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关键词： RFID   Drip Rate Monitoring   Tag Pair   Millimeter-level Sensing  

摘要： As an important indicator of the infusion monitoring for clinical treatment, the drip rate is expected to be monitored in an accurate and real-time manner. However, state-of-the-art drip rate monitoring schemes either suffer from high maintenance or incur high hardware cost. In this paper, we propose DropMonitor, an RFID-based approach to perform the mm-level sensing for infusion drip rate monitoring. By attaching a pair of batteryless RFID tags on the drip chamber, we can estimate the drip rate by capturing the RF-signals reflected from the vibrating liquid surface caused by the falling droplets. Particularly, we use the sensing tag to perceive the liquid surface vibration in the drip chamber and further derive the drip rate for infusion monitoring. Moreover, to sufficiently mitigate the multi-path interference from the surrounding human activities, we use the reference tag to perceive the multi-path signals from the indoor environment. By computing the difference of RF-signals from tag pairs, we cancel the multi-path interference and extract the drip-rate-related signals. We have implemented a prototype system and evaluated its performance in real applications. The experiment results show that DropMonitor can accurately estimate the infusion drip rate, and the average relative error of drip rate estimation is below 1% for conventional cases. In this way, considering the essential sampling rates of each tag, DropMonitor is able to monitor the drip rate for over a dozen of infusion bottles/bags in parallel with one COTS RFID system.

摘要： Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

关键词： Cross-frequency communication   harmonic backscatter   RFID   WiFi  

摘要： Recent advances in Cross-Technology Communication (CTC) have improved efficient cooperation among heterogeneous wireless devices. To date, however, even the most effective CTC systems require these devices to operate in the same ISM band (e.g., 2.4GHz) because of the conventional wisdom that wireless transceivers with different (fundamental) frequencies cannot communicate with one another. Our work, which is called TiFi, challenges this belief by allowing a 2.4GHz WiFi receiver (e.g., a smartphone) to identify UHF RFID tags, which operate at the spectrum between 840 similar to 920MHz. TiFi does not require changing current smartphones or tags. Instead, it leverages the underlying harmonic backscattering of tags to open a second channel and uses it to communicate with WiFi receivers. We design and implement TiFi with commodity WiFi chipsets (e.g., Broadcom BCM43xx, Murata KM6D280 40, and Qualcomm WCN3990). Our comprehensive evaluation shows that TiFi allows WiFi receivers to identify UHF RFID tags within the range of 2 m and with a median goodput of 95%, which is comparable to today's mobile RFID readers.

关键词： Ceramic resonators   dielectric resonant antennas (DRAs)   radio frequency identification (RFID)  

摘要： Radio frequency identification (RFID) is a mature technology that allows contactless reading of data via a wireless communication link. While communication protocols in this field are subject to international regulations, there are plenty of opportunities to improve hardware realization of antenna devices that support this technology. In particular, readout range extension and miniaturization of passive RFID tags is an important challenge with far-reaching goals. Here, we introduce and analyze a new concept of high-permittivity ceramic tag that relies on different physical principles. Instead of using conduction currents in metallic wires to drive electronic chips and generate electromagnetic radiation, high-permittivity components rely on excitation of displacement currents. Those are efficiently converted to actual electric current which drives the memory chip. Practical aspects of this approach are improved robustness to environmental fluctuations, footprint reduction, and readout range extension. In particular, our high-permittivity ceramic (epsilon similar to 100) elements have demonstrated a 25% reading range improvement in comparison to commercial tags. In case when state-of-the-art readers and RFID chips are used, the readout distances of the developed ceramic tags can reach 22 m. This number can be further extended with improved matching circuits. Miniature RFID tags, capable to establish long-range communication channels, can find use in many applications, including retail, security, Internet of Things, and many others.

关键词： Wireless   Environmentally friendly   Conductive ink   Transparent ink   RFID Antenna   Printed electronics  

摘要： Wireless communication employing radio-frequency identification (RFID) tags is progressively more widespread in a variety of industrial and commercial sectors. Aspects as demanding specific needs regarding reading distance, production cost, and processability are requested for commercial applications. Nowadays, printing of optical barcodes is the most economically technology for short distance (up to similar to 30 cm) reading applications. However, the large-scale and low-cost printing of RFID tags would be a competitive alternative to barcode technology because it allows quicker identification with much less reading errors. Here we demonstrate a semi-transparent, screen printed RFID antennas using a non-metallic and environmentally friendly conductive paste. The variation of the film thickness (from 2.5 up to 15 mu m) permitted the fabrication of antennas with reading range (0.84-3.29 m), sheet resistance (6.2-36 Omega/sq), and optical transmittance (0-32.3%), which are compatible to commercial or industrial applications aiming short to moderate reading distances.

关键词： Phase   RFID   tracking   trajectory  

摘要： In this article we propose a novel method for tracking a moving UHF RFID tag in 3D space. The tag moves in an area monitored by at least two antennas fixed at known locations. Phase measurements from each antenna are collected. Assuming a grid of N initial positions, we calculate N possible trajectories, by deriving closed form expressions, exploiting only the phase measurements collected by each antenna separately. Then, using the measured phase-difference from each antenna-pair, a hyperbola's branch on which the tag must be located is calculated. We evaluate the distance of each trajectory from the hyperbolas. Finally, we select the trajectory that minimizes the distance. Experimental results, conducted with a SLAM (Simultaneous Localization and Mapping)-enabled robot show a mean error less than 20cm with estimations derived in the order of ms. Compared to prior art, the proposed method does not assume neither knowledge of the trace, nor of the initial position of the tag. Furthermore, it accomplishes high accuracy at reduced computation time.

关键词： observation hive   RFID   camera recording   honeybee   foraging and communication  

摘要： A typical honeybee colony contains more than 15,000 individuals, each with its own task related to supporting the hive and maintaining the colony. In previous studies on honeybees, observing individual animals' behaviors has been a difficult and time-consuming task to understand the relationship between in-hive communication and environmental changes outside the hive, therefore it is necessary in any attempt to develop applying a remote sensing technology. To allow researchers to pass much of this tracking work on to computers, we have developed the lifelog monitoring system for honeybees, which uses RFID and Raspberry Pi camera recordings. Our preliminary experiments consisted of several tests aimed at identifying the optimal conditions for this system. First, two commercial RFID readers with antennas were compared in terms of their sensitivity to signals from RFID tags placed at various distances. We found that the UP16-1000-J2 reader was much more sensitive and had a longer effective range compared to the UP4-200-J2. The most sensitive region in the RFID antenna on the UP16-1000-J2 reader was 30 mm long and 5 mm wide at its center. Based on this preliminary information, we designed and built a passage from the interior of the observation hive to the outside so that all RFID-tagged bees could be detected individually by the RFID reader as they walked through the passage. Moreover, to detect the direction of either departure or arrival of each bee, we placed two RFID antennas under the passage between the observation hive and the outside, one near each end of the passage. All departure and arrival times of RFID-tagged bees were detected with their ID numbers. Using recorded data from these two RFID readers, we could measure how much time each tagged bee spent outside the hive. In addition to RFID recording on the passage, we also tracked all in-hive movements of numbered RFID-tagged honeybees. In-hive movements were simultaneously, comprehensively and automatically

关键词： RFID   propagation   international space station   epidermal antennas   telemetry   path loss  

摘要： The monitoring of Astronaut's health is one of the most impacting aspects of long-duration Space missions, especially for the high involvement required to the crew members in the daily acquisition of body parameters. Automatic procedures based on wireless systems would grant undeniable benefits, especially if lightweight and battery-less devices could be adopted. The possibility and the reliability of a communication link inside the International Space Station (ISS) is here investigated when the UHF-RFID epidermal technology is adopted. A Ray Tracing asymptotic method is hence proposed to evaluate the coverage area and the read probability inside the Harmony module. The analysis is referred to up to two astronauts simultaneously present in the module and to the presence of multiple reader antennas, in case purely passive epidermal tags are adopted. Simulations revealed that it is possible to identify some simple operating conditions that allow to obtain a reliable RFID link, also thanks to the advantageous propagation characteristics of the module itself.

关键词： Circularly polarized   CPW-fed   handheld reader   UHF RFID  

摘要： This paper presents a new coplanar waveguide (CPW)-fed circularly polarized square slot antenna (CPSSA). The proposed antenna uses an inverted Z-shaped feedline protruded from the signal line of the feeding CPW. Circularly polarized (CP) radiation can be achieved by adequately inserting the arc-shaped grounded strip into the upper right corner of the square slot. The widened vertical tuning stub on the L-shaped grounded strip can improve impedance matching and axial ratio (AR) performance. The measured results indicate that the 10 dB impedance bandwidth is 620 MHz (652-1272 MHz), and the 3 dB axial ratio bandwidth is 320 MHz (840-1160 MHz), which has a broadband characteristic. In the range of the universal UHF RFID band, the measured peak gain is about 4.4 dBi. The proposed CPSSA uses low-cost FR4 material as the dielectric substrate. The overall size of the antenna is 119 x 119 x 0.5 mm(3). The proposed antenna has a simple structure, easy processing, good performance, wide operating bandwidth, and dual circular polarization characteristic. It can be applied to the universal UHF RFID handheld reader environment.

关键词： Car2Car communications   V2X   automotive radar   FMCW radar   backscatter   RFID  

摘要： This work proposes the use of a modulated tag for direct communication between two vehicles using as a carrier the wave emitted by an FMCW radar installed in the vehicle for advanced driver assistance. The system allows for real-time signals detection and classification, such as stop signal, turn signals and emergency lights, adding redundancy to computer video sensors and without incorporating additional communication systems. A proof-of-concept tag has been designed at the microwave frequency of 24 GHz, consisting of an amplifier connected between receiving and transmitting antennas. The modulation is performed by switching the power supply of the amplifier. The tag is installed on the rear of the car and it answers when it is illuminated by the radar by modulating the backscattered field. The information is encoded in the modulation switching rate used. Simulated and experimental results are given showing the feasibility of the proposed solution.