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A numerical analysis on the Wireless Power Transfer (WPT) efficiency for Near-field (NF) Ultra High Frequency UHF) Radio Frequency Identification (RFID) printer encoders is here proposed Specifically, it is shown that the selection of a particular reader antenna layout can significantly improve the system performance in terms of power transfer efficiency and spatial selectivity.
This paper deals with the analysis of different parameters to characterize the behavior of reader antennas for near-field UHF RFID systems. When dealing with near-field applications, the classical antenna parameters as radiation pattern, input impedance matching, etc., are not useful. The design of reader antennas for these near-field applications require the use of other parameter that provide information...
A low-profile and compact 3D antenna operating at LTE, GSM and UMTS frequency bands (790–2690 MHz) is proposed for a vehicular 2×2 MIMO system. The performance of the single 3D radiating element is here analyzed. Then, the two-antenna system performance is analyzed in terms of impedance matching, isolation and envelope correlation coefficient, highlighting the effect of some geometrical parameters...
This paper presents a localization system for objects tagged with UHF-RFID passive tags, where the reader is attached to a drone. The system implements the phase-based SARFID technique to locate static tags with respect to a UHF-RFID reader attached to a commercial drone. The reader antenna trajectory is achieved through a Global Positioning System. The bi-dimensional tag position is estimated with...
This paper presents a new technique to locate a device moving along a known trajectory, when it is equipped with an UHF RFID reader. The proposed technique exploits the phase of consecutive readings of a single stationary tag positioned near the device trajectory, within the reader coverage area. To increase the length of the monitored path where the reader can be effectively localized, the localization...
The application of Artificial Neural Networks (ANNs) to discriminate tag actions in UHF-RFID gate is presented in this paper. By exploiting Received Signal Strength Indicator values acquired in a real experimental scenario, a multi-layer perceptron neural network is trained to distinguish among tags incoming, outgoing or passing the RFID gate. A 99% accuracy can be obtained in tag classification by...
A novel compact 3D antenna operating at LTE, GSM and UMTS frequency bands (790–2690 MHz) is proposed for vehicular applications. The antenna consists of a metal-sheet properly cut and shaped to fit an overall volume of 50×50×30 mm3. A Planar Inverted-F Antenna is designed to cover the lower frequency band (below 1GHz), while an integrated folded monopole adds higher frequency resonances. An elliptical-shape...
An antenna design criterion based on the simulated distribution of electric and magnetic energy densities has been proposed to improve the robustness of wearable antennas. A flexible tag characterization and performance evaluation platform is here used to assess the effectiveness of this theoretical approach. Specifically, the analysis has been carried out by considering a single layer UHF RFID tag...
Two low-profile and compact 3D antennas operating at LTE, GSM and UMTS frequency bands (790-2690 MHz) are here numerically analyzed for a vehicular MIMO system. After an analysis of the single element performance, two identical 3D antennas are considered. A preliminary numerical analysis on the effect of geometrical parameters such as inter-element distance and reciprocal orientation have been discussed...
An experimental approach is proposed to validate the theoretical energy-based considerations for wearable UHF RFID antenna design. On the basis of numerical analysis, it has been shown that wearable antennas presenting an energy density peak far from the antenna border are more robust with respect to the distance from the human body. A flexible and cost-effective RFID tag characterization and performance...
This paper presents a multi-facet design of an array antenna for near-field focused applications. The cylindrical arrangement of a set of antenna panels (namely, focused linear arrays) will radiate fields focused at the center of the circle formed by the panels. Such an array configuration exhibits superior performance with respect to the conventional planar arrangement, if a symmetric focus region...
In the framework of Near-field (NF) UHF-RFID applications, a large number of ad-hoc antennas have been proposed in the last decade. In particular, the authors recently proposed novel reconfigurable antenna configurations, the so-called Modular Antennas. In these layouts, a travelling wave antenna is combined with a low-gain resonating antenna, which share the surface of the desktop reader antenna...
In this paper, a review on near-field focused (NFF) antennas for short-range wireless links at the microwave frequency band is presented. The basic working principles, the design guidelines, as well as the synthesis procedures suggested for the near-field shaping around the focal point, will be addressed. The review will also span on the different technologies used to implement NFF antennas at the...
A number of wearable antennas suitable for implementation of UHF-RFID tags have been presented in the open scientific literature. All of them are characterized by a high sensitivity with respect to the coupling with the human body, both on the input matching and on the antenna efficiency. This work presents a numerical investigation performed over a couple of wearable, ungrounded, antennas configurations,...
A novel ultra wideband antenna is here proposed for Vehicle to Infrastructure (V2I) communication systems. Two Vivaldi antennas are arranged in a back-to-back configuration (array of two Vivaldi antennas) to radiate both in front and rear car driving direction. By feeding the antennas with out-of-phase currents, the field radiation in the transversal direction is attenuated, so limiting the multipath...
The robustness of wearable UHF-band grounded antennas with respect to body-coupling effects is addressed through numerical investigations. Main goal is gaining physical insights on the relationship between the grounded antenna performance and the distribution of the electric and magnetic energy densities in the antenna near-field region close to the ground plane border. Two UHF Planar Inverted-F Antennas...
A back-to-back Vivaldi Antenna is here proposed for a novel Vehicle to Infrastructure (V2I) communication system in the X-band (8.5–11GHz). The antenna has to be compact and low-profile in order to be installed on the car's roof. To cover the entire operating band, an ultra wideband (UWB) Vivaldi antenna has been chosen. Since the antenna has to radiate both in front and rear car driving direction,...
A novel configuration of a Modular Antenna proposed for NF UHF-RFID desktop reader applications is here described. Specifically, a spiral Travelling Wave Antenna (TWA) is used to generate a strong and uniform field in proximity of the antenna surface. Then, such a microstrip transmission line feeds four resonating curved slot antennas placed close to the spiral TWA and 90-degree rotated with respect...
A printer-encoder antenna has to reliably communicate with only one targeted tag among a number of tightly spaced transponders in very close proximity. Moreover, the distance between the encoder and transponder antennas is typically a few millimeters only. Thus, antennas for UHF-RFID printer encoders are more similar to electromagnetic couplers than to antennas, and a specific analysis is required...
The robustness of wearable UHF-band planar inverted-F antennas (PIFAs), with respect to body–antenna separation and human tissue dispersion, is addressed through numerical investigations. The main goal is gaining physical insights into the relationship between the grounded antenna performance and the distribution of the electric and magnetic energy densities in the antenna near-field region close...
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