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A passive position orientation measurement method is presented which leverages the spatial variation of the reflected magnetoquasistatic field from a mobile loop to determine the loop's spatial orientation. The azimuthal orientation was measured from 0° to 360° at a distance of 1 m from the fixed measurement loop. Inverting the theoretical expressions to estimate orientation from measured field values...
Recently, automated identification techniques that utilize radio frequency (RF) systems have experienced growth both in the industry and in research worldwide. The current state-of-art of this identification realm is the radio frequency identification (RFID) system, which utilizes a transponder with a unique identifier. RFID systems can be classified into active systems (with built-in power supply),...
In this paper, we present an analytical view of the maximum far-field tag gain of a typical commercially available passive UHF RFID tag design operating at 915 MHz, which is the center frequency of the Industrial, Science, and Medical (ISM) band. The far field gain is calculated using FEKO 5.3 designed by EMSS, which is a computational electromagnetic (CEM) tool, and the method used here includes...
In this paper, we present a novel application of NRM's in passive UHF radio frequency identification (RFID) tag inlay (substrate). The passive RFID tag is typically manufactured to consist of an antenna and an asynchronous integrated circuit (ASIC) chip, as well as connection pads on a PET substrate. Here, we propose an implementation as depicted, where the substrate is a NRM. In an attempt to predict...
In this paper, the passive UHF RFID tag is characterized on a metal slab for varying distances. The bent dipole tag designed by UPM Raflatac Corporation and the Squiggle tag designed by Alien Corporation is tested for electromagnetic strength of the reply signal. These tags are also simulated in FEKO 5.3 designed by EMSS to depict their performances on the metal slab for varying distances, and is...
In this paper, the utility of flare structures in metal pipes are introduced as a mechanism to increase the performance of passive UHF RFID tags operating within these metallic structures. These performance enhancements are noted to exist predominantly in the tag gain, which is a fundamental factor determining RFID tag readability. Theory is presented to describe in detail the design requirements...
In this paper, we describe the specific absorption rates for RF propagation in muscle tissues and present an evaluative study for radiation reflected by a passive UHF radio frequency identification (RFID) tag. A derivation of UHF RFID tag backscatter theory is presented. This theory is merged with the biological effects of RF propagation in muscle tissues to form a general theory. This general theory...
An analysis of surface currents and charges, as well as wire current variations in passive UHF RFID tags are presented to illuminate differences in tag antenna designs. Surface and wire current or charge distributions are known to be important parameters in distinguishing the radiation pattern of passive tags in the far field, and has been shown recently to have severe consequences on directivity...
In this paper, we present a novel real-time localization system (RTLS) based upon 2.45 GHZ surface acoustic wave (SAW) radio frequency identification (RFID) systems. The system utilizes a novel localization method that combines the angular rotation of the RFID readerspsila antenna or read beam with the inherent time-of-flight (TOF) distance measurement capabilities using a csc2 thetas pattern for...
In this paper, we present an experimental study on the SAR of the human head in an environment with a typical RFID reader system. The results predict that 2 RFID reader antennas at distances of 10 cm from the human head operating additively, will contribute to a SAR in the human head of up to a maximum of 2.02763 W/kg, which is above the limit for safe exposure of RF radiation as allowed by FCC is...
In this paper we extend the theory of radio frequency (RF) propagation within helical and toroidal metal pipes. This work is motivated by the need to understand the operation of UHF radio frequency identification (RFID) systems when the tags are placed within toroidal metal pipes. The field components inside a helical metal pipe are derived to obtain the propagation and attenuation constants and the...
In this paper, we identify the most significant problems involving the impacts of radio frequency (RF) radiation on the human body. The coming pervasive healthcare environment will rely heavily upon wirelessly communicating devices to provide the information visibility and communication capabilities required to achieve these ambitious systems. The impact of significant and continuous RF radiation...
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