electromagnetic waves at different intervals. Many scholars are involved in the above subject then certain considerable development has been completed lately. The present article recollects today's consequences in the zone of aerials fixed in the physiques, transmission medium and then individual software in Wireless Body Area Network systems. This review discloses the major improvements of physique aerials involved by the part of fixable in the physiques and non-fixable in the physiques Ultra-Wide Band method then their applications in the Wireless Body Area Network device and methods for reducing SAR in them. [ABSTRACT FROM AUTHOR]

This paper presents a novel miniaturized antenna with a dual-band resonance covering the medical body-area network (MBAN) and a 5.8-GHz industrial scientific medical band. Owning to its stacked-patch structure, the proposed antenna generates an omnidirectional radiation pattern with vertical polarization and a broadside radiation pattern with circular polarization at the two bands, respectively, thus fulfilling the requirements for both on- and off-body channels simultaneously. This antenna is designed on a multilayer tissue model, and is then validated on the Gustav voxel model. The footprint of the proposed antenna is only 0.18\lambda 0 \times 0.18\lambda 0 \times 0.04\lambda 0 . The proposed design is fabricated and its performance is investigated in various scenarios. When measured on the pork trunk, impedance bandwidths of 2.8% at the lower band and 9.0% at the upper band are achieved, fully covering the two bands. Besides, the transmission performance at the MBAN band is also studied by conducting measurements on the human body, and the measurement results agree well with the simulation. The obtained robust antenna performance reveals that the proposed design is suitable for MBAN applications. [ABSTRACT FROM AUTHOR]

In this paper, performance of a Swastika slot-ultra-wideband (SS-UWB) patch antenna for an on-body application is investigated. This antenna is intended for the use in UWB wireless body area network (WBAN) applications, between 3.1 and 10.6 GHz. The proposed antenna is a SS-UWB patch antenna of dimension 27 mm × 27 mm × 1.6 mm. It is fabricated and tested in free space scenario instead in anechoic chamber to obtain more realistic on-body measurement results. This SS-UWB patch antenna covers the ultra-wide frequency spectrum in the range 4.25–12.5 GHz [8.25 GHz] with a quasi-omni directional gain from 1.77 to 5.6 dB. This antenna's efficiency is from 81.3% to 90.67% (−1.8 to −0.85 dB) over free space. The antenna is characterized in free space as well as on body model with and without antenna body gap. Measured results obtained from the antenna like S 11 , radiation pattern, antenna efficiency, and gain are matched with the simulated results. [ABSTRACT FROM AUTHOR]

ABSTRACT A dual-band on-body antenna for in-on-on wireless body area network repeater applications is proposed. This antenna consists of a dual-patch antenna and a zeroth-order resonance (ZOR) element. The two patch antenna elements form dual resonances that cover the 2.4 GHz ISM band. In addition, a triangle cut made at the lower edge of patch Element 1 improves the impedance matching in the 2.4 GHz ISM band. The ZOR element operates in the 403 MHz MICS band. The antenna has near surface radiation in the 2.4 GHz ISM band and nearly omnidirectional radiation in the 403 MHz MICS band. To evaluate the performance of the antenna on a human body, the proposed antenna is placed on a human equivalent flat phantom. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:436-441, 2016 [ABSTRACT FROM AUTHOR]

In this paper, a low-profile dipole array antenna with monopole-like radiation for on-body communications is proposed. The proposed antenna, operating in the industrial, scientific, and medical (ISM) band, is designed with consideration of the human body effect. By placing eight planar dipole antenna elements symmetrically around the z-axis, the proposed antenna achieves monopole-like radiation characteristics with a low profile. The antenna has overall dimensions of 0.44 λ0 × 0.44 λ0 × 0.013 λ0 at 2.45 GHz in the ISM 2.45 GHz band (2.4.2.485 GHz) and a 10- dB return loss bandwidth of 4.9% ranging from 2.4 to 2.52 GHz. [ABSTRACT FROM AUTHOR]

A very compact low-profile (37.6\ mm\times 27\ mm\times 3.1\ mm) unidirectional UWB antenna is proposed for wireless body area network (WBAN) localization applications by focusing on its ranging performance and impulse fidelity in time domain in addition to frequency domain characteristics. The antenna is immune to direct skin contact, and also demonstrates very good frequency and time domain properties in free space or at any distance to a body: reflection coefficient and radiation pattern resilience to body influence; flat transfer function amplitude and linear phase over the desired frequency band from 6 GHz to 9 GHz. Superior time domain performance is demonstrated in simulation and measurements with average impulse fidelity of 97% in both free space and when placed at 0 mm or 3 mm over the body. Off-body ranging measurements show accuracies of the order of 5 cm and achievable range higher than 5 m for almost all frontal directions (16 m being the maximum), with transmitting power complying with the international regulation. [ABSTRACT FROM PUBLISHER]

ABSTRACT A higher order mode (TM31) circular-ring patch on-body antenna with shorting pins for on-body communications in wireless body area network is proposed. Using shorting pins, TM31 resonance mode was generated, while achieving compact low-profile structure with monopole-like radiation characteristics. To obtain wide bandwidth, an annular ring with shorting pins having TM31 mode is closely located around the circular patch. The antenna has the overall dimensions of 0.49 λ0 × 0.53 λ0 × 0.025 λ0 at 2.45 GHz in the industrial, scientific, and medical 2.45 GHz band (2.4-2.485 GHz) and the 10-dB return loss bandwidth is 7.3% ranging from 2.35 to 2.53 GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1543-1547, 2014 [ABSTRACT FROM AUTHOR]

Previous works have shown that wearable antennas can operate ideally in free space; however, degradation in performance, specifically in terms of frequency shifts and efficiency was observed when an antenna structure was in close proximity to the human body. These issues have been highlighted many times yet, systematic and numerical analysis on how the dielectric characteristics may affect the technical behavior of the antenna has not been discussed in detail. In this paper, a wearable antenna, developed from a new electro-textile material has been designed, and the step-by-step manufacturing process is presented. Through analysis of the frequency detuning effect, the on-body behavior of the antenna is evaluated by focusing on quantifying the changes of its input impedance and near-field distribution caused by the presence of lossy dielectric material. When the antenna is attached to the top of the body fat phantom, there is an increase of 17% in impedance, followed by 19% for the muscle phantom and 20% for the blood phantom. These phenomena correlate with the electric field intensities (V/m) observed closely at the antenna through various layers of mediums (z-axis) and along antenna edges (y-axis), which have shown significant increments of 29.7% in fat, 35.3% in muscle and 36.1% in blood as compared to free space. This scenario has consequently shown that a significant amount of energy is absorbed in the phantoms instead of radiated to the air which has caused a substantial drop in efficiency and gain. Performance verification is also demonstrated by using a fabricated human muscle phantom, with a dielectric constant of 48, loss tangent of 0.29 and conductivity of 1.22 S/m. [ABSTRACT FROM AUTHOR]