scholarly journals Gel-Like Human Mimicking Phantoms: Realization Procedure, Dielectric Characterization and Experimental Validations on Microwave Wearable Body Sensors

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 111
Author(s):  
Sandra Costanzo ◽  
Vincenzo Cioffi ◽  
Adil Masoud Qureshi ◽  
Antonio Borgia
Keyword(s):  
Low Cost ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Perfect Agreement ◽  
Dielectric Characterization ◽  
Human Arm ◽  
Body Sensors ◽  
Experimental Validations ◽  
5 Ghz

A simple and low-cost procedure for gel-like time-durable biological phantoms is presented in this work. Easily accessible materials are adopted, which are able to provide a flexible and controllable method to rapidly realize different kind of tissues. The proposed technique is applied to fabricate various tissue-mimicking phantoms, namely skin, muscle, blood and fat. Their effectiveness is first tested by performing dielectric characterization on a wide frequency range, from 500 MHz up to 5 GHz, and validating the measured dielectric parameters (dielectric constant and conductivity) by comparison with reference models in the literature. Then, a multi-layer phantom simulating the human arm is realized, and a wearable body sensor is adopted to prove the perfect agreement of the biometric response achieved in the presence of the fabricated phantom and that provided by a real human arm.

scholarly journals LOW-COST, INTELLIGENT DATA ACQUISITION SYSTEM FOR QCM AND OTHER RESONATOR-BASED BIO- AND CHEMICAL SENSORS

2014 ◽  
pp. 9-17
Author(s):  
Sergey Y. Yurish
Keyword(s):  
Data Acquisition ◽  
Integrated Circuit ◽  
Low Cost ◽  
Data Acquisition System ◽  
Wide Frequency Range ◽  
Acquisition System ◽  
Bulk Acoustic Wave ◽  
Frequency Range ◽  
Modified Method ◽  
Intelligent Data Acquisition

A low-cost, intelligent data acquisition system for quartz crystal microbalance (QCM) and other (superficial SAW and bulk acoustic wave) resonator-based chemical and biosensors described in this article. The system is based on the novel modified method of the dependent count and allows obtaining high metrological performances: programmable and constant in all frequency range relative error of measurement up to 0,0005 % (5 ppm); nonredundant, reduced conversion time of measurement and wide frequency range from 0.05 Hz to 9 MHz (144 MHz with prescaling). The developed system allows measuring variations of the resonance frequency shift for QCM sensors working in liquids and gases. The described low-cost data acquisition system is based on novel integrated circuit of universal frequency-to-digital converter. This design approach has eliminated much of the hardware: there is no need for a microcontroller and complex sensor interfacing electronics, as it is directly compatible with PC computers.

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 Simulation of electromagnetic field distribution in the measuring cell for determining the dielectric permittivity of materials at microwave frequencies

Doklady BGUIR ◽  
2020 ◽  
Vol 18 (6) ◽  
pp. 75-80
Author(s):  
N. A. Pevneva ◽  
A. A. Kopshai ◽  
A. L. Gurskii
Keyword(s):  
Electromagnetic Field ◽  
Dielectric Permittivity ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Polyethylene Tube ◽  
Dielectric Parameters ◽  
Measuring Cell ◽  
Ansoft Hfss

To determine the dielectric permittivity of materials in a wide frequency range with the automation of measurements and the necessary accuracy, measuring cells have been created to ensure the simplicity of the design of the waveguide path. In order to obtain information about the suitability of measuring cells based on irregular SHF waveguides for estimation of dielectric parameters of materials, we simulated the structure of electromagnetic field in the system consisting of two irregular waveguides and waveguide chamber placed between them using a three-dimensional electrodynamic simulation in Ansoft HFSS package environment. The distribution of the electric field was simulated when an empty polyethylene tube, a rod of fluoroplastic and a rod of textolite are placed in the measuring cell. It was demonstrated that high order modes fade out in irregular waveguide and do not affect the precision of obtained results, and significant edge effects were not detected. It allows one to utilize measuring cells based on irregular waveguides together with a scalar or vector network analyzer and using the partial filling of the waveguide method or the modified Nicholson – Ross – Weir method for measurements of dielectric permittivity  of materials. The results of modeling the dependence of the amplitude and phase of the reflection coefficient of the textolite and fluoroplastic on the frequency in Ansoft HFSS environment are given. The simulation results are compared with the results obtained experimentally. The frequency dependencies of  were obtained experimentally for test materials – textolite and fluoroplastic – in the frequency range of 25,95–37,50 GHz. The experimental data are in satisfactory agreement with the results of theoretical calculations and do not go beyond the boundaries specified by the measurement uncertainty.

Tunable multiport system for measurement of two-port scattering parameters

2015 ◽  
Vol 9 (1) ◽  
pp. 99-112 ◽  
Author(s):  
Kamil Staszek ◽  
Slawomir Gruszczynski ◽  
Krzysztof Wincza
Keyword(s):  
Power Distribution ◽  
Wide Frequency Range ◽  
Measuring System ◽  
Scattering Parameters ◽  
Frequency Range ◽  
Measurement Results ◽  
Coefficient Measurement ◽  
5 Ghz ◽  
System Configurations ◽  
Maximum Measurement

A novel multiport system, allowing for measurements of scattering parameters in over-two-octave frequency range is proposed. It is composed of two directional couplers and a standard 4 × 4 Butler matrix, and does not require any isolators. The presented system features a uniform power distribution providing the high precision of measurements, which can be further enhanced by a simple adjustment of the system's parameters. A comprehensive analysis of the proposed system configurations, a fully analytical calibration for transmission coefficient measurement, and the estimation of maximum measurement error are given. The proposed measuring system has been experimentally verified in a wide frequency range 1–5 GHz, by measurements of S-parameters of exemplary components. The measurement results are very close to the values obtained with the use of a commercial vector network analyser within the 50 dB range of measured values’ magnitude.

scholarly journals Materials with high dielectric permeability on the basis of spontaneously polarized systems, lithium conductors and transition metal oxides

2021 ◽  
pp. 67-78
Author(s):  
Anatolii G. Belous ◽  
◽  
Oleg I. V'yunov ◽  
Oleg Z. Yanchevskii ◽  
Leonid L. Kovalenko ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Wide Frequency Range ◽  
Dielectric Losses ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Low Frequencies ◽  
Low Dielectric ◽  
Constant E ◽  
High Dielectric

Materials with a high dielectric constant (e > 1000) based on complex oxides of spontaneously polarized systems, lithium-conducting systems, and oxides of transition metals were studied. It was shown in dielectric ceramics Ba(Ti,Sn)O3 the absence of significant dispersion of dielectric parameters (e and tg δ) in a wide frequency range from 1 to 105 Hz. The introduction of MnO2 and Al2O3-SiO2-TiO2 improves dielectric parameters and reduces sintering temperature. Obtained ceramic materials are characterized by high dielectric constant values e ~ 13000–16000 and low dielectric losses tg d ~ 0.05–0.06 (at 1 MHz). Synthesized solid solutions of La0.5Li0.5-xNaxTiO3 system, where x = 0 and 0.1, have high values e¢ > 104 at low frequencies (f ≤ 10 Hz). Dielectric properties of these materials are determined by the lithium ions mobility that increases with the rise of sodium content by increasing bottleneck size and decreases by the number of lithium vacancies reduction. The disadvantage of such materials is the decrease in dielectric constant with frequency increase. It was found that the ceramic СaСu3Тi4–xAlxО12-y-0.5xFy with x/y = 0.04/0.04 after sintering for 10 h is characterized by dielectric parameters: e¢ » 71000 (1 kHz) and tg d » 0.047. Introduction of aluminum (x/y = 0.04/0) or fluorine (0/0.08) in CCTO reduces dielectric losses (tg d » 0.044). The advantages of this type of material are a wide frequency range of high dielectric constant and relatively low dielectric loss. Synthesized materials can be used for the development of ceramic capacitors with high characteristics.

Characterization of Multilayer Ferroelectric Ceramic Capacitors in a Wide Frequency Range for RF Applications

2014 ◽  
Vol 975 ◽  
pp. 61-66
Author(s):  
Lauro Paulo Silva Neto ◽  
Jose O. Rossi ◽  
Joaquim J. Barroso
Keyword(s):  
Printed Circuit Boards ◽  
Ferroelectric Ceramic ◽  
Wide Frequency Range ◽  
Electronic Circuits ◽  
Frequency Range ◽  
Multilayer Ceramic Capacitors ◽  
Dielectric Characterization ◽  
Ceramic Capacitors ◽  
Multilayer Ceramic

Surface mount devices (SMDs) such as multilayer ceramic capacitors (MLCCs) have been widely used to reduce the size of electronic circuits as they are mounted directly onto the surface of printed circuit boards (PCBs) and are smaller than their through-hole counterparts because SMDs have shorter internal leads or no leads at all. Another advantage of these components is the lower parasitic inductance, which results in a higher resonant frequency. This work reports on the dielectric characterization of four commercial multilayer ceramic capacitors in a broad frequency range from 0.01 GHz to 2 GHz. The dielectric characterization consists of measuring the reflection coefficient S11 (real and imaginary parts) as function of frequency to calculate the permittivity, impedance and loss tangent of the capacitors tested. In addition, dielectric chemical composition is determined using surface X-ray spectroscopy (EDS). The results show that MLCCs have a resonance frequency higher than 0.3 GHz depending on the value of their capacitance, making them suitable for use in RF equipment, mobile phones, radars, and microwave electronic circuits.

Low-cost laser-cut patterned chips for acoustic concentration of micro to nano particles and cells by operating over a wide frequency range

The Analyst ◽  
2021 ◽  
Author(s):  
Jingui Qian ◽  
Wei Huang ◽  
Renhua Yang ◽  
Raymond H. W. Lam ◽  
Joshua Lee
Keyword(s):  
Acoustic Field ◽  
Particle Concentration ◽  
Low Cost ◽  
Wide Frequency Range ◽  
Nano Particles ◽  
Cell Manipulation ◽  
Label Free ◽  
Frequency Range ◽  
Spatial Asymmetry

Acoustofluidic platforms for cell manipulation benefit from being contactless and label-free at potentially low cost. Particle concentration in a droplet relies on augmenting spatial asymmetry in the acoustic field, which...

Microwave wide band absorption by carbon from Corn cob-1

2016 ◽  
Vol 12 (2) ◽  
pp. 4204-4212 ◽  
Author(s):  
Maheshwar Sharon ◽  
Ritesh Vishwakarma ◽  
Abhijeet Rajendra Phatak ◽  
Golap Kalita ◽  
Nallin Sharma ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Agricultural Waste ◽  
Wide Band ◽  
Nickel Nitrate ◽  
Equivalent Amount ◽  
Frequency Range ◽  
Corn Cob ◽  
Different Temperatures ◽  
Band Absorption ◽  
5 Ghz

Corn cob, an agricultural waste, is paralyzed at different temperatures (700oC, 800oC and 900oC). Microwave absorption of carbon in the frequency range of 2 GHz to 8 GHz is reported. Carbon activated  with 5%  nickel nitrate showed more than 90% absorption of microwave in the frequency range from 6 GHz to 8 GHz, while carbon activated  with 10% Nickel nitrate treated corn cob showed 90% absorption  in the frequency range of 2.5 GHz to 5 GHz. Carbon showing the best absorption are characterized by XRD, Raman spectra and SEM . It is suggested that corn cob treatment   alone with KOH did not improve the microwave absorption, whereas treatment along with nickel nitrate improved the absorption property much better. It is proposed that treatment with nickel nitrate helps in creating suitable pores in carbon   which improved the absorption behavior because while treating carbon with 1N HCl helps to leach out nickel creating equivalent amount of pores in the carbon.

Sign in / Sign up

Export Citation Format

Share Document