scholarly journals Enhanced Broadband RF Differential Rectifier Integrated with Archimedean Spiral Antenna for Wireless Energy Harvesting Applications

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 655 ◽  
Author(s):  
Mohamed Mansour ◽  
Xavier Le Polozec ◽  
Haruichi Kanaya
Keyword(s):  
Conversion Efficiency ◽  
High Efficiency ◽  
Load Resistance ◽  
Dipole Antenna ◽  
Input Power ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Spiral Antenna ◽  
Archimedean Spiral ◽  
5 Ghz

This work addresses the design and implementation of a broadband differential rectifier (DR) combined with an Archimedean spiral dipole antenna (ASDA) for wireless power harvesting at low incident power densities below 200 μ W/cm 2 . The proposed design exhibits an improved RF-DC conversion efficiency over a wide frequency range from 1.2 to 5 GHz. This frequency band is associated with several wireless communication services, for instance, ISM, WLAN, 5G, LTE, and GPS applications. The receiving planar ASDA exhibits circular polarization and has an average measured gain of 4.5 dBi from 1.2 to 5 GHz. To enable a wide operating bandwidth, the rectifier circuit is constituted by two architectures, designated A and B. Each scheme is designed to harvest power efficiently across a specific bandwidth. The optimal performance of both rectifiers are obtained using the nonlinear harmonic-balance simulations. The antenna–rectifier integration yields a compact rectenna with a high-efficiency performance over the intended bandwidth from 1.2 to 5 GHz for an input power of 9 dBm and terminal load resistance of 1 k Ω . The total measured RF-DC conversion efficiency is maintained above 30% across the entire frequency range with a peak value of 61% achieved at 1.2 GHz. In comparison with similar architectures, the proposed rectenna maintains a stable output efficiency despite the wide fluctuations in the input frequency and also has a minimum footprint size (58 × 55 mm 2 ).

scholarly journals Broadband bifunctional Luneburg–Fisheye lens based on anisotropic metasurface

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiaqing Chen ◽  
Yongjiu Zhao ◽  
Lei Xing ◽  
Zheng He ◽  
Luyang Sun
Keyword(s):  
High Efficiency ◽  
Broad Band ◽  
Dipole Antenna ◽  
Wide Frequency Range ◽  
Experimental Results ◽  
Frequency Range ◽  
Fisheye Lens ◽  
Low Profile ◽  
Theoretical Predictions ◽  
Fisheye Lenses

AbstractLuneburg lenses and Maxwell fisheye lenses possess distinct properties of focusing, well beyond conventional lenses made of uniform materials. In this paper, a planar broadband bifunctional Luneburg-fisheye lens synthesized by gradient anisotropic metasurface is proposed. The proposed anisotropic metasurface is formed by non-resonant anisotropic cells, so that it can independently realize the equivalent gradient refractive indexes of Luneburg lens and Maxwell fisheye lens along orthogonal directions in a broad band, respectively. To verify the performance of the bifunctional lens, a prototype associated with a feeding log-periodic dipole antenna has been fabricated. Experimental results show that the proposed lens functions well over a wide frequency range with high efficiency and low profile, which coincides well with theoretical predictions and simulated results. It is expected that the proposed design will facilitate the applications of multifunctional metadevices in microwave and optical ranges.

scholarly journals Printed dipole antenna and its arrays for wireless applications

2018 ◽  
Vol 7 (2.7) ◽  
pp. 952
Author(s):  
V Teju ◽  
P V. P. S Nikhil ◽  
A Pranusha ◽  
Ch Divya ◽  
G Bhanuprakash
Keyword(s):  
Reflection Loss ◽  
Mutual Coupling ◽  
Dipole Antenna ◽  
Wide Frequency Range ◽  
Single Element ◽  
Frequency Range ◽  
Scanning Angle ◽  
Wireless Applications ◽  
Element Array

This paper proposes single element of micro-stripe antenna having wider bandwidth and also its arrays which are implemented for wire-less applications. In contemplation of wide frequency range of operation, antenna is fed with integrated balun. The single element antenna works under frequency range of 34GHz to 46GHz where reflection loss is less than -10dB and the obtained gain is 2.1 dBi. The linear 8-element array of antenna has been implemented and to obtain low mutual coupling between the elements of antenna a rectangular stub has been implemented. By enforcing the array methodology the not only the overall gain of the antenna has increased but also results in wider scanning angle.  

scholarly journals Efficient Numerical Full-Polarized Facet-Based Model for EM Scattering from Rough Sea Surface within a Wide Frequency Range

2019 ◽  
Vol 11 (1) ◽  
pp. 75 ◽  
Author(s):  
Jinxing Li ◽  
Min Zhang ◽  
Ye Zhao ◽  
Wangqiang Jiang
Keyword(s):  
Cross Sections ◽  
High Efficiency ◽  
Wide Frequency Range ◽  
Sea Surface ◽  
Doppler Spectrum ◽  
Frequency Range ◽  
Em Scattering ◽  
Wind Speeds ◽  
Novel Approach ◽  
Rough Sea Surface

A full-polarized facet based scattering model (FPFSM) for investigating the electromagnetic (EM) scattering by two-dimensional electrically large sea surfaces with high efficiency at high microwave bands is proposed. For this method, the scattering field over a large sea facet in a diffuse scattering region is numerically deduced according to the Bragg scattering mechanism. In regard to near specular directions, a novel approach is proposed to calculate the scattered field from a sea surface based on the second order small slope approximation (SSA-II), which saves computer memory considerably and is able to analyze the EM scattering by electrically large sea surfaces. The feasibility of this method in evaluating the radar returns from the sea surface is proved by comparing the normalized radar cross sections (NRCS) and the Doppler spectrum with the SSA-II. Then NRCS results in monostatic and bistatic configurations under different polarization states, scattering angles and wind speeds are analyzed as well as the Doppler spectrum at Ka-band. Numerical results show that the FPFSM is a reliable and efficient method to analyze the full-polarized scattering characteristics from electrically large sea surface within a wide frequency range.

Flexibly guiding of acoustic waves by one-dimensional sonic crystal with omnidirectional bandgap

2015 ◽  
Vol 29 (28) ◽  
pp. 1550193 ◽  
Author(s):  
Hai-Long He ◽  
Shi-Liang Ou-Yang ◽  
Zhaojian He ◽  
Ke Deng ◽  
Heping Zhao
Keyword(s):  
Numerical Simulations ◽  
Crystal Structures ◽  
Acoustic Waves ◽  
High Efficiency ◽  
Wide Frequency Range ◽  
Sound Waves ◽  
Frequency Range ◽  
Bending Angle ◽  
One Dimensional ◽  
Sonic Crystal

An acoustic waveguide based on the omnidirectional reflection of one-dimensional (1D) sonic crystal (sc) is designed to realize the flexible guiding of sound waves. Numerical simulations indicate that high-efficiency transmission can be achieved at arbitrary bending angle and over a wide frequency range. Moreover, flexible waveguide branches can also be easily constructed by introducing more crystal structures into the waveguides. Owing to its designing flexibility, this waveguide would be very useful in various integrated applications based on SCs.

Non-invasive detection and discrimination of breast tumors at early stage using spiral antenna

Frequenz ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Rukmani Singh ◽  
Vishnu Priye
Keyword(s):  
Early Stage ◽  
Low Cost ◽  
Breast Tumors ◽  
Tumor Location ◽  
Petroleum Jelly ◽  
Frequency Range ◽  
Spiral Antenna ◽  
Archimedean Spiral ◽  
Non Invasive ◽  
Full Wave

AbstractIn this paper, an Archimedean spiral antenna-based biosensor has been proposed for the early detection of breast tumor. By monitoring the variation of S11 over 1–3.5 GHz frequency range, the proposed scheme can identify the tumor location, as well as distinguish the types of tumor (benign or malignant) based on shapes and dielectric properties contrast. To validate the concept, full wave simulation using CST microwave suite are performed along with VNA based experimental measurements on breast phantoms and tumors, prepared by easily available materials like glass, petroleum jelly, mixture of water and wheat flour. The demonstrated device is able to detect the tumor of less than 1 mm in radius and positioned anywhere in 5 × 5 × 5 cm of breast fat. The proposed method is easy to use, low cost, safe, comfortable, non-invasive and non- ionizing in nature.

scholarly journals Ultra-Wideband Low-Cost High-Efficiency Cavity-Backed Compound Spiral Antenna

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1399
Author(s):  
Charl Baard ◽  
Yulang Liu ◽  
Natalia Nikolova
Keyword(s):  
Time Domain ◽  
High Efficiency ◽  
Low Cost ◽  
Ultra Wideband ◽  
Impedance Bandwidth ◽  
Competitive Performance ◽  
Spiral Antenna ◽  
Archimedean Spiral ◽  
Backward Radiation ◽  
Equiangular Spiral

A low-cost high-efficiency ultra-wideband (UWB) cavity-backed spiral antenna is proposed. It employs an equiangular spiral enclosed by an Archimedean spiral and it is fed through a tapered microstrip balun. A center-raised cylindrical absorber-free cavity backs the spiral to minimize the backward radiation without decreasing the efficiency. The cavity is designed to ensure an impedance bandwidth exceeding 16:1 ratio (from 350 MHz to 5.5 GHz). Simulated and measured results are presented and compared, demonstrating competitive performance in terms of impedance bandwidth and efficiency. Time–domain measurements indicate fidelity of 0.62 at boresight.

scholarly journals A High-Efficiency Self-Synchronous RF–DC Rectifier Based on Time-Reversal Duality for Wireless Power Transfer Applications

Electronics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 90
Author(s):  
Ying Wang ◽  
Gao Wei ◽  
Shiwei Dong ◽  
Yazhou Dong ◽  
Xumin Yu ◽  
...  
Keyword(s):  
Time Reversal ◽  
High Efficiency ◽  
Design Method ◽  
Wireless Power Transfer ◽  
Operating Mode ◽  
Load Resistance ◽  
Input Power ◽  
Adjustment Process ◽  
Power Transfer ◽  
Wireless Power

An RF–DC rectifier is an important part in a wireless power transfer system. Diode-based rectifiers are widely used in low-power harvesting scenarios, and for high power, a transistor based on the time-reversal duality was proposed. This paper presents a high-efficiency self-synchronous RF–DC rectifier based on a waveform-guided design method and an improved rectification model of a commercial GaN device. The main contributions of this paper are that (1) an improved transistor model with correct reverse bias is built for accurate rectifier simulation, and (2) a new design method of self-synchronous RF–DC rectifier is proposed: as soon as the operating mode of the rectifier, input power, and DC load are set, matching and coupling network can be calculated directly based on waveform-guided method, thus design and adjustment process of a conventional power amplifier (PA) due to the duality between a PA and a rectifier would no longer be required. A 5.8 GHz self-synchronous RF–DC rectifier is designed for validation, and the optimum RF–DC conversion efficiency is 68% with 12 W input power as well as 19.9 V output DC potential with 50 Ω load resistance. The proposed rectifier is suitable for high input power rectification applications of wireless power transfer.

scholarly journals Effect of Parallel Capacitor in Matching Network of RF Energy Harvesting Circuit

2019 ◽  
Vol 7 (4) ◽  
pp. 19-24
Author(s):  
Pankaj Agrawal ◽  
Bharat Mishra ◽  
Akhilesh Tiwari
Keyword(s):  
Energy Harvesting ◽  
Conversion Efficiency ◽  
Output Voltage ◽  
Optimization Technique ◽  
Load Resistance ◽  
Input Power ◽  
Variable Load ◽  
Matching Network ◽  
Rf Energy Harvesting ◽  
Rf Energy

This paper is an outcome of a wide research on RF energy harvesting techniques presented so far along with the development and implementation of the new idea of using a matching network with and without including parallel capacitance. While working with variable signal power in RF energy harvesting there is always a problem with nonlinear behavior of rectifying diode in harvesting circuit, to overcome the same a variety of matching networks are proposed in this manuscript with the variable RF power along with the variable load. Simulation results shows that output has been achieved upto 1.8Volts with maximum power conversion efficiency up to 79% at -10 dBm input power. Experimental results represented DC output of 1.62 volts at a frequency of 900 MHz with -10 dBm input power. Optimization technique is used to select parameters value which maximizes output voltage and efficiency. Variation of load resistance and input power plays a major role in output voltage and conversion efficiency. Comparison of the same is also presented in this particular research paper.

scholarly journals Quad-Band 3D Rectenna Array for Ambient RF Energy Harvesting

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Fatima Khalid ◽  
Warda Saeed ◽  
Nosherwan Shoaib ◽  
Muhammad U. Khan ◽  
Hammad M. Cheema
Keyword(s):  
Energy Harvesting ◽  
Conversion Efficiency ◽  
Mobile Communications ◽  
Hybrid Approach ◽  
Ring Structure ◽  
Dipole Antenna ◽  
Input Power ◽  
Wire Antenna ◽  
Iot Devices ◽  
Indoor And Outdoor

This paper presents a quad-band, 3D mountable rectenna module for ambient energy harvesting. With the aim of powering up Internet of Things (IoT) nodes in practical ambient environments, a hybrid approach of combining power, both at RF and DC, is adopted using 98 MHz FM band, GSM900 (Global System for Mobile Communications), GSM1800, and Wi-Fi 2.4 GHz band. A dual polarized cross-dipole antenna featuring asymmetric slots as well as central ring structure enables multiband response and improved matching at the higher three frequency bands, whereas a loaded monopole wire antenna is used at the lower FM band. Four identical multiband antennas are placed in a 3D cubic arrangement that houses a 4-to-1 power combiner and matching circuits on the inside and the FM antenna on the top. In order to maintain stable rectenna output at varying input power levels and load resistances, a novel transmission line based matching network using closed form equations is proposed. Integrated in form of a 10 × 10 × 10 cm3 cube using standard FR4 substrate, the rectenna generates a peak output voltage of 2.38 V at −10 dBm input power. The RF to DC conversion efficiency is 70.28%, 41.7%, 33.37%, and 27.69% at 98 MHz, 0.9 GHz, 1.8 GHz, and 2.4 GHz, respectively, at −6 dBm. The rectenna also exhibits a measured conversion efficiency of 31.3% at −15 dBm for multitone inputs in ambient environment. The promising results in both indoor and outdoor settings are suitable to power low power IoT devices.

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