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In this paper, a compact dual-band radiator with a modified ground structure is presented for on/off body communication. The antenna is capable of resonating in the ISM-I (2.4 GHz) and WLAN (5.15–5.85 GHz) bands. The proposed antenna consists of a novel compact ring loaded with a C-shaped radiator for dual-band operation. To improve impedance matching and shifting of the lower band at the ISM-I band, a modified ground structure is used. This suggested antenna has a small footprint of 0.24λ0×0.22λ0×0.016λ0, wherever λ0 is the free space wavelength at the lower operational frequency. The proposed antenna is parametrically studied, as well as the analysis of electric field and SAR at different positions on the arm are also carried out to check its utility for medical applications. The proposed antenna's specific absorption rate (SAR) meets IEEE standards and the prototype's measured findings validate the simulation results. [ABSTRACT FROM AUTHOR]

A compact co-planar waveguide (CPW) based triple-band printed conformal antenna for on-body applications is presented in this research. In order to accomplish impedance matching, a coplanar structure is employed with the ground on the same plane, and this is printed on the top layer of a polyimide substrate of 0.6 mm thickness. The proposed conformal antenna consists of two identical patch elements. The radiating element is made up of two split ring resonators positioned on the top of the feeding element. The suggested on-body antenna has an overall miniaturized size of only 35 37.5 mm², making it ideal for use in the biomedical field. The designed antenna is capable to cover various spectrum spanning from 2.387-2.618 GHz, 4.2-4.64 GHz, and 6.23-6.56 GHz with a 2:1 voltage standing wave ratio. The designed antenna is fabricated and antenna parameters are measured which is correlated with simulated results. The antenna achieves a total gain of around 5 dBi with radiation efficiency of up to 95 % over the various operating spectrums. To validate the conformality over curved surfaces, the fabricated prototype of the proposed antenna is bent at 30°, 45, 90° angles and the measured results are compared with simulation results of the bending analysis. Furthermore, to validate the on-body performance of the antenna Specific Absorption Rate has been calculated through simulation and it is found to be lower than 1 W/Kg over all three bands of spectrums which proves that the proposed bio-medical antenna could be a viable candidate for microwave imaging applications. [ABSTRACT FROM AUTHOR]

In this paper, a flexible on-body antenna with frequency reconfigurability for multipurposes is proposed. The proposed antenna has a hexagon-like shape with an on/off short to the ground. It switches between the ISM frequencies 433 MHz (when the switch is on) and 915 MHz (when the switch is off). It works as an on-body receiver for Wireless Capsule Endoscopy (WCE) system implemented at 433 MHz and as a receiver for implanted arm antenna implemented at 915 MHz. The proposed antenna is simulated on a cylindrical phantom of the average dielectric constant of skin, fats, and muscle. The effect of varying the bending radii is studied as well. The proposed antenna is fabricated and then tested on a liquid replicating the average biological material and on the human arm as well. The measured reconfigurable antenna gives good matching at both 446 MHz and 934 MHz. It also matched well on the human arm at the OFF state. Moreover, the fabricated on-body antenna at the ON state is tested as a receiver for the WCE system. The proposed antenna is fabricated on Rogers 5880 laminate and attains a size of 45 × 65 mm². [ABSTRACT FROM AUTHOR]

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]

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]

This paper presents a high gain antenna with a nearly unidirectional radiation pattern. The antenna is composed of concentric complementary split ring resonators (CSRRs) that radiate at different frequencies as determined by the circumference of each ring slot as well as the mutual coupling between them. The antenna is optimized for operation at 2.45 GHz, which is one of the frequencies commonly used for body-worn communication devices. It is found that the concentric CSRRs behave like a filter in the radial direction and prevent surface currents from reaching the edges of the ground plane resulting in broadside radiation. The antenna shows a return loss of higher than 25 dB in both measurement and simulation. The front-to-back ratio (FTBR) is improved by backing the ring slots with a metallic rectangular cavity yielding FTBR of 21.2 dB and gain of 7.87 dB in measurements. The achieved radiation characteristics prove that the designed antenna is a good potential candidate for body-worn communication devices, where human body exposure to radiation must be minimal. [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents a performance analysis of beam-reconfigurable in/on-body antennas. Both antennas operated within the Medical Device Radio Communications Service band (MedRadio band: 401-406 MHz) and were designed to steer the beam directions. To implement the beam-steering capability, the two antennas used two artificial switches. The in/on-body antennas were fabricated on FR-4 and fabric substrate, respectively. A skin-mimicking model ( εr = 46.74, σ = 0.69 S m−1) was adopted for the simulations and measurements of the two antennas. We performed transmission and reception tests between in/on-body antennas in an antenna chamber. The test was implemented in various cases, with different antenna distance and angle values. In addition, we compared received power between the calculated results (by virtue of the Friis transmission equation) and the actual measured results, and summarize these findings herein. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1163-1169, 2016; View this article online at . DOI 10.1002/mop.29750 [ABSTRACT FROM AUTHOR]

This work addresses the design and experimental characterization of on-body antennas, which play an essential role within Body Sensor Networks. Four antenna designs were selected from a set of eighteen antenna choices and finally implemented for both passive and active measurements. The issues raised during the process of this work (requirements study, technology selection, development and optimization of antennas, impedance matching, unbalanced to balanced transformation, passive and active characterization, off-body and on-body configurations, etc.) were studied and solved, driving a methodology for the characterization of on-body antennas, including transceiver effects. Despite the influence of the body, the antennas showed appropriate results for an in-door environment. Another novelty is the proposal and validation of a phantom to emulate human experimentation. The differences between experimental and simulated results highlight a set of circumstances to be taken into account during the design process of an on-body antenna: more comprehensive simulation schemes to take into account the hardware effects and a custom design process that considers the application for which the device will be used, as well as the effects that can be caused by the human body. [ABSTRACT FROM AUTHOR]

On‐body communications show highly polarization selectivity in both radio channels and antennas due to the complex body coupling and scattering effects, and full‐space dimension link distribution. To mitigate the polarization variation of on‐body communication links, multipolarization antennas are proposed to adaptively capture the on‐body channel polarization components. In this article, a tri‐polarization antenna design is introduced with its performance evaluated on a simplified three‐layered human chest model including skin, fat, and muscle tissues. The return loss, frequency response, and the radiation pattern of designed antenna are found to be affected by the relative orientation and distance between the antennas and the trunk, indicating the necessity of the antenna emplacement optimization for realistic on‐body communication devices. [ABSTRACT FROM AUTHOR]