Research

12 pages, 327 KiB

Open AccessArticle

High-Efficiency Power Optimization Based on Reconfigurable Intelligent Surface for Nonlinear SWIPT System

by Hongxia Zheng, Xingquan Li, Chunlong He and Yatao Yang

Electronics 2022, 11(17), 2681; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics11172681 - 26 Aug 2022

Viewed by 1125

This paper presents an investigation of the transmitting power consumption of a base station (BS) in a simultaneous wireless information and power transfer (SWIPT) system enhanced by a reconfigurable intelligent surface (RIS). The aim is to optimize the total transmitting power consumption when [...] Read more.

This paper presents an investigation of the transmitting power consumption of a base station (BS) in a simultaneous wireless information and power transfer (SWIPT) system enhanced by a reconfigurable intelligent surface (RIS). The aim is to optimize the total transmitting power consumption when sending information signals and energy from the BS to ground sensors. To this end, the transmitting power consumption of the BS is optimized by satisfying the sensor’s minimum signal-to-interference-plus-noise ratio (SINR), the phase shift constraints of the RIS, and each sensor’s power-splitting (PS) ratio. In order to decouple the optimization variables, we use the technique of block coordinate descent (BCD) to transform the total problem into subproblems. In the second subproblem, the unit modulus constraints are approximated using the successive convex approximation (SCA) method, allowing the optimal solutions to be obtained by solving subproblems in an iterative manner. Our numerical simulation results show that transmitting power consumption can be significantly decreased by adding RIS to an SPWIT system, even in nonlinear harvest models of real application scenarios. Full article

(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design, Volume II)

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33 pages, 30421 KiB

Open AccessArticle

A Self-Powered UHF Passive Tag for Biomedical Temperature Monitoring

by Gregorio Zamora-Mejia, Jaime Martinez-Castillo, Alejandro Diaz-Sanchez, Jose M. Rocha-Perez, Agustín L. Herrera-May, Uriel G. Zapata-Rodriguez and Victor H. Carbajal-Gomez

Electronics 2022, 11(7), 1108; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics11071108 - 31 Mar 2022

Cited by 1 | Viewed by 1776

Abstract

Self-powered RF passive sensors have potential application in temperature measurements of patients with health problems. Herein, this work presents the design and implementation of a self-powered UHF passive tag prototype for biomedical temperature monitoring. The proposed battery-free sensor is composed of three basic [...] Read more.

Self-powered RF passive sensors have potential application in temperature measurements of patients with health problems. Herein, this work presents the design and implementation of a self-powered UHF passive tag prototype for biomedical temperature monitoring. The proposed battery-free sensor is composed of three basic building blocks: a high-frequency section, a micro-power management stage, and a temperature sensor. This passive temperature sensor uses an 860 MHz to 960 MHz RF carrier and a 1 W Effective Isotropic Radiated Power (EIRP) to harvest energy for its operation, showing a read range of 9.5 m with a 13.75 µW power consumption, and an overall power consumption efficiency of 10.92% was achieved. The proposed device can measure temperature variations between 0 °C and 60 °C with a sensitivity of 823.29 Hz/°C and a standard error of 13.67 Hz/°C over linear regression. Circuit functionality was validated by means of post-layout simulations, characterization, and measurements of the manufactured prototype. The chip prototype was fabricated using a 0.18 µm CMOS standard technology with a silicon area consumption of 1065 µm × 560 µm. The overall size of the self-powered passive tag is 8 cm × 2 cm, including both chip and antenna. The self-powered tag prototype could be employed for human body temperature monitoring. Full article

(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design, Volume II)

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9 pages, 54137 KiB

Open AccessArticle

Dual-Polarized Dipole Antenna for Wireless Data and Microwave Power Transfer

by Liangbing Liao, Zhiyi Li, Yuzhu Tang and Xing Chen

Electronics 2022, 11(5), 778; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics11050778 - 03 Mar 2022

Cited by 2 | Viewed by 5142

Abstract

This manuscript presents a broadband high-efficiency dual-polarized dipole antenna for wireless power and data transfer. The proposed antenna mainly consists of cross-dipole patches, matching baluns, and a ground plane. The dual-polarized radiation mode was achieved by using two linear-polarization matching baluns to feed [...] Read more.

This manuscript presents a broadband high-efficiency dual-polarized dipole antenna for wireless power and data transfer. The proposed antenna mainly consists of cross-dipole patches, matching baluns, and a ground plane. The dual-polarized radiation mode was achieved by using two linear-polarization matching baluns to feed the cross-dipole patches orthogonally. The proposed dual-polarized dipole antenna realizes a bandwidth with S₁₁ less than −10 dB (4.28 GHz–5.92 GHz) and a high radiation efficiency of about 95%. An independent rectifying circuit was designed, and a microwave energy transmission experiment was carried out. The final measured conversion efficiency for the two polarized ports at 5.8 GHz was about 77.6% and 76.4%, respectively. Simulation and measurement results showed that the proposed antenna is suitable for both wireless power and wireless data transfer applications. Full article

(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design, Volume II)

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18 pages, 5530 KiB

Open AccessArticle

Package-Scale Galvanic Isolators Based on Radio Frequency Coupling: Micro–Antenna Design

by Simone Spataro, Nunzio Spina and Egidio Ragonese

Electronics 2022, 11(3), 291; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics11030291 - 18 Jan 2022

Cited by 4 | Viewed by 1820

Abstract

This paper presents the design of on-chip micro-antennas for package-scale galvanic isolators based on RF planar coupling. A step-by-step design procedure is proposed, which aims at the maximization of the weak electromagnetic coupling between the RX and TX antennas integrated on side-by-side co-packaged [...] Read more.

This paper presents the design of on-chip micro-antennas for package-scale galvanic isolators based on RF planar coupling. A step-by-step design procedure is proposed, which aims at the maximization of the weak electromagnetic coupling between the RX and TX antennas integrated on side-by-side co-packaged chips to enable both high isolation rating and common-mode transient immunity thanks to the high dielectric strength and low capacitive parasitics of a molding compound-based galvanic barrier, respectively. Micro-antenna design guidelines are drawn, highlighting the main relationship between coil coupling performance and their layout parameters, which are often in contrast with respect to traditional integrated inductor ones. Full article

(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design, Volume II)

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15 pages, 1719 KiB

Open AccessArticle

Efficient Holographic Focusing Metasurface

by Vinay R. Gowda, Mohammadreza F. Imani, Timothy Sleasman and David R. Smith

Electronics 2021, 10(15), 1837; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151837 - 30 Jul 2021

Cited by 3 | Viewed by 2268

Abstract

We present the design and experimental demonstration of an efficient holographic metasurface aperture that focuses microwaves in the Fresnel zone. The proposed circular structure consists of two stacked plates with their periphery terminated in a conductive layer. Microwaves are injected into the bottom [...] Read more.

We present the design and experimental demonstration of an efficient holographic metasurface aperture that focuses microwaves in the Fresnel zone. The proposed circular structure consists of two stacked plates with their periphery terminated in a conductive layer. Microwaves are injected into the bottom plate, which forms the feed layer, and are coupled to the top holographic metasurface layer via an annular ring. This coupling results in an inward traveling cylindrical wave in the top layer, which serves as the reference wave for a hologram. The radiating elements consist of a slot pair with their orientations designed to couple efficiently with the cylindrical reference wave while maintaining a linearly polarized focused beam. A general condition on the slot pairs radiated power is proposed to ensure low sidelobe level (SLL) and is validated with full-wave simulation. An aperture that is 20 cm in diameter, operates at 20 GHz in the K-band frequency, and forms a diffraction-limited focal spot at a distance of 10 cm is experimentally demonstrated. The proposed near-field focusing metasurface has high antenna efficiency and can find application as a compact source for Fresnel-zone wireless power transfer and remote sensing schemes. Full article

(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design, Volume II)

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10 pages, 1656 KiB

Open AccessArticle

Compact and Simple High-Efficient Dual-Band RF-DC Rectifier for Wireless Electromagnetic Energy Harvesting

by Mohamed M. Mansour, Shota Torigoe, Shuya Yamamoto and Haruichi Kanaya

Electronics 2021, 10(15), 1764; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151764 - 23 Jul 2021

Cited by 7 | Viewed by 2836

Abstract

(1) Background: This work presents a high-efficiency, high sensitivity, compact rectifier based on a dual-band impedance matching network that employs a simple and straightforward T-matching circuit, for sub-1 GHz license-free applications. The development of a low-cost RF energy harvester dedicated to the ISM [...] Read more.

(1) Background: This work presents a high-efficiency, high sensitivity, compact rectifier based on a dual-band impedance matching network that employs a simple and straightforward T-matching circuit, for sub-1 GHz license-free applications. The development of a low-cost RF energy harvester dedicated to the ISM bands is introduced. The proposed rectifier design is optimized to operate at the sub-GHz frequency bands (0.9 to 2.4 GHz), specifically those at the ISM 900 and 2400 MHz. The motivation for this band is due to the low attenuation, well-known fundamental electromagnetic theories and background, and several wireless communications are emitting at those bands, such as RFID (2). Methods: The rectifier design is based on a simple, balanced single-series diode connected with a T-matching circuit. The dual-band performance is achieved by deploying reactive elements in each branch. The full mathematical analysis and simulation results are discussed in the manuscript. (3) Results: The rectifier can achieve a 80 MHz bandwidth around 920 MHz frequency and 200 MHz around the higher band 2.4 GHz. The resultant conversion efficiency level is maintained above 45% at both bands with a peak efficiency reaches up to 70% at the higher band. The optimum terminal load attached to the circuit at which the peak efficiency is achieved, is given as 4.7 k

Ω

. (4) Conclusion: Due to the compactness and small footprint, simple design, and simple integration with microwave circuits, the proposed rectifier architecture might find several potential applications in wireless RF energy harvesting. Full article

(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design, Volume II)

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21 pages, 8033 KiB

Open AccessArticle

A Simple WiFi Harvester with a Switching-Based Power Management Scheme to Collect Energy from Ordinary Routers

by Fernando Angulo, Loraine Navarro, Christian G. Quintero M. and Mauricio Pardo

Electronics 2021, 10(10), 1191; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10101191 - 17 May 2021

Cited by 3 | Viewed by 4820

Abstract

This paper shows the design process of a simplified harvesting circuit for WiFi at the 2.4 GHz frequency band based on the analysis of the environment available signals. Those signals and their power level define an antenna design to maximize captured energy and [...] Read more.

This paper shows the design process of a simplified harvesting circuit for WiFi at the 2.4 GHz frequency band based on the analysis of the environment available signals. Those signals and their power level define an antenna design to maximize captured energy and select the proper number of stages for a voltage multiplier so that an impedance matching network is no longer required. With this, it is possible to maintain the harvester architecture simple without sacrificing performance. The use of supercapacitors is preferred over batteries due to their high-power capacity, the ability to deliver high peak currents, long-life cycle size, and low cost. Hence, supercapacitor availability allows to devise a novel switching scheme that employs two units that favor energy use and speed up the recharging process. The built harvester exhibits a power conversion efficiency greater than 50% under an incident signal of 0 dBm in the rectenna. The tests are carried out in an academic environment using a multi SSID router, collecting 494 mJ without requiring special modifications in the router used as an energy source. Full article

(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design, Volume II)

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16 pages, 2970 KiB

Open AccessArticle

Constant Envelope Multiplexing of Multi-Carrier DSSS Signals Considering Sub-Carrier Frequency Constraint

by Xiaofei Chen, Xiaochun Lu, Xue Wang, Jing Ke and Xia Guo

Electronics 2021, 10(2), 211; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10020211 - 18 Jan 2021

Cited by 2 | Viewed by 1714

Abstract

With the development of global navigation satellite systems (GNSS), multiple signals modulated on different sub-carriers are needed to provide various services and to ensure compatibility with previous signals. As an effective method to provide diversified signals without introducing the nonlinear distortion of High [...] Read more.

With the development of global navigation satellite systems (GNSS), multiple signals modulated on different sub-carriers are needed to provide various services and to ensure compatibility with previous signals. As an effective method to provide diversified signals without introducing the nonlinear distortion of High Power Amplifier (HPA), the multi-carrier constant envelope multiplexing is widely used in satellite navigation systems. However, the previous method does not consider the influence of sub-carrier frequency constraint on the multiplexing signal, which may lead to signal power leakage. By determining the signal states probability according to the sub-carrier frequency constraint and solving the orthogonal bases according to the homogeneous equations, this article proposed multi-carrier constant envelope multiplexing methods based on probability and homogeneous equations. The analysis results show that the methods can multiplex multi-carrier signals without power leakage, thereby reducing the impact on signal ranging performance. Meanwhile, the methods could reduce the computation complexity. In the case of three different carriers multiplexing, the number of optimization equations is reduced by nearly 66%. Full article

(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design, Volume II)

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