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Multi-antenna techniques are typically avoided in passive RFID because of the large footprints required. However, the smaller footprints required at microwave frequencies such as the 5.8 GHz industrial, scientific, and medical (ISM) band allow the use of multiple antennas. Two new multi-antenna technologies are featured in this paper to provide power and communications to a passive wireless tag in...
Power transfer between tag chip and tag antenna plays a critical role in determining the performance of passive UHF RFID systems. However, optimum power transfer is difficult to achieve due to parasitic capacitance introduced during the tag assembly process. Moreover, the parasitic capacitance leads to performance deviation and tag detuning. Thus it is highly desired to determine the parasitic capacitance...
Optimization of wireless power transmission through periodic reinforced concrete structures is studied here. Computational methods are applied to investigate the transmission and reflection coefficients for reinforced concrete slabs as a function of concrete slab thickness and rebar configurations at different frequencies. Electric field induced inside reinforced concrete is also examined. Specifically,...
In this paper, we propose a two-level path authentication protocol for object genuineness verification in RFID-based supply chain and EPCglobal Network. In our solution, a tag's path in a supply chain can be generated dynamically, where each reader in the path can verify the validation of the path using its own private key. Our solution has a few promising properties, including dynamic path generation,...
4-bit microcontrollers (MCUs) are among the simplest, cheapest and most abundant computing devices that, thanks to their low power consumption, may be deployed even in passive RFID tags. Besides, 4-bit MCUs are embedded in a wide variety of daily-life objects that, when connected to a network, could become a substantial part of the Internet of Things. Despite the fact that quite a number of applications...
In this work, we identify RFID tags based on their inherent signal features, which can be another level of security on top of the traditional way of demonstrating knowledge of a secret key. Identification is the process of discovering the true identity of an entity from the entire collection of similar entities and requires one-to-many matching. Passive UHF RFID tags are identified by their signal...
In this paper, we present for the first time a novel optimization procedure which allows to maximize the efficiency of RF-DC energy harvester converters, taking into account the contributions of the matching network. Thanks to this procedure, we have designed and realized a CMOS RF-DC converter operating in a very wide range of input power −14÷+1dBm with a peak efficiency of 45% The RF-DC converter...
An active MOS diode for low voltage and low power RFID rectifiers is presented. The diode is based on the technique with internal threshold cancellation (ITC) for MOS diodes and uses a simple control scheme to minimize the diode reverse leakage so that full threshold cancellation is achieved. A theoretical background that illustrates the limitations with the ITC diode and a detailed presentation of...
A wide area and error free ultra high frequency (UHF) radio frequency identification (RFID) interrogation system based on the use of multiple antennas used in cooperation to provide high quality ubiquitous coverage, is presented. The system uses an intelligent distributed antenna system (DAS) whereby two or more spatially separated transmit and receive antenna pairs are used to allow greatly improved...
This paper presents a passive multistandard HF/ UHF-RFID-tag implemented in a 0.13μm bulk CMOS process. The RFID-tag consists of a multistandard HF/ UHF frontend for both frequency bands at 13.56 MHz and around 900 MHz. The tag is enhanced with additional functionality for sensing and localization. The integrated sensor interface consists of a multiplexer, a temperature sensor and an ultra-low power...
Multiple tags in Radio Frequency Identification (RFID) systems are scheduled by a medium access control layer using the Framed Slotted Aloha (FSA) or binary tree protocol. The focus of our research is on FSA and passive Ultra High Frequency (UHF) RFID. In current standards, only one tag can be acknowledged per slot. In this work we propose the increase of the theoretical throughput of FSA RFID systems...
RFID technology has been gaining popularity in several automated inventory management applications. In such applications, thousands of RFID tags are attached to different products and the reader(s) will be collecting tags IDs using an arbitration protocols. In the existing tag arbitration protocols, significant time and power are consumed on inevitable tag collisions. In this paper, collision time...
Radio Frequency Identification (RFID) technology become an important tool for items identification and tracking. In this paper we observe RFID Gen2 communication protocol between the RFID reader and the low-cost battery free passive RFID tags. To establish communication between the reader and tags, Gen2 uses Dynamic Frame Slotted ALOHA (DFSA) Medium Access Control (MAC) layer protocol with Q-Selection...
Physical objects often form a group such as objects in a shipping container. RFID enables us to identify each object and even the container itself. However, current RFID does not provide information on IDs missing from a group. This paper proposes a method to determine the unique IDs of objects missing from a group without any external database or verifier. The proposed method logically splits a group...
This work investigates three major phenomena of range estimation performance for a passive RFID system that transmits power-optimized waveforms (POWs). The shape of the POW, nonlinear charge pump reflections, and frequency-flat multipath environments are investigated. A maximum-likelihood (ML) range estimator analyzes the backscattered signal from a passive RFID tag that includes the POW as a carrier...
Options for RFID tag tracking and localization are an essential asset for future high performance RFID reader systems. A reader with long reading range, high reading rate and multi-tag capability should be able to assist the user to find / retrieve tags, to create spatial object maps and to restrict the reading range to specific regions of interest. In this paper we introduce a novel method for RFID...
The ability to accurately localize passive UHF RFID tags in uncontrolled and unstructured environments is limited by multipath propagation. Therefore, in order to increase the spatial resolution of RF based localization methods we propose to combine them with additional sensing capabilities. In this work we enhance passive UHF RFID tags with LEDs, using the Wireless Identification and Sensing Platform...
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