Current and Future Trends of RFID Systems: Guest Editorial of the Special Issue on SpliTech 2021 and IEEE RFID-TA 2021 Conferences

This year, the IEEE Journal of Radio Frequency Identification (JRFID), decided to host a joint Special Issue collecting extended versions of papers coming from two international events. The former is the IEEE International Conference on RFID Technology and Applications (RFID-TA) 2021, virtually held in Delhi, India, on October 6-8, 2021. The latter is the International Symposium on Advances in RFID Technology organized within the International Conference on Smart and Sustainable Technologies (SpliTech), hosted in Split and Bol, Croatia, on September 8-11, 2021. SpliTech was technically co-sponsored by the IEEE and technically media sponsored by the IEEE Council on RFID (CRFID)

Compact 3-D-Printed Circularly Polarized Antenna for Handheld UHF RFID Readers

In this letter, the aptness of the combination of three-dimensional (3-D) printing and radio frequency identification (RFID) is faced by presenting a compact, low-profile, and cost-effective circularly polarized antenna for handheld UHF RFID reader. The radiating element has been realized through a circular array of four inverted-F monopoles, where the array elements are excited with a 90° phase offset through a microstrip feeding network, realized in 3-D printing technology as well. Taking advantage from low losses and moldability of the 3-D printing materials joint to a specific design strategy, the proposed antenna realizes an improved gain and an appreciable size reduction if compared with the state of the art

Smart Prototyping Techniques for UHF RFID Tags: Electromagnetic Characterization and Comparison with Traditional Approaches

Over the last few years, the active and growing interest in Radiofrequency Identification (RFID) technology has stimulated a conspicuous research activity involving design and realization of passive label-type UHF RFID tags customized for specific applications. In most of the literature, presented and discussed tags are prototyped by using either rough-and-ready procedures or photolithography techniques on rigid Printed Circuit Boards. However, for several reasons, such approaches are not the most recommended, in particular they are rather time-consuming and, moreover, they give rise to low quality devices in one case, and to cumbersome and rigid tags in the other. In this work, two alternative prototyping techniques suitable for cost-effective, time-saving and high-performance built-in-lab tags are introduced and discussed. The former is based on the joint use of flexible PCBs and solid ink printers. The latter makes use of a cutting plotter to precisely shape the tag antenna on thin copper sheets. Afterwards, a selection of tags, designed and manufactured by using both traditional and alternative techniques, is rigorously characterized from the electromagnetic point of view in terms of input impedance and whole tag sensitivity by means of appropriate measurement setups. Results are then compared, thus guiding the tag designer towards the most appropriate technique on the basis of specific needs

Design of Passive RFID Sensor Tags Enhanced by a Novel Logical Communication Procedure over LLRP

Over the past decade, electromagnetic and communication science societies, along with improving the classical RFID technology, have put in a great deal of effort in designing novel and more complex UHF RFID tags with augmented capabilities. Novel tags offer additional functionalities besides identification by embedding sensors, actuators, and processing units. In this work an enhanced version of one of such devices, called SPARTACUS, is presented. While being completely passive, it conjugates identification, sensing, local computing, and actuation control and enables a proactive communication with any standard RFID reader. The paper presents details on a novel logical communication procedure over Low Level Reader Protocol (LLRP), besides discussing system validation and performance evaluation

Enabling Self-Powered Autonomous Wireless Sensors with New-Generation I2C-RFID Chips

A self-powered autonomous RFID device with sensing and computing capabilities is presented in this paper. Powered by an RF energy-harvesting circuit enhanced by a DC-DC voltage booster in silicon-on-insulator (SOI) technology, the device relies on a microcontroller and a new generation I2C-RFID chip to wirelessly deliver sensor data to standard RFID EPC Class-1 Generation-2 (Gen2) readers. When the RF power received from the interrogating reader is -14 dBm or higher, the device, fabricated on an FR4 substrate using low-cost discrete components, is able to produce 2.4-V DC voltage to power its circuitry. The experimental results demonstrate the effectiveness of the device to perform reliable sensor data transmissions up to 5 meters in fully-passive mode. To the best of our knowledge, this represents the longest read range ever reported for passive UHF RFID sensors compliant with the EPC Gen2 standard

Dielectric resonators antennas potential unleashed by 3D printing technology: A practical application in the IoT framework

One of the most promising and exciting research fields of the last decade is that of 3D-printed antennas, as proven by the increasing number of related scientific papers. More specifically, the most common and cost-effective 3D printing technologies, which have become more and more widespread in recent years, are particularly suitable for the development of dielectric resonator antennas (DRAs), which are very interesting types of antennas exhibiting good gain, excellent efficiency, and potentially very small size. After a brief survey on how additive manufacturing (AM) can be used in 3D printing of antennas and how much the manufacturing process of DRAs can benefit from those technologies, a specific example, consisting of a wideband antenna operating at 2.4 GHz and 3.8 GHz, was deeply analyzed, realized, and tested. The obtained prototype exhibited compact size (60 × 60 × 16 mm3, considering the whole antenna) and a good agreement between measured and simulated S11, with a fractional bandwidth of 46%. Simulated gain and efficiency were also quite good, with values of 5.45 dBi and 6.38 dBi for the gain and 91% and 90% for the efficiency, respectively, at 2.45 GHz and 3.6 GHz

On the use of passive UHF RFID tags in the pharmaceutical supply chain: a novel enhanced tag versus high-performance commercial tags

Item-level RFID-based tracing systems are of growing interest both from industrial and scientific standpoints. In such a context, the choice of the most adequate RFID tag, in terms of shape, frequency, size and reading range, is crucial. The potential presence of items containing materials hostile to the electromagnetic propagation exacerbates the problem. In addition, the peculiarities of the different RFID-based checkpoints make the requirements for the tag even more stringent. In this work, the performance of several commercial UHF RFID tags in each step of the pharmaceutical supply chain has been evaluated, confirming the foreseen criticality. On such basis, a guideline for the electromagnetic design of new high-performance tags capable of overcoming such criticalities has been defined. Finally, driven by such guidelines, a new enhanced tag has been designed, realised and tested, demonstrating that high performance item-level tracing systems can actually be implemented also in critical operating conditions. Copyright © 2013 Inderscience Enterprises Ltd

Inertially-Controlled Two-dimensional Phased Arrays by Exploiting Artificial Neural Networks and Ultra-Low-Power AI-based Microcontrollers

The use of Artificial Intelligence (AI) in electronics and electromagnetics is opening many attractive research opportunities related to the smart control of phased arrays. This is particularly challenging especially in some high-mobility contexts, such as drones, 5G, automotive, where the response time is crucial. In this paper a novel method combining AI with mathematical models and firmware for orientation estimation is proposed. The goal is to control two-dimensional phased arrays using an Inertial Measurement Unit (IMU) by exploiting a feed-forward neural network. The neural network takes the IMU-based beam direction as input and returns the related phase shift matrix. To make the method computationally efficient, the network structure is carefully chosen. Specific and discretized cross-section regions of the array factor (AF) main lobe are considered to compute the phase shift matrices, used in turn to train the neural network. This approach achieves a balance between the number of phase-shifting processes and spatial resolution. Without loss of generality, the proposed method has been tested and verified on 4× 4 and 6× 6 arrays of 2.4 GHz antennas. The obtained results demonstrate that reconfigurability time, easiness of use, and scalability are suitable for a wide range of high-mobility applications

Electromagnetic analysis and performance comparison of fully 3D-printed antennas

In this work, the possibility of directly prototyping antennas by exploiting additive manufacturing 3D-printing technology is investigated. In particular, the availability of printable filaments with interesting conductive properties allows for printing of even the antenna conductive elements. Three samples of a 2.45 GHz microstrip patch antenna have been 3D-printed by using different approaches and materials, and their performance evaluated and compared. In particular, the same dielectric substrate printed in polylactic acid (PLA) has been adopted in all cases, whilst copper tape and two different conductive filaments have been used to realize the conductive parts of the three antenna samples, respectively. Even if an expected radiation efficiency reduction has been observed for the conductive filament case, the comparative analysis clearly demonstrates that 3D-printing technology can be exploited to design working fully-printed antennas, including the conductive parts