Christophe Roblin

Ultrawide Bandwidth RFID: The Next Generation?

Future advanced radio-frequency identification (RFID) systems are expected to provide both identification and high-definition localization of objects with improved reliability and security while maintaining low power consumption and cost. Ultrawide bandwidth (UWB) technology is a promising solution for next generation RFID systems to overcome most of the limitations of the current narrow bandwidth RFID technology such as: reduced area coverage, insufficient ranging resolution for accurate localization, sensitivity to interference, and scarce multiple-access capability. In this paper, a survey of current progress in the application of the UWB technology for RFID systems is presented with particular attention to low-complexity solutions for high-definition tag localization.

Ultra-wide bandwidth backscatter modulation: processing schemes and performance

Future advanced radio-frequency identification (RFID) systems are expected to provide both identification and high-definition localization of objects with improved reliability and security while maintaining low power consumption and cost. Ultrawide bandwidth (UWB) technology is a promising solution for next generation RFID systems to overcome most of the limitations of current narrow bandwidth RFID technology, such as reduced area coverage, insufficient ranging resolution for accurate localization, sensitivity to interference, and scarce multiple access capability. In this article, the UWB technology is applied to passive RFID relying on backscatter modulation. A signaling structure with clutter and interference suppression capability is proposed and analyzed. The potential performance is investigated in terms of range/data rate trade-off, clutter suppression, and multiple access capability using experimental data obtained in both the controlled and realistic environments.

Robust planar stripline monopole for UWB terminal applications

A fully planar UWB monopole with dual feed is designed for low cost applications over the [3.1-6] GHz frequency band. The achieved input bandwidth is [2.9-7.9] GHz for a size of 40 /spl times/ 24 /spl times/ 3 mm. The chosen stripline technology allows feeding circuit isolation from antenna radiation, and provides robustness to the 20 mm height protruding square-like monopole. The main drawback of such a fully planar design is the degradation of the omni-directionality beyond the first octave. The frequency radiation pattern dependency is investigated and evaluated with specific UWB characterization tools. At last a comparison between 2 monopoles with different technologies helps to settle the compromise between complexity/cost and global performance.

Small semi directional antenna for UWB terminal applications

The design of an ultra wide band (UWB) semi-directional antenna is presented. Both antenna optimizations by simulation and measurement results are presented. The final prototype size is 33 mm times 20 mm times 11.5 mm. The achieved input bandwidth is 3.9-15 GHz. The maximum boreside realized gain (BRG) is 7.5 dBi and the maximum Front-to-Back-ratio (FTBR) is 13 dB. The frequency variance of the antenna gain is exploited in a two-antenna radio link in order to compensate that of free space attenuation.

Probe fed stacked patch antenna for UWB

A microstrip patch antenna with two E-shaped stacked patches for UWB sectoral applications is proposed in this paper. The E-shaped patch antenna has an impedance bandwidth of about 34%. By adding a second E-shaped patch at the top of the first patch a bandwidth of 54% has been obtained. The characteristic dimensions of the second patch as well as the shift between the two patches have been optimized to achieve the ultra-wide bandwidth and radiation pattern stability over the whole band. The distorting nature of this antenna has been quantified using time domain characterization tools and the influence of the ground plane on impedance bandwidth and radiation has been studied.

Characterization of the UWB on-body propagation channel

Wireless body area networks (WBANs) are becoming an increasingly important part of the wireless communication system. In such a communication system various electronic devices carried by a person on his body can be connected. In this paper, we investigate the UWB body area propagation channel. The channel characterization is based on UWB on-body channel measurements. This paper describes the measurement campaign and the basic characteristics of the body area propagation channel extracted from measurement data.

Analysis of UWB Tag Backscattering and Its Impact on the Detection Coverage

The joint adoption of RFID and UWB technologies is a promising solution to overcome most of the limitations of current RFID systems. In particular, UWB RFID based on the modulation of the backscatter signal represents a good option when tags cost, size and power consumption are stringent requirements. In this context, while for current UHF RFID systems an extensive literature is present, only few studies have concentrated on the backscattering of UWB signals. In the present work, we deal with the electromagnetic analysis of the UWB RFID tag backscattering, which is adopted to characterize the interaction of the tag with a close object. We investigate tag backscattering first from an analytical perspective, then through simulations and measurements. Measured data is then post-processed, and performance in terms of detection coverage analysis is finally assessed to evaluate the effects of an object in proximity to the antenna.

Investigation and Modeling of the UWB On-Body Propagation Channel

Wireless Body Area Networks (WBANs) are becoming an increasingly important part of the wireless communication system. In such a communication system various electronic devices carried by a person on his body can be connected. In this paper, we investigate the UWB body area propagation channel. The channel characterization is based on UWB on-body channel measurements. This paper describes the measurement campaign and the basic characteristics of the body area propagation channel extracted from measurement data.

UWB Antenna Performance Evaluation from the Communication System Point of View

This work discusses the performance of ultra wide band antennas in the context of communication systems. An analysis of the physical origins of antenna imperfections is first presented, followed by the definition of modulation and detection scheme dependent radiation patterns. The extension of the analysis to radio links involving a multipath channel is then carried out. The discussion is supported by a variety of antenna measurements and simulations, and makes use of an angular statistical multipath channel model.

Modeling of the influence of body-worn antennas upon the Path Loss variability in UWB WBAN scenarios

The achieved work on the propagation channel of Wireless Body Area Networks has reached today a significant level. However, a large dispersion of reported results, notably as regards Path Loss is observed, both in anechoic chamber and in indoor premises. This work is motivated by this context, the main objectives being on one hand to explain (at least partly) and on the other hand to reduce this dispersion. Measurements have been performed in an anechoic chamber with two human subjects over a 1–12 GHz frequency band. A comparative analysis of the Path Loss involving nine UWB antennas of various types is presented for the Hip-to-Chest and Hip-to-Wrist scenarios. A statistical analysis of the corresponding dataset with a parametric approach with respect to various UWB frequency bands, antenna distance from the body and arm position is exposed next. Parametric models depending on either parameter extracted for various bands, are finally provided. The main objective of is to reduce the variances of the resulting statistical models through a parametric approach and categorization of antennas.