Time Domain Measurements of Signals Backscattered by Wideband RFID Tags

Passive wideband RFID is increasing interest for its capability of providing high-accuracy tag localization in addition to identification and tag-reader communication. The measurement of backscattering capabilities of wideband antennas is usually conducted in the frequency domain by using network analyzers, which does not allow for the extraction of the antenna mode component of the backscattered signal when the antenna load is time variant. To overcome this issue, in this paper we present a novel setup for time domain measurements of signals backscattered by wideband RFID tags. Experimental evaluations are presented for comparing different wideband antennas and show the effects of the setup characteristics and of the processing schemes on the achievable measurement results

An Ultra-wideband Battery-less Positioning System for Space Applications

An ultra-wide bandwidth (UWB) remote-powered positioning system for potential use in tracking floating objects inside space stations is presented. It makes use of battery-less tags that are powered-up and addressed through wireless power transfer in the UHF band and embed an energy efficient pulse generator in the 3-5 GHz UWB band. The system has been mounted on the ESA Mars Rover prototype to demonstrate its functionality and performance. Experimental results show the feasibility of centimeter-level localization accuracy at distances larger than 10 meters, with the capability of determining the position of multiple tags using a 2W-ERP power source in the UHF RFID frequency band.Comment: Published in: 2019 IEEE International Conference on RFID Technology and Applications (RFID-TA

Smart Surface Radio Environments

This Roadmap takes the reader on a journey through the research in electromagnetic wave propagation control via reconfigurable intelligent surfaces. Metasurface modelling and design methods are reviewed along with physical realisation techniques. Several wireless applications are discussed, including beam-forming, focusing, imaging, localisation, and sensing, some rooted in novel architectures for future mobile communications networks towards 6G

Passive UWB RFID for Tag Localization: Architectures and Design

In the new scenarios foreseen by the Internet of Things, industrial and commercial systems will be required to detect and localize tagged items with high accuracy, as well as to monitor the level of certain parameters of interest through the deployment of wireless sensors. To meet these challenging requirements, the adoption of passive and semi-passive ultra-wideband (UWB) radio-frequency identification (RFID) appears a promising solution, which overcomes the limitations of standard Gen.2 ultra-high frequency (UHF) RFID. The design and implementation of such systems pose several practical constraints, impacting the overall network architecture. In this paper, the main issues and challenging aspects for the design of a UWB-RFID network considering architectural and protocol choices are discussed in a unitary framework, and practical solutions, accounting for the presented issues, are proposed. Moreover, the possible integration of UWB-RFID with standard Gen.2 UHF-RFID is proposed as an interesting option, discussing architectural solutions, their advantages, and drawbacks

The future of ultra-wideband localization in RFID

In the new scenarios foreseen by the Internet of Things (IoT), industrial and consumer systems will be required to detect and localize tagged items with high accuracy using cheap, energy autonomous, and disposable tags. To meet these challenging requirements, the adoption of passive ultra-wideband (UWB) radio-frequency identification (RFID) appears a promising solution to overcome the limitations of current Gen.2 RFID standard. In this paper we provide a survey on recent developments in the field of UWB-RFID by discussing the main advantages and open issues in providing high positioning accuracy with energy autonomous devices. Successively, we envision the possible cutting-edge technologies for next generation UWB-RFID as a key enabler for the IoT

High-accuracy localization of backscattering UWB tags: Implementation and experimental results

none4siUltra-wideband (UWB) impulse radio is a technology ideally suited for centimeter-level localization, and especially attractive because of the possibility to employ backscattering tags which can be made energy autonomous. Still, achieving such accuracy in localizing backscattering tags is challenging and requires careful consideration in implementing the signal processing chain. This paper presents signal processing and system approaches for cm-level localization of backscattering tags in a multi-static configuration. We present results of a measurement campaign, where a backscattering UWB system provides localization with an error of 6.5 cm.mixedAleksandravicius, Jurgis; Decarli, Nicolo; Guerra, Anna; Dardari, DavideAleksandravicius, Jurgis; Decarli, Nicolo; Guerra, Anna; Dardari, David

Enhanced localization coverage with Non-Regenerative UWB relays

Real-time locating systems (RTLS) enable a number of new important applications. Their performance is mainly limited by wireless propagation impairments. This paper puts forth the idea to enhance coverage and accuracy of RTLS in the presence of severe non line-of-sight propagation conditions using low complexity non-regenerative ultra-wide bandwidth relays. A maximum likelihood position estimator is derived and the feasibility of relay-based positioning scheme is demonstrated

Establishing Multi-User MIMO Communications Automatically Using Retrodirective Arrays

Communications in the mmWave and THz bands will be a key technological pillar for next-generation wireless networks. However, the increase in frequency results in an increase in path loss, which must be compensated for by using large antenna arrays. This introduces challenging issues due to power consumption, signalling overhead for channel estimation, hardware complexity, and slow beamforming and beam alignment schemes, which are in contrast with the requirements of next-generation wireless networks. In this paper, we propose the adoption of a retro-directive antenna array (RAA) at the user equipment (UE) side, where the signal sent by the base station (BS) is reflected towards the source after being conjugated and phase-modulated according to the UE data. By making use of modified Power Methods for the computation of the eigenvectors of the resulting round-trip channel, it is shown that, in single and multi-user multiple-input multiple-output (MIMO) scenarios, ultra-low complexity UEs can establish parallel communication links automatically with the BS in a very short time. This is done in a blind way, also by tracking fast channel variations while communicating, without the need for ADC chains at the UE as well as without explicit channel estimation and time-consuming beamforming and beam alignment schemes

Energy sprinklers for passive UWB RFID

In passive RFID networks the reading range is often limited by the intrinsic two-hop propagation mechanism. To counteract such effect, in this paper we introduce the idea of energy sprinklers for the recently proposed UWB-UHF RFID networks based on backscatter modulation. In particular, we show how low-complexity sprinklers acting as transmitters significantly improve the capability of reading and localizing tags thanks to the multistatic configuration. Moreover, by exploiting the UHF signaling, sprinklers behave like sources of energy that can be exploited by energy harvesters to activate the UWB backscatter modulators in the tag