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Using wireless sensors worn on the body to monitor health information is a promising new application. To realize transceivers targeted for these applications, it is essential to understand the body area propagation channel. Several numerical, simulated, and measured body area propagation studies have recently been conducted. While many of these studies are useful for evaluating communication systems, they do not directly consider physical propagation mechanisms forcing researchers to rely on ad-hoc modeling approaches that are not always motivated by fundamental electromagnetic principles. This can result in less insight into expected propagation trends and inappropriate modeling choices. To address this problem, we have developed a simple and generic body area propagation model derived directly from Maxwell's equations. We then verify the resulting analytical model by comparing it with measurements around a body in an anechoic chamber. This paper describes the analytical derivation of this model and compares it with measurements of the electric field close to the body.

In this paper, spatial correlations are studied for the development of a UWB multi-sensors MIMO Body Area Network system, where the sensors communicate with a multi-antenna central device. The correlation in the frequency and delay domains has been extracted from channel measurements on the human body. (5 pages)

Uniquely, this book proposes robust space-time code designs for real-world wireless channels. Through a unified framework, it emphasizes how propagation mechanisms such as space-time frequency correlations and coherent components impact the MIMO system performance under realistic power constraints. Combining a solid mathematical analysis with a physical and intuitive approach to space-time coding, the book progressively derives innovative designs, taking into consideration that MIMO channels are often far from ideal. The various chapters of this book provide an essential, complete and refreshing insight into the performance behaviour of space-time codes in realistic scenarios and constitute an ideal source of the latest developments in MIMO propagation and space-time coding for researchers, R&D engineers and graduate students. Features include • Physical models and analytical representations of MIMO propagation channels, highlighting the strengths and weaknesses of various models • Overview of space-time coding techniques, covering both classical and more recent schemes under information theory and error probability perspectives • In-depth presentation of how real-world propagation affects the capacity and the error performance of MIMO transmission schemes • Innovative and practical designs of robust space-time coding, precoding and antenna selection techniques for realistic propagation (including single-carrier and MIMO-OFDM transmissions)

This paper considers the use of nr times nt dual-polarized arrays for improving the mutual information of MIMO communications. We first develop an elegant model of the multi-polarized MIMO channel, which allows to account for spatial correlation and depolarization effects. The major advantage of the model lies in its analytical expression, whose parameters have a clear physical meaning. In a second part, we investigate the ergodic mutual information of multi-polarized schemes, and derive a condition upon which multi-polarized transmissions offer a higher capacity than equivalent uni-polarized schemes using the same number of antennas under the same overall array dimensions.

In this paper, a physical-statistical approach is used in combination with time series simulations, which rely directly upon distributions of physical parameters and simple electromagnetic theory to predict fade dynamics and shadowing correlation statistics for navigation systems. In the former case, a UTD-based ray-tracing is used with a series of roadside buildings, randomly generated according to known statistical distributions for building height and spacing, street width, etc. When dealing with shadowing correlation statistics for a given satellite constellation, the distribution of the shadowing correlation coefficient is then obtained by deriving time series of first and second elevation angles as well as of azimuth separation, using an orbit generator as input.

The capacity C is usually defined as the maximum error-free data rate that a channel is able to support. A classical assumption while evaluating the capacity of Multiple-Input Multiple-Output (MIMO) channels is to consider the fading co-efficients between the pairs of transmit-receive antennas as independent and identically Rayleigh distributed (i.i.d.). This chapter evaluates the ergodic capacity with perfect channel state information at the transmitter (CSIT), and introduces the popular water-filling algorithm. Then, it considers, with more details, the cases when the system has, at most, a partial (stochastic) knowledge of the channel at the transmitter. Typically, the transmitter is informed about the channel distribution, hence, the denomination CDIT is used for channel distribution information at the transmitter. Both uncorrelated and correlated channels are investigated from an ergodic point of view. The impact of several propagation scenarios on the ergodic mutual information is also considered. The chapter also deals with outage capacity considerations leading to the diversity–multiplexing trade-off.

This paper provides an overview of the state-of-the-art radio propagation and channel models for wireless multiple-input multiple-output (MIMO) systems. We distinguish between physical models and analytical models and discuss popular examples from both model types. Physical models focus on the double-directional propagation mechanisms between the location of transmitter and receiver without taking the antenna configuration into account. Analytical models capture physical wave propagation and antenna configuration simultaneously by describing the impulse response (equivalently, the transfer function) between the antenna arrays at both link ends. We also review some MIMO models that are included in current standardization activities for the purpose of reproducible and comparable MIMO system evaluations. Finally, we describe a couple of key features of channels and radio propagation which are not sufficiently included in current MIMO models.

This chapter develops the theoretical background behind MIMO channel modeling and reviews a large number of physical models as well as a few standardized channel models; and tries to highlight the main advantages and weaknesses of each model, identifying the required assumptions and input parameters. It also highlights multi-polarized channels and antenna coupling models. While dealing with Multiple-Input Multiple-Output (MIMO) channels, space comes as an additional dimension, which needs to be modeled on its own in the same way as time and frequency variations are modeled for wideband Single-Input Single-Output (SISO) systems. This multidimensionality should always be kept in mind while modeling MIMO channels or designing space-time codes. Naturally, the more usual notions, such as the channel stationarity and the channel fading dynamics, must also be considered from a spatial perspective. Stationarity addresses the question of how long the channel statistical behavior remains essentially constant whereas, the channel dynamic properties (represented by the so-called Doppler spectrum) indicate the speed at the stationary channel parameters change over time. These two topics are critical when the signal processing requires the knowledge of the channel at the transmitter. In doing so, it

The performance of space–time codes may be severely affected by the scattering richness, the array design, or the presence of coherent components. As a large variety of propagation conditions is likely to be encountered in practice, there is an obvious appeal to design codes that are robust with respect to all possible propagation conditions. This chapter focuses on this issue, assuming that the transmitter has no prior channel knowledge. Two design methodologies are covered. The first one takes on an information theory approach, while the second one yields design criteria motivated by a physical interpretation of the error probability. Although, information theory and error probability motivated approaches are different, their combination provides a much broader view of the performance of space–time codes in correlated channels. On one hand, the information theory approach obtains a necessary condition to guarantee the approximate universality property—that is, to achieve the high signal-to-noise ratio (SNR) trade-off over any slow fading channel distribution. This condition maximizes the minimum determinant and is similar to the code design obtained for independent identically distributed (i.i.d.) Rayleigh slow fading channels. On the other hand, the error probability motivated approach focuses on a finite SNR behavior by accounting for the presence of fading correlations and/or a coherent component via their interactions with the code words in the particular sets of Rayleigh and Ricean fading channels. However, further research is necessary to investigate the performance of codes designed using both approaches in terms of the diversity-multiplexing trade-off at finite SNR.

Scintillation has an important impact on the earth-space propagation and affects the fade mitigation techniques developed for frequencies above 20 GHz. Scintillation being a random variation superimposed on the signal, it is described by its variance. Most of the exiting models predict the cumulative distribution function (cdf) of scintillation from ground measured parameters, such as temperature and humidity. The use of radiosoundings increases the accuracy of the prediction. Some problems have however to be solved, such as the sensitivity of the cdf to the value of some derivatives used in the calculation. High resolution radiosoundings give better height accuracy but increase the noise present in the calculation. Preliminary solutions are proposed to improve the processing of the radiosonde data and the results are compared with measured data.

The goal of this paper is to investigate the validity of the Kronecker model for MIMO correlated channels. First, mathematical and equivalent propagation conditions of validity are detailed. In a second part, we address several areas where the Kronecker model is not valid. We also review the one-ring model and experimental results dealing with the validation of the Kronecker model. Based on these scarce results, the preliminary conclusion is that the Kronecker model might not be valid for arrays larger than 2times2 when antenna correlations are high across both receive and transmit arrays. The paradox is that the Kronecker model has been developed and is being widely used to account for correlation. This is in strong contrast with the popular belief that the Kronecker model is valid in many indoor and outdoor cases

This contribution provides a fresh look at the asymptotic (in terms of number of antennas) design of multiple-antenna wireless systems, with the goal of giving useful insights on the deployment of future MIMO systems. For the i.i.d. Gaussian and double-directional models, we provide guidelines in terms of the repartition of the antennas between the transmitter and the receiver, and study the influence of array geometry on the ergodic mutual information per antenna. Furthermore, we compare the LOS and NLOS situations, and evaluate the relative importance of the LOS component and path loss in Ricean fading, as well as in the low-rank Ricean component case.

Space-frequency code designs commonly rely on the assumption of independent and identically distributed (i.i.d.) Rayleigh channels. However real-world channels are space and tap correlated. In this paper, we study the impact of spatial and tap correlations on the performance of space-frequency codes. We propose a way to quantify the diversity achieved by any space-frequency code over Rayleigh fading channels with full- rank channel correlation. We show that in order to improve the coding gain, a block interleaver should be used instead of the commonly assumed random interleaver. Finally in order to improve the robustness of space-frequency coding in the presence of space-tap correlated channels, a new design criterion that takes into account the non-idealities of the channel is proposed. No channel knowledge is assumed at the transmitter. I. INTRODUCTION Space-frequency coded MIMO-OFDM with nt transmit and nr receive antennas over a L-tap frequency selective fading channel has drawn considerable attention in the communica- tion society due to the significant gains such systems provide both from the spectral efficiency and link reliability points of view (1)-(10). While it is well known that the maximum achievable diversity order on i.i.d. channels is equal to ntnrL, a way to quantify the diversity achieved by a given code over general MIMO channels has not been proposed. Moreover, coding gain has been generally neglected. It was commonly assumed that the use of random interleaver is a good way to maximize the coding gain. We derive in this paper a method to quantify the diversity achieved by any space-frequency code on MIMO Rayleigh fading channels with full rank channel correlation matrix (i.e. the i.i.d. case is thus a particular case of this study). It is then shown that it is advised to use block interleaver in order to exploit efficiently the frequency diversity. The discussion continues by showing how to make codes robust in the presence of transmit and tap correlations. Therefore a new design criterion is proposed.

Publisher Summary This chapter discusses the physical channel models, the analytical models for multiple-input multiple-output (MIMO) channel, and validation of a MIMO channel model. It aids in the study and measurement of the properties of several propagation channels.. For system design and simulations, analytical models are preferred over the physical models, as they can reproduce the characteristics of various channels without being complicated. In LoBF01, and LoFK02, the wide-sense-stationary uncorrelated scattering (WSSUS) channel formalism is extended to the spatial dimension. Applying a space-time analogy, the signal in the spatial domain is described through replacing time and frequency by spatial location and spatial frequency, respectively. Based on the knowledge of the generalized impulse response and transfer function, discrete sampling filter models are derived. LoFK02 can be implemented in channel emulators with space-time variable gain multipliers. The chapter summarizes that these multipliers have properties similar to small-scale fading and the Gaussian amplitude—resulting from the sum of many multipath components. Integrating this space time channel model with array geometries yields a model of the MIMO channel matrix.

The practical use of so-called analytical models for representing measured and simulated narrowband MIMO channels is discussed with respect to several metrics. Four analytical models are compared (the Kronecker model, the Weichselberger model, the virtual channel representation, and the diagonal-decorrelation model) using several performance metrics. The investigation is based upon indoor experimental results at 5.2 GHz as well as geometry-based statistical propagation models.

This paper describes the extraction of cluster parameters at the user terminal from wideband data measured at 1.9 GHz in short-range outdoor macrocellular environments. Clusters are first identified through data visual inspection. Then, a statistical characterization is carried out based on delay-oriented classification of the clusters. Results show that, at each location, six to eight clusters are present, with average cluster delay and azimuth spreads of about 10 to 15 nanoseconds and 10 to 20 degrees respectively. The model is validated with measurement results, including correlations for broadside and inline receive antenna configurations.

The paper investigates the case of so-called diagonally correlated MIMO channels. This particular type of correlated channel, which cannot result from the popular Kronecker assumption, is shown to provide higher ergodic capacity than uncorrelated fading channels. Interestingly, such channels present a specific symmetry of the channel matrix element amplitudes: their rows are either cyclically right- or left-shifted versions of each other, so that the absolute value of the channel matrix is circulant. The proposed analysis details exemplary physical scenarios leading to high diagonal correlations, first for the simple case of 2/spl times/2 channels, and then for arbitrary array size, n. An analytical expression for capacity is also derived. It demonstrates that the ergodic capacity of diagonally correlated channels grows exactly linearly with the number of antennas.

This communication highlights the impact of channel correlations, including cross-correlation terms, on various relevant metrics, namely the squared channel Frobenius norm and as well as capacity metrics, directly linked with the channel covariance matrix. Using the developed metrics, lie compare various antenna configurations, with a focus on multi-polarized systems. Several orthogonal schemes, such as horizontal-vertical and slant schemes, are investigated, and analytical expressions are presented.

This paper aims at characterizing the wireless channel for nomadic diversity-based systems operating at 1.9 GHz. Using a 1 times 2 wideband measurement chain, four indoor environments have been investigated: a corridor, a small office, an electrical engineering laboratory, and an industrial hall. The measurement equipment is constituted by an 80-MHz transmitter. At the receiver, two omnidirectional antennas are connected to a wideband channel sounder through a switch, in order to measure an estimate of the instantaneous vector channel. Special attention is given to the experimental procedure itself, so as to take into account the specificity of nomadic systems (as opposed to usual mobile systems). The measurement analysis reveals that the shadowing, Ricean K-factor and delay-spread are lognormally distributed. A path-loss model is derived, and cross-correlations between K-factor, delay-spread and shadowing are analyzed. The channel correlations at the user terminal or at the access point are also derived, and related to the individual channel characteristics

The channel capacity and the performance of MIMO systems in the presence of fading correlation and antenna coupling are investigated. Simulation results demonstrate that mutual coupling can improve the performance depending on the inter-element spacing and the richness of scattering. It is shown the bit error rate performance of spatial multiplexing is particularly influenced by the decorrelation/correlation effect caused by mutual coupling. On the other hand, the bit error rate performance of transmit diversity is mainly affected by the resulting modification of antenna gain and received power.

Spatial multiplexing is employed in MIMO communication systems to increase spectral efficiency. The performance of spatial multiplexing is highly dependent on the propagation conditions such as the richness of scattering, the presence of dominant components and the inter-element spacings. In this paper, new robust signal constellations for use in spatial multiplexing over real fading propagation channels are developed. It is shown that these new constellations are by far more robust against fading correlations and high Rice factor than the classical PSK and QAM constellations. With these new constellations, spatial multiplexing presents excellent symbol error rate performance whatever the propagation environment and the inter-element distance.

This communication describes a physically oriented statistical approach that predicts narrowband fading statistics for macro- and megacellular metropolitan networks. The model is successfully compared with experimental data at 1.6 GHz and applied to several simulation schemes including polarization multiplexing.

This paper addresses the extension of a physical scattering model to multi-polarized transmissions. The initial approach is based on a geometrical distribution of obstacles derived from known power-delay profiles. In this paper, each scattering process is described by a matrix reflection coefficient corresponding to dual-polarization states. Ultimately, the model allows one to simulate the effects of the range on capacity, branch power-ratio and cross-polar discrimination. Simulation results are compared with existing measurements at 2.5 GHz. The proposed model is then used to investigate various dual-polarization 2/spl times/2 MIMO schemes, such 0/spl deg//90/spl deg/ or 45/spl deg/, as well as to optimize the design of multi-polarized MIMO schemes.

The paper highlights the impact of channel correlations on the capacity of MIMO communications, with a focus on the so called diagonal correlations. Based on this analysis, the limitations of simplified mathematical representations, such as the Kronecker or the diagonal-decorrelation models, are pointed out. Finally, the correlation properties of characteristic geometrical scattering models are studied in order to analyze whether these models can be adequately represented by the simplified formalisms, as well as to quantify the errors introduced by these simplifications. With respect to channel correlations, neither the Kronecker model nor the diagonal-decorrelation assumptions are good representations of the investigated geometrical scattering models. When comparing capacity values, it is found that the diagonal-decorrelation model may yield significant errors. In particular, relative errors on ergodic or outage capacity may be significant for the Kronecker model.

This special issue is composed of eight articles, which provide an overview of state-of-the-art research in mobile radio channels.

In the design of diversity and fast handover schemes for high-speed railways (HSRs), a better understanding of the shadow fading correlation properties is required. In this paper, both auto- and cross-correlation models of shadow fading in HSR environments are proposed based on a large set of measurements with 6146 cells in China. The measurements are conducted using a practically deployed and operative Global System for Mobile Communications-Railway (GSM-R) system at 930 MHz to reflect the real conditions of shadow fading in HSR environments. Seven typical HSR environments and the realistic base station (BS) parameters are considered in the analysis. It is found that the decorrelation distance is correlated with the standard deviation (STD) of shadow fading and is generally larger than 100 m in most HSR environments. The cross correlation of shadow fading between two neighboring BSs depends on the BS height and the tilt angle of the antenna, and a heuristic truncated Gaussian distribution model of cross correlation is proposed. The model is validated by the measurements conducted in another operative HSR line. The results can be used to exploit the simulation algorithms to analyze the signal-to-interference-ratio (SIR) properties and to develop new and better handover schemes for HSRs.

This communication highlights the influence of edge diffraction on the performance of land mobile satellite (LMS) systems in urban environments. The channel is modelled using a ray-tracing software which evaluates the complex signal received by a mobile terminal moving in a three - dimensional area. This method takes into account the line-of-sight ray plus various contributions generated by reflection from ground and wall surfaces as well as by diffraction on building edges. As diffraction from both horizontal and vertical edges appears to be one of the most significant mechanisms, precise modelling is developed. Single diffraction from an edge of finite length is accounted for by means of a UTD-based edge equivalent current method. Double diffraction is also implemented, but is found to be negligible. The ray-tracing method is applied to produce time-series in a typical urban environment. A canonical wideband scenario is also investigated and predictions of system performance are achieved. It is shown that significant impairments may be attributed to edge diffraction mechanisms.

Cross-polarised antenna systems are an attractive way to reduce equipment size while maintaining low inter-antenna correlation. The cross-polar discrimination (XPD) is an important parameter of cross-polarised systems. Starting from the definition of Ricean fading channels, it is shown that the small-scale variations of the XPD have a doubly non-central F-distribution. The simulated XPD distribution obtained as a function of the Ricean parameters is successfully compared with measurement results for validation.

To model the fast-fading statistics of the wireless transmission channel in indoor peer-to-peer scenarios, an amplitude distribution composed of three distinct components was investigated. They correspond to line-of-sight, once-reflected and twice-reflected propagation paths. It is shown experimentally that this distribution matches indoor peer-to-peer links better than the available alternatives. Furthermore, an interesting structure in the parameter space of the distribution is pointed out, leading to a simple stochastic parameterisation based on a three-modal normal distribution.

Tapped-delay line representations are analysed by presenting an empirical model relating the inter-tap correlation to the tap powers obtained from pedestrian radio channel impulse responses measured at 1.9 GHz. The impact of the filtering bandwidth on the parameters of this model is also investigated.

On-body communications around the human torso are considered, using ultra-wideband transmissions. The velocity of the diffracted wave propagating around the body is extracted from frequency-domain spatial correlation analyses.

The potential beneficial impact of channel correlations on the capacity of MIMO systems is investigated. In contrast to most previous work, the present analysis is based on a comprehensive model of the channel correlation structure. It is therefore illustrated that fading cross-correlations may increase the ergodic capacity, sometimes even beyond the supposedly ideal case of independent channels. Starting from considerations on an analytical upper bound of the capacity, the study is then supported by simulation results of the actual ergodic capacity in arbitrary MIMO channels using a simple geometry-based stochastic model.

Based on a physical-statistical model. an analytical mrthod is developed to predict the coverage of IMT-2000 communication systems based on high-altitude platforms. First, the general modelling approach is presented, together with L-band experimental validation. The particular case of high-altitude platforms is then analysed in the framework of the IMT-2000 standard.

A new diffraction method that yields realistic simulations of the mobile channel in built-up areas is presented. The new model, using UTD-based edge equivalent currents, allows for integrating the finite dimension of building wedges in the field estimation. A comparison with 1.6 GHz experimental data shows good agreement in terms of level-crossing rate, in contrast to results obtained with the basic UTD.

An original method for predicting the performance of upcoming stratospheric communication systems is presented. The prediction is based on a physical-statistical model of the built-up channel, used in combination with existing models of the tropospheric mechanisms. The physical nature of the approach allows the statistics of fade and BER to be obtained as a function of any input parameter, such as the size of the target area, the platform height or the area characteristics. Simulations provide, for example, values of BER achieved over a certain percentage of area during a given percentage of time, as a function of the ground range right below the platform. Various system procedures. such as error correction and power control, are also investigated.

A physical wideband propagation model for the fixed wireless channel, with particular emphasis on K-factor and RMS delay spread and their variation as a function of range and antenna beamwidth, is described. The purpose of the model is to generate a set of spatially distributed scatterers, in accordance with given empirical channel characteristics. The model is successfully compared with existing empirical models.

A ray-tracing model based on the uniform theory of diffraction is briefly described. A comparison between simulation and experimental results at 12.5 and 30GHz is presented. Since measurements were carried out in winter and late summer, they also highlight the effect of vegetation at these frequencies. Finally, the ray-tracing tool is applied to the characterisation of an urban channel at several frequency bands.

A performance analysis of land mobile satellite systems is presented. A physical-statistical model is applied to infer narrowband channel parameters, such as fade distribution, level-crossing rate or bit error ratio. The physical-statistical approach combines a ray-tracing tool with the statistical distribution of the parameters describing the environment. Simulation results are successfully compared with measurements at the L-band. The model is then used to predict the performance of a typical LMS system, with a new point of view, which differentiates temporal availability and spatial coverage. The physical nature of the method highlights the role of relevant parameters.

The paper presents a model of the land mobile satellite channel, predicting the statistical fade distribution in a given urban or suburban area described by objective data. The channel modelling is based on a conditional Rician distribution, whose parameters are related to physical parameters such as building height, street width, azimuth and elevation angles of the satellite link. Relationships between Rician and physical parameters are estimated by means of a ray-tracing method based on the uniform theory of diffraction, and statistically varying physical parameters are described by analytical distributions. The model is applied to a typical suburban area, and very good agreement is found between simulations of the fade distribution and radio measurements at L, S and X bands for two elevation angles.

In this work, we will discuss the modeling of the Power Angular Profile (PAP) of the Dense Multipath Components (DMC), taking into account multiple angular clusters. We have extended the maximum likelihood estimation of the angular DMC parameters in the RiMAX framework, so that the PAP of the DMC can be modeled with a multimodal von Mises distribution. This allows us to better characterize the diffuse scattering between transmitter and receiver, originating from multiple reflections in an environment. We have validated our proposed method with synthetic radio channel data based on Monte Carlo simulations, and have shown the importance of applying a multimodal assumption over a unimodal one.

This work presents a measurement-based polarimetric analysis of the specular- and dense multipath components (SMCs and DMC) in a large industrial warehouse. MIMO channel sounding measurements were carried out in a flower auction warehouse, and were processed with the RiMAX multipath estimation framework. In the analysis, we investigate the behavior of the SMCs and the DMC power as a function of both the polarization and the transmitter-receiver distance for 1507 distinct positions of the receiver. The cross-polar discrimination of the transmitted V and H polarizations were analyzed statistically for this environment, as well as the relative power ratio of the DMC, and the DMC reverberation time.

This chapter provides overview of fundamental definitions, tools and new methods towards improved channel modeling reported in the Co-operation in Science and Technology (COST)-Inclusive Radio Communications (IRACON) Action for future wireless communications and networks. The overview first covers definitions of propagation environments as they determine most relevant propagation mechanisms to consider and model, and furthermore, guide approach to channel modeling methods. This chapter then introduces new insights into popular approaches of channel modeling, i.e., site-specific and geometry-based stochastic channel modeling, where the latter particularly features canonical and standardized channel modeling approaches taken by the 3rd Generation Partnership Project (3GPP), COST, and International Telecommunication Union (ITU) communities. Finally, this chapter shed lights on new modeling approaches to small-scale radio propagation behaviors, covering plane wave propagation paths and distributed diffuse scattering.

International audience; La prolifération sans cesse croissante de systèmes communicants sans fil soulève le problème de leur autonomie énergétique. Les solutions conventionnelles par pile ou par batterie posent de réels problèmes de durée de vie et de recyclage. Le concept de la transmission d'énergie sans fil (TESF) en utilisant le champ électromagnétique lointain apparait comme une solution alternative et potentielle. L'élément clé d'un système de TESF est appelée rectenna (pour rectifying antenna), il contient une antenne de réception et un circuit de conversion RF-DC. Le circuit de conversion RF-DC est souvent constitué d'une ou de plusieurs diodes Schottky, d'un filtre HF en entrée et d'un filtre DC en sortie. Une rectenna est généralement chargée par un élément résistif, qui représente l'impédance d'entrée du dispositif à alimenter. Ce papier décrit la conception et la mesure d'une rectenna efficace en bande ISM à 2.45 GHz, dédiée à l'alimentation de capteurs et d'actionneurs sans fil. Des rendements supérieurs à 80 %, à des densités surfaciques de puissance faibles et moyennes (< 45 μW/cm²), ont été mesurés. La rectenna proposée est composée d'un circuit de conversion RF-DC symétrique à 4 diodes Schottky et de deux antennes patch. Un outil numérique dédié, basé sur la méthode FDTD-3D, a été développé au laboratoire et utilisé. La faisabilité d'alimentation à distance d'un capteur de température par récupération et conversion d'énergie électromagnétique a été démontrée. Le capteur effectue une mesure toutes les 10 secondes et nécessite une énergie d'environ 30μJ.

ISBN : 978-0123821942