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Inductive coupled loop (ICL) is a matching technique common in UHF RFID tags. In this paper ICL matching is implemented using two antennas one has copper as the radiating antenna and FR4 as a substrate, while the other design is built using silver nanoparticle ink printed on white PET paper. The two antennas are simulated and measured to highlight the effect of using flexible thin material on antennas for RFID tags.

International audience

A MEMS electrostatic kinetic energy harvester (e-KEH) of about 1 cm2, working at ultralow frequency (1–20 Hz), without any supported additional mass on its mobile electrode, and working even without a vacuum environment is reported. The prototype is especially suitable for environments with abundant low frequency motions such as wearable electronics. The proposed e-KEH consists of a capacitor with a finger-teeth interdigited comb structure. This greatly reduces the air damping effect, and thus the capacitance variation remains important regardless of the presence of air. With the new design, the energy transduced per cycle of excitation is no less than 33 times higher than the classic design within 10–40 Hz/2 gpeak, while is 85 times higher at 15 Hz/2 gpeak. An enclosed miniature ball combined with non-linear stoppers enables the oscillation of the movable electrode through impact-based frequency up-conversion mechanism, which is also improved by the low air damping. Thanks to this new design, a higher efficiency than the classic gap-closing comb structure is obtained, as a larger range of working frequency (1–180 Hz) in air. A maximum energy conversion of 450 nJ/cycle is obtained with a bias voltage of 45 V and an acceleration of 11 Hz, 3 gpeak. Working with a diode AC-DC rectifier, the proposed KEH is able to support up to 3 RFID communications within 16 s while operated at 11 Hz, 3 gpeak.

This communication describes the embedding of UHF RFID tags dedicated to power supply cords. A general purpose commercial RFID module is coupled to microstrip dipoles to realize tags, which are wrapped and taped around the cords. The tag dimensions are optimized for a maximum power transmission to the chip and a maximum reading distance in the presence of the cord. Experimental read ranges of the order of 5 m are obtained, whereas commercial tag outperforming the optimized tag in free-space only performs well at 2 m on power cords.

A statistical analysis of the coupling in a set of thin randomly distributed dipoles is presented. The impedance matrix of the set is obtained using the IEMF technique and validated by NEC. The input impedance of each surrounded dipole can be calculated for any arbitrary loading of the surrounding dipoles. The cumulative distributed functions are presented for different dipole densities and the mismatch of a surrounded dipole is studied as a function of the surrounding loading.

International audience; We report an energy-autonomous Radio Frequency IDentification (RFID) tag system which is powered by an electrostatic MEMS-based Vibration Energy Harvester (e-VEH). The VEH is designed specifically for the vibrations of low frequency around 10 Hz. An energy of 80 nJ/cycle can be delivered when the VEH is loaded with an optimal resistor and a bias of 20 V. An RFID chip is powered by the current released from a 1-μF capacitor, which is charged by the VEH through a diode rectifier. The read range of the tag is increased from 2.5 m (under batteryless mode) to 15 m when powered by the VEH working with an acceleration of 2 grms and 10 Hz. The energy of the VEH stored in the capacitor within 40 s can sustain up to 3 tag readings.

This letter reports the characterization procedure of a radio frequency identification (RFID) tag powered by a microelectromechanical system vibration energy harvester (VEH). The tag antenna and its matching interface to the RFID chip are designed with the help of an electromagnetic simulator. The energy provided by the VEH is stored in a reservoir capacitor and released through a mechanical switch to the tag. It is demonstrated that the tag can communicate with a reader at a distance up to 15 m when powered by the VEH working with an acceleration of 2 $g_{rms}$ and 100 Hz. The energy delivered by the VEH within 100 s can sustain up to six tag readings using the EPC Gen-2 Class-1 standard.

The proposed model of the human torso is principally a host sphere, filled with muscle tissue, wherein three eccentric spherical inclusions are accommodated. Two of them are twins and represent the lungs, whereas the third, referred to as the abdomen, represents all human organs beneath the diaphragm. The host sphere is surrounded by two concentric layers, which represent skin and fat. The dyadic Green's function (dGf) of this nonspherical body is determined by application of the principle of superposition and by enforcement of the boundary conditions on all interfaces. The outcome is a set of linear equations for the vector wave amplitudes of the dGF, and that set is solved by truncation and matrix-inversion. Once this is done, the dGf is available as a sum of dyads, and the electric-field intensity can be determined by integration of the dGf, dot multiplied by the current density of the source. The numerical results correspond to an electric Hertz dipole placed near the waist, i.e., the equator of this torso model, and radiating at a WiFi frequency. Plots of the electric-field intensity along the waist and field maps across the equator plane manifest how protected the internal organs are from the external point source, which is practically attached to the surface, and how sensitive to internal organs is the field on the waist.

Radiation from an encapsulated Hertz dipole, eccentrically implanted in a layered spherical body, is determined by use of the dyadic Green’s function (dGf) theory. The body, a model of the human torso, comprises skin and fat layers around a homogeneous tissue core. The capsule is a spherical cavity bounded by an insulating layer. The dGf of this radiation problem involves two reference points, the center of the body and the center of the capsule. The analysis results in a concise formulation of the dGf and of the main radiation quantities. Numerical results are shown for the radiated power, efficiency, and directive gain of the Hertz dipole versus the capsule displacement from the center of the body. Specific absorption rate (SAR) maps are drawn on two cross sections of the body in search of the entire distribution of SAR and the location of peak SAR.

IEEE-NEMS 2016 - The 11th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Matsushima Bay, JAPON, 17-/04/2016 - 20/04/2016; We describe the prototyping of a battery-powered, RFID-enabled carbon nanotube strain sensor for concrete strain and crack monitoring. A series of 10 prototypes has been embedded in a real structure. After a year it is still providing valuable information on the state of the structure. The final volume of the embedded module is 43cm3, the lowest volume reported to date in the field of embedded monitoring of concrete.

A high-temperature tolerant pattern diversity antenna is presented for body wearable applications in hostile conditions. The proposed system consists of a dielectric resonator antenna (DRA) placed at the centre of a slot loop antenna. The combination yields pattern diversity with broadside and endfire radiation patterns from slot loop and DRAs, respectively. The antenna system offers common bandwidth of 4.95% with port isolation of better than 13 dB at 2.4 GHz. The thermal characteristics of antenna have been studied for high-temperature operation and no discernible change in the radiation behaviour is noted. The antenna undergoes 2% resonant frequency shift when operated at elevated temperature. The antenna diversity has been measured for three on-body communication channels. The antenna offers 9.5 dB diversity gain in a pure non-line-of-sight channel surrounded by a rich fading environment subjected to the selection combining scheme. The antenna has dimensions of 0.4λo × 0.4λo × 0.1λo .

International audience; Conducting polymers have found significant applications in the past decade in industrial, scientific, and medical (ISM) fields. The characteristic features of conducting polymers like reversible proton doping, variable conductivity, facile synthesis, and low cost make them potential candidates in various microelectronic applications. Conventional microwave absorbing materials such as carbon and graphite in the powder form were blended with polyaniline as base at different proportions and microwave properties such as transmission, reflection, and shielding efficiency (SE) were evaluated from S parameter measurements using HP 8714ET network analyzer. The newly, developed polyaniline blend exhibits high-electromagnetic interference shielding efficiency when compared with previously developed materials and is a promising candidate for shielding applications. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 393-397, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOT 10.1002/mop.24939

As many applications with antennas placed near an interface are getting developed, it becomes necessary to take properly into account the impact of this interface in the wave propagation. In this article, it is shown that the classical ray-tracing approach may lead to inaccurate results, so a rigorous modeling must be envisaged. The Green's functions of this problem, written as Sommerfeld integrals, offer the possibility to deduce important guidelines which help to better understand and handle this kind of propagation.

Radio frequency identification (RFID) technology is one of the key technologies to make possible the Internet of Things (IoT). There are increasing needs to localize multiple RFID-tagged items which are closely spaced. As a result, localization techniques with higher accuracy yet low implementation complexity are required. This paper examines the applicability of the direction-of-arrival (DOA) estimation techniques using receiving uniform linear array for the localization of passive RFID tags. The theory is validated by experimental results using a dedicated measurement platform.

International audience; A new procedure to measure the apparent reflection coefficient ofdifferential patch antennas at 60 GHz is described. The measurementmethod makes use of two WR15/microstrip-line (MSL) transitionswhich are simple to realise. The experimental results are comparedwith simulated results. This comparison emphasises the limited effectof transition losses on measurement accuracy.

NICOM 5 - Fifth International Symposium on Nanotechnology in Construction, CHICAGO, ETATS-UNIS, 24-/05/2015 - 26/05/2015; In this work we propose a wireless architecture for embedded monitoring in concrete. The modular structure of the system allows it to be adapted to different types of sensors. We present the application of such architecture for the detection of microcracks in concrete. A carbon nanotube strain sensor recently developed by the group is used to track mechanical deformations. Full temperature compensation is achieved by a specific conditioning circuit.

Tagging power cords is not only useful for tracking insulated or hidden electrical cables. Implementing sensory functionalities to the UHF RFID tag in addition to its unique ID is of great interest in the wireless sensing of house electrical appliance activities. Tags dedicated to electrical cables for read distances of 10–12 feet are commercially available (Sentry cable RFID Tag, Vizinex company). The core of the tag is a fiber-reinforced composite material and the mounting uses zip ties or metal banding which makes these tags bulky. Therefore, this type of tags can only be fixed on cables once the electrical installation is complete.

In this work we propose a wireless architecture for embedded monitoring in concrete. The modular structure of the system allows it to be adapted to different types of sensors. We present the application of such architecture for the detection of microcracks in concrete. A carbon nanotube strain sensor recently developed by the group is used to track mechanical deformations. Full temperature compensation is achieved by a specific conditioning circuit.

This Letter points out the drop in radiation efficiency observed in active microstrip antennas with switching capabilities for inadequate values of the bias current. For a frequency agile antenna based on p-i-n diodes, a trade-off between the dc consumption of the diodes and the antenna gain is demonstrated. It is also shown that this type of integrated active antenna can be reasonably predicted by a simple resistor model of the diode in a TLM analysis. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 44–47, 2002; DOI 10.1002/mop.10226

Wireless body area network (WBAN) defines a network of wearable devices showing wireless communication capabilities. First, WBANs were initially used in the healthcare domain for continuous monitoring and logging vital parameters of patients suffering from chronic diseases (such as diabetes). Sports, military, or security were other applications [1]. Body-worn antennas have two requirements: they must be efficient in the presence of biological tissues and their polarization/pattern features should match the incoming direction and the polarization of the incident waves. In a radio link between two body-worn antennas, several types of waves contribute to the channel, i.e. creeping and surface waves guided around the body surface, direct waves, waves reflected/scattered by the environment (ground, walls, etc.), and waves reflected by other parts of the body (legs or arms). As a result, deep fadings are commonly observed and antenna diversity makes sense to fight the fadings in the BAN context [2–6]. In [2], it was demonstrated that on-body antenna diversity is less effective for line-of-sight (LOS) links like the waist–chest link. In [3], the spatial diversity was investigated for monopoles at 2.4, 5.8, and 10 GHz and it was shown that the best diversity gain is obtained at any frequency for the waist–head and waist– ankle links, i.e. for non-line-of-sight (NLOS) links. In [4], space and pattern diversities were tested with monopoles (space diversity) and annular slot-monopole antennas (pattern diversity), the conclusion being that space diversity is the best choice at 2.45 GHz for spacings as small as 3 cm (~l0/4). In [5] and [6], planar inverted-F antennas (PIFAs) and printed IFAs were used to evaluate the influence of the antenna orientation. All these studies conclude that a good diversity gain is only reached for NLOS channels and dynamic channels with large movements.

The purpose of this paper is to clarify the principles, advantages and disadvantages of commercial RFID modules combining a loop and a RFID IC for the excitation of dipole-like antennas. Using a circuit modeling of the tag topology, the influence of the main parameters (dipole radiation resistance and Q factor, module position along the dipole, mutual coupling between the loop module and the dipole) are stressed. A special attention is brought to the determination of the optimal coupling for a given dipole.

Different approaches based on various wireless technologies have been proposed so far for indoor localization. Radio frequency Identification (RFID) indoor localization seems to be a promising way of research. The identification capability of this technology combined to localization methods improves the results obtained by other wireless technologies such as Wifi, GPS, Zigbee. This paper details some localization techniques used for RFID Tags localization in Indoor environment. In particular, Fingerprinting methods are compared to Distance estimation methods. We will show through several simulation experiments, using NS2 and Matlab software, that fingerprinting techniques outperform Distance estimation techniques for localization and tracking tasks.

International audience

A 60 GHz differentially-fed four-port printed antenna (DFFPPA) is proposed in the context of a high data rate transmitter. The transmitter architecture is based on the Impulse Radio Multi-band On Off Keying (IR-MBOOK). The transmitter contains two differential power amplifiers (DPA) whose outputs are directly connected to the DFFPPA which is excited by two differential feeds through two slots. The first slot is excited by the differential outputs of the first DPA, which covers bands 1 and 2 from 57.05 to 60.27GHz. The differential outputs of the second DPA, which covers bands 3 and 4 from 60.3 to 63.7 GHz, excite the printed antenna through the second slot. Simulated results gains around 7.1 dBi are obtained for each differential output. The transmitter architecture promises high data rate and low power consumption in a compact surface.

International audience; A simple topology is described for radio frequency identification(RFID) tags mountable on metal surfaces. The tag is built around acommercial UHF RFID module combining an IC and a couplingloop. The module is placed in the neighbourhood of a slot which isused both to couple the energy from the module to the patch-likeantenna and to miniaturise the tag. A read range of almost 4 m isobtained in the 865–868 MHz band with a 1.6 mm low-cost FR4substrate.

International audience; We propose in this paper two microtrip planar antennas dedicated to a 60 GHz high data rate Impulse Radio Multi-band On Off Keying (IR-MBOOK) low power consumption transmitter architecture. The planar antennas were designed and simulated on a conventional and low-cost RT/Duroid 5880 substrate, and then are connected after two differential Power Amplifiers. The antennas serve for radiation as well as an out-of-phase power combiner. In this solution, the 57.05-63.7GHz dedicated band is separated into four balanced sub-bands. We propose the use of two differential planar antennas to cover the dedicated bandwidth on the transmitter architecture. An antenna covers the first 57.05-60.257GHz sub-band (band 1 and 2) and a second antenna covers the 60.257-63.7GHz sub-band (band 3 and 4). The planar antennas 1 and 2 were designed and simulated using the electromagnetic HFSS software and they give a maximum gain of 9.81 dBi and 10.03 dBi, respectively.

This paper investigates the dual-frequency operation of a stacked microstrip antenna based on a small parasitic patch inserted slightly above an EBG patch. It is shown that the periodic texture of the EBG patch exhibits different behaviours for each frequency. It is also demonstrated that the high-impedance concept is no longer valid when a parasitic patch is located too close to the EBG material. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 207–209, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20589

International audience; A compact dual pattern diversity antenna combining a slot loop and a dielectric resonator antenna (DRA) is presented for body area network (BAN) applications at 2.4 GHz. A common bandwidth of 1.5% is obtained with an isolation of -12dB. The slot loop provides slightly asymmetric broadside radiation patterns while purely symmetric end-fire type radiation patterns are obtained with the DRA. The diversity gain performance of the antenna has been tested in receiving mode for three different on-body communication channels.

Compact Antennas for Wireless Communications and Terminals deals with compact microwave antennas and, more specifically, with the planar version of these antennas. Planar antennas are the most appropriate type of antenna in modern communication systems and more generally in all applications requiring miniaturization, integration and conformation such as in mobile phone handsets.The book is suitable for students, engineers and scientists eager to understand the principles of planar and small antennas, their design and fabrication issues, and modern aspects such as UWB antennas, reconfigurable antennas and diversity issues.

International audience; A miniaturized diversity antenna dedicated to wireless body area network (WBAN) applications is described. The combination of a planar inverted-F antenna (PIFA) and a top-loaded monopole yields distinct patterns fitting the different natures of the received waves. The strong isolation observed between the broadside and endfire ports is an important feature to limit the correlation between the received signals. The diversity gain is measured for three links and three scenarios between body-worn antennas, showing the improvement brought by the antenna diversity in the WBAN context.

International audience; The first results achieved in the French ANR (National Research Agency) project BANET (Body Area NEtwork and Technologies) concerning the channel characterization and modeling aspects of Body Area Networks (BANs) are presented (part II). A scenario-based approach is used to determine the BAN statistical behavior, trends, and eventually models, from numerous measurement campaigns. Measurement setups are carefully described in the UWB context. The numerous sources of variability of the channel are addressed. A particular focus is put on the time-variant channel, showing notably that it is the main cause of the slow fading variance. Issues related to the data processing and the measurement uncertainties are also described.

This article presents measurements performed with test infrastructures for digital TV broadcasting (DVB-SH standard).The objective is to determine the diversity performance of a mobile terminal integrating two orthogonally polarized antennas in various sites. The performance evaluation is based on a narrow band analysis of the propagation channel. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2145–2148, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25361

International audience; This work describes the design of a radiation pattern reconfigurable microstrip antenna electrically controlled by packaged Radio frequency micro-electro-mechanical system (RF MEMS). The antenna operates at 12 24 GHz with good return loss characteristics and a similar to 7 5 dB gain at +/- 30 degrees scan angles from broadside direction in the II-plane. The integratino of packaged RF MEMS and associated bias network is also explained. (C) 2010 Wiley Periodicals, Inc Microwave Opt Technol Lett 52 574-577, 2010. Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.24978

International audience; A theoretical method based on the induction equivalence principle and Green's functions is presented here to calculate the scattered electromagnetic fields from exterior plane building facades in urban environment. The reflection coefficient of the whole inhomogeneous structure can be calculated for different incidence angles. The derivation of appropriate Green's functions is presented. The method takes into account the large-scale discontinuities on the facade. It is simple to implement and fast to obtain results because of the absence of poles in the Green's functions expressions. The accuracy of the method is discussed comparing to a commercial software and physical optics as another method based on equivalent currents. The article concludes with a statistical study on the influence of concrete permittivity variation on the reflection coefficient of a concrete-glass building facade.

International audience; Reduction of specific absorption rate (SAR) has now become a buzz word because of the growing health concerns over microwave exposure. Ferrites are found to be effective in diminishing electromagnetic influence. In this reported work, flexible polymeric ferrite sheets are characterised on the basis of their shielding efficiencies. SAR measurements are carried out with a planar wearable antenna and polymeric ferrite shielding to confirm its competence.