scholarly journals Low-cost wireless power efficiency optimization of the NFC tag through switchable receiver antenna – ERRATUM

2018 ◽  
Vol 5 (2) ◽  
pp. 113-113
2018 ◽  
Vol 5 (2) ◽  
pp. 87-96 ◽  
Author(s):  
Yi Zhao ◽  
Huaye Li ◽  
Saman Naderiparizi ◽  
Aaron Parks ◽  
Joshua R. Smith

Near-field communication (NFC) readers, ubiquitously embedded in smartphones and other infrastructures can wirelessly deliver mW-level power to NFC tags. Our previous work NFC-wireless identification and sensing platform (WISP) proves that the generated NFC signal from an NFC enabled phone can power a tag (NFC-WISP) with display and sensing capabilities in addition to identification. However, accurately aligning and placing the NFC tag's antenna to ensure the high power delivery efficiency and communication performance is very challenging for the users. In addition, the performance of the NFC tag is not only range and alignment sensitive but also is a function of its run-time load impedance. This makes the execution of power-hungry tasks on an NFC tag (like the NFC-WISP) very challenging. Therefore, we explore a low-cost tag antenna design to achieve higher power delivered to the load (PDL) by utilizing two different antenna configurations (2-coil/3-coil). The two types of antenna configurations can be used to dynamically adapt to the requirements of varied range, alignment and load impedance in real-time, therefore, we achieve continuous high PDL and reliable communication. With the proposed method, we can, for example, turn a semi-passive NFC-WISP into a passive display tag in which an embedded 2.7″ E-ink screen can be updated robustly by a tapped NFC reader (e.g. an NFC-enable cell-phone) over a 3 seconds and within 1.5cm range.


Proceedings ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 13
Author(s):  
Yixuan Sun ◽  
Stephen Beeby

This paper presents the COMSOL simulations of magnetically coupled resonant wireless power transfer (WPT), using simplified coil models for embroidered planar two-coil and four-coil systems. The power transmission of both systems is studied and compared by varying the separation, rotation angle and misalignment distance at resonance (5 MHz). The frequency splitting occurs at short separations from both the two-coil and four-coil systems, resulting in lower power transmission. Therefore, the systems are driven from 4 MHz to 6 MHz to analyze the impact of frequency splitting at close separations. The results show that both systems had a peak efficiency over 90% after tuning to the proper frequency to overcome the frequency splitting phenomenon at close separations below 10 cm. The four-coil design achieved higher power efficiency at separations over 10 cm. The power efficiency of both systems decreased linearly when the axial misalignment was over 4 cm or the misalignment angle between receiver and transmitter was over 45 degrees.


2019 ◽  
Vol 11 ◽  
pp. 175682931987005
Author(s):  
Jose Polo ◽  
Lluís Hontecillas ◽  
Ignacio Izquierdo ◽  
Oscar Casas

The aim of this work is to demonstrate the feasibility use of an Micro air vehicles (MAV) in order to power wirelessly an electric system, for example, a sensor network, using low-cost and open-source elements. To achieve this objective, an inductive system has been modelled and validated to power wirelessly a sensor node using a Crazyflie 2.0 as MAV. The design of the inductive system must be small and light enough to fulfil the requirements of the Crazyflie. An inductive model based on two resonant coils is presented. Several coils are defined to be tested using the most suitable resonant configuration. Measurements are performed to validate the model and to select the most suitable coil. While attempting to minimize the weight at transmitter’s side, on the receiver side it is intended to efficiently acquire and manage the power obtained from the transmitter. In order to prove its feasibility, a temperature sensor node is used as demonstrator. The experiment results show successfully energy transportation by MAV, and wireless power transfer for the resonant configuration, being able to completely charge the node battery and to power the temperature sensor.


Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1029 ◽  
Author(s):  
Guidong Zhang ◽  
Zuhong Ou ◽  
Lili Qu

A wireless power transmission (WPT) requires high switching frequency to achieve energy transmission; however, existing switching devices cannot satisfy the requirements of high-frequency switching, and the efficiency of current WPT is too low. Compared with the traditional power inductors and capacitors, fractional-order elements (FOEs) in WPT can realize necessary functions though requiring a lower switching frequency, which leads to a more favorable high-frequency switching performance with a higher efficiency. In this study, a generalized fractional-order WPT (FO-WPT) is established, followed by a comprehensive analysis on its WPT performance and power efficiency. Through extensive simulations of typical FO wireless power domino-resonators (FO-WPDRS), the functionality of the proposed FO-WPT for medium and long-range WPT is demonstrated. The numerical results show that the proposed FOE-based WPT solution has a higher power efficiency and lower switching frequency than conventional methods.


Telecom ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 96-113
Author(s):  
Pavlos Doanis ◽  
Achilles Boursianis ◽  
Julien Huillery ◽  
Arnaud Bréard ◽  
Yvan Duroc ◽  
...  

The technique of transmitting multi-tone signals in a radiative Wireless Power Transfer (WPT) system can significantly increase its end-to-end power efficiency. The optimization problem in this system is to tune the transmission according to the receiver rectenna’s nonlinear behavior and the Channel State Information (CSI). This is a non-convex problem that has been previously addressed by Sequential Convex Programming (SCP) algorithms. Nonetheless, SCP algorithms do not always attain globally optimal solutions. To this end, in this paper, we evaluate a set of Evolutionary Algorithms (EAs) with several characteristics. The performance of the optimized multi-tone transmission signals in a WPT system is assessed by means of numerical simulations, utilizing a simplified Single Input Single Output (SISO) model. From the model evaluation, we can deduce that EAs can be successfully applied to the waveform design optimization problem. Moreover, from the presented results, we can derive that EAs can obtain the optimal solutions in the tested cases.


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