UWB RFID Research Articles

A sensor technology to continuously monitor changes in cognition

AbstractBackgroundResearchers are increasingly utilizing real‐time sensors with ultra‐wideband radio frequency identification device (UWB RFID) technology to continuously, automatically and unobtrusively track the behavior and movement of older adults across care settings (Bowen, Kearns, Crenshaw, & Stanhope, 2019; Bowen & Rowe, 2019; Bowen & Rowe, 2016). These systems can be integrated into the health care environment and are ecologically valid measures taken concurrently as adults perform everyday activities of daily living (ADL). The purpose of this study is to examine the use of a UWB RFID system for the early recognition of behaviors associated with cognitive decline among skilled nursing residents (N=23) of two health care facilities.MethodResidents were assessed continuously for an average of 10 months (SD=32.16 weeks). Scoring algorithms from the UWB RFID system utilized 1663 data points developed from x, y coordinates to measure the number and distance (meters) of continuous walking activity in a path. A path is defined as at least 60 seconds of walking and ends with a 30‐second stop. Cognitive function was measured by the Montreal Cognitive Assessment (Nasreddine, et al., 2005) and the Physical and Cognitive Performance Test (Bowen, Rowe, Ersek, Ibrahim, & Shea, 2017).ResultOn average, residents walked 1522.8 meters/week (SD=1572.7) with an average of 23.2 paths/week (SD=25.6). In multilevel models, accounting for ADL ability, an increased average number of paths per week was associated with decreased cognitive functioning (β= ‐0.65; p≤0.01).ConclusionContinuous walking in a path may be an early indicator of cognitive decline. Using an UWB RFID system may aid in the early detection and recognition of cognitive changes in this patient population. Importantly, these changes are also associated with other health events (e.g., falls, delirium, urinary tract infection, hospitalization) that may be ameliorable to intervention.

Compact dual polarized aperture coupled microstrip patch antenna for UWB RFID applications

Compact dual polarized aperture coupled microstrip patch antenna for UWB RFID applications

Fast diagnosis of type 1 neurofibromatosis

This chapter presents the implementation of some wireless sensors with the semi-passive time-coded UWB RFID systems presented in Chapter 4. Four implementations are presented:–a temperature sensor using the analog semi-passive UWB RFID system, using a PIN diode at the end of the transmission line, and powered by solar energy;–a nitrogen dioxide (NO2) gas sensor using carbon nanotubes (CNTs). It is integrated on the analog semi-passive UWB RFID system, with the backscatterer based on the RF switch;–a multi-sensor tag using the microcontroller-based semi-passive UWB RFID system, intended for smart city applications, and capable of measuring;-temperature,-humidity,-acceleration,-barometric pressure;–a second nitrogen dioxide (NO2) gas sensor, connected to the microcontroller-based semi-passive UWB RFID system, which digitizes the CNT resistance.

Wireless Concrete Mixture Composition Sensor Based on Time-Coded UWB RFID

This work presents a non-destructive wireless, concrete quality sensor based on chipless ultra-wideband radio frequency identification. The sensor is based on detecting the delay between two scattering modes induced by permittivity changes in the concrete. Theoretical, simulated and measured results with several embedded tags in samples are shown. The composition of the concrete blocks is remotely detected and classified.

Solar powered wireless temperature sensor based on UWB RFID with self-calibration

Solar powered wireless temperature sensor based on UWB RFID with self-calibration

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.

A Tracking Algorithm for Blind Navigation Based on Robust H Infinity Filter

This paper presents an algorithm for blind and visually impaired people to track their location. A precise positioning system utilizes UWB RFID tags for localization to mark points of interest. Given the joint estimation of TOA and DOA from blind person to station, a robust algorithm based on the extended filter is presented to accurately estimate their current location and moving velocity. This method is effective to the no-Gaussian or biased system model with unknown or not fully known observation error statistics.

Design of Chipless UWB RFID System Using A CPW Multi-Resonator

In this paper, the design of a novel chipless ultra-wideband radio-frequency identification (UWB RFID) system is proposed. The system employs printable uniplanar chipless tags and a pair of high-gain reader antennas. The chipless tag is composed of two UWB monopole antennas, connected by a coplanar waveguide (CPW). The tag's ID is represented by a spectral signature in the UWB frequency range, and is created by a multi-resonator embedded on the coplanar waveguide. The detection of the tag's ID is based on using only the amplitude of the spectral signature, which significantly simplifies the complexity of detection. The reader employs two separate Vivaldi antennas - one for transmitting a vertically polarized signal, and the other for receiving a horizontally polarized signal - to reduce the mutual coupling between the uplink and downlink signals. Further reduction of mutual coupling is achieved by using a copper plate at the reader to separate the uplink and downlink signals. These two proposed methods together reduced the mutual coupling by 20 dB. The chipless RFID tag with eight coplanar waveguide resonators in a group and the reader antennas were designed using computer simulation, and fabricated on Rogers substrates for measurement. The results of studies in an anechoic chamber showed that the proposed UWB RFID system could achieve a reading range of larger than 30 cm, at least three times longer than the maximum distance of a similar system reported by others. This indicated that the proposed system has great potential for short-range item tracking at low cost.