scholarly journals Simulation of impedance measurements at human forearm within 1 kHz to 2 MHz

2019 ◽  
Vol 7 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Gautam Anand ◽  
Andrew Lowe ◽  
Ahmed M. Al-Jumaily
Keyword(s):  
High Frequency ◽  
Simulation Analysis ◽  
Electrical Response ◽  
Dielectric Behavior ◽  
Cole Plot ◽  
Frequency Range ◽  
Impedance Measurements ◽  
High Frequency Structure Simulator ◽  
Human Forearm ◽  
Different Diameters

Abstract This work presents a simulation analysis of the bioimpedance measurements at the human forearm. The Ansys® High Frequency Structure Simulator (HFSS) has been used to analyze the electrical response of a section of human forearm with three domains of dielectric behavior – fat, muscle and artery (blood). The impedance values were calculated as the ratio of the output voltage at the electrodes to the applied known current (1 mA). A model was developed and was simulated for impedance values obtained within a frequency range of 1 kHz to 2 MHz. The measurements were done at three instances of radial artery diameter. The maximum resistance and reactance values were calculated as 445 Ω and 178.5 Ω, 356 Ω and 138 Ω, and 368 Ω and 144.3 Ω for diameters 2.3 mm, 2.35 mm, and 2.4 mm respectively. The set of impedance values obtained followed the Cole-plot trend. The results obtained were found to be in excellent agreement with the Cole modelling. The set of values obtained at three different diameters reflected the effect of blood flow on impedance values.

Investigation of dielectric behavior of thermally aged XLPE cable in the high-frequency range

2006 ◽  
Vol 25 (4) ◽  
pp. 553-561 ◽  
Author(s):  
Chonung Kim ◽  
Zhijian Jin ◽  
Pingkai Jiang ◽  
Zishu Zhu ◽  
Genlin Wang
Keyword(s):  
High Frequency ◽  
Dielectric Behavior ◽  
High Frequency Range ◽  
Frequency Range ◽  
Xlpe Cable

Compact 5G Hairpin Bandpass Filter Using Non-Uniform Transmission Lines Theory

2021 ◽  
Vol 36 (2) ◽  
pp. 126-131
Author(s):  
Sahar Saleh ◽  
Widad Ismail ◽  
Intan Zainal Abidin ◽  
Moh’d Jamaluddin
Keyword(s):  
Frequency Band ◽  
Transmission Lines ◽  
High Frequency ◽  
Bandpass Filter ◽  
Impedance Matching ◽  
Low Frequency ◽  
Frequency Range ◽  
High Frequency Structure Simulator ◽  
Wireless Transmitter ◽  
Reduction Percentage

A compact three order 5G low frequency band Hairpin Bandpass Filter (HPBF) is analyzed, designed and fabricated in this paper. The designed filter operates at 5G frequency range (5.975-7.125 GHz). 17.76% compactness in each λ/2 uniform transmission line (UTL) resonator of the filter is achieved by applying Non-Uniform Transmission Lines (NTLs) theory. This compactness will make modern wireless transmitter and receiver designs more compatible. Study on the best reduction size percentage and suitable constraints to design the required NTL resonator is highlighted in this paper. Six samples with different size reductions percentage are fabricated and measured. The simulation is carried out in this study uses High Frequency Structure Simulator (HFSS) software and Computer Simulation Technology (CST) software. The simulated results for UTL HPBF and NTL HPBF with the six cases are verified with measurement. For the best size reduction percentage design, the measured results demonstrated that the 6.55 GHz NTL and UTL HPBF show good impedance matching within the unsilenced 5G frequency band.

scholarly journals Simulation of Impedance Measurements at Human Upper Arm within 10 KHZ to 1 MHZ with the Vary of Fat Layers from 10MM to 25MM

10.29007/rz1b ◽  
2020 ◽  
Author(s):  
Minh Hiep Do Tran ◽  
Phuong Vi Ngo ◽  
Quang Linh Huynh ◽  
Thuy Nguyen Nhu Son
Keyword(s):  
Output Voltage ◽  
3D Model ◽  
Simulation Analysis ◽  
Dielectric Behavior ◽  
Comsol Multiphysics ◽  
The Finite Element Method ◽  
Applied Current ◽  
Upper Arm ◽  
Impedance Measurements ◽  
Fat Thickness

The work presents a simulation analysis of the bioimpedance at the human upper arm using the finite element method (FEM). Comsol Multiphysics has been used to create the 3D model with four domains of dielectric behavior: skin, fat, muscle, and bone. The main objective of this paper is to study the effect of the fat thickness and frequency on three parameters: resistance, reactance, and phase. The impedance values were calculated as the ratio of the output voltage at the electrodes and the applied current (1 mA). The measurements were done at four different values of the fat layer (10mm, 15mm, 20mm, and 25mm) and the electrical properties of the upper arm were used. The results clarify that the fat layer has a significant impact on the upper arm impedance across the frequency spectrum, resistance, and phase appear to be more affected than reactance.

scholarly journals On the Design of 2×2 MIMO Fractal Antenna Array for C band applications

2019 ◽  
Vol 8 (10) ◽  
pp. 2231-2235
Keyword(s):  
Antenna Array ◽  
High Frequency ◽  
Unit Element ◽  
Fractal Antenna ◽  
Frequency Range ◽  
Band Frequency ◽  
High Frequency Structure Simulator ◽  
Feed Line ◽  
Microstrip Feed Line ◽  
Microstrip Feed

A 2×2 MIMO planar fractal antenna array using Sierpinski gasket along with microstrip feed line has been investigated. Different configurations of antenna array has been studied. The optimized unit element used in array is further modified geometrically by corner rounding and cut in feed to improve its performance including gain. Proposed fractal array antenna resonates at 4.19 GHz and 7.86 GHz lies in C band and simulated using High frequency structure simulator. Such an attempt has been rarely reported in the literature. Simulated reflection coefficient shows that Proposed antenna works in C band frequency range for various applications and results are quite promising

scholarly journals Designing a Microstrip Patch Antenna in Part of Ultra-Wideband Applications

2020 ◽  
Vol 17 (4) ◽  
pp. 1216
Author(s):  
Wa'il A. Godaymi Al-Tumah ◽  
Raed Shaaban ◽  
Zeki Ahmed
Keyword(s):  
High Frequency ◽  
Microstrip Antenna ◽  
Return Loss ◽  
Microstrip Patch Antenna ◽  
Ultra Wideband ◽  
Frequency Range ◽  
High Frequency Structure Simulator ◽  
Microstrip Patch ◽  
Rectangular Patch ◽  
Rectangular Microstrip Antenna

In this work, a simulated study was carried out for designing a novel spiral rectangular patch of microstrip antenna that is used in ultra-wideband applications by using a high frequency structure simulator software (HFSS). A substrate with dielectric constant of 4.4 and height 2.10 mm (commercial substrate height available is about 0.8-1.575 mm) has been used for the design of the proposed antenna. The design basis for enhancing bandwidth in the frequency range 6.63 - 10.93 GHz is based on increasing the edge areas that positively affect the antenna's efficiency. This design makes the designed antenna cost less by reducing the area of the patch. It has been noticed that the bandwidth of the antenna under this study is increasing to 4.30 GHz or 61% compared with 3.6% for the standard rectangular microstrip antenna with the same dimensions of the proposed antenna. The antenna also maintains the voltage standing wave ratio of 1.09 at resonant frequency 7.07 GHz, return loss -27.07 dB, and the amount of impedance in real and imaginary parts 51.5Ω and 3.3Ω, respectively.

scholarly journals A Metamaterial Inspired UWB Circular Antenna as Superstrate for Gain and Directivity Improvement’s

2019 ◽  
Vol 8 (12) ◽  
pp. 496-499
Keyword(s):  
High Frequency ◽  
Impedance Matching ◽  
Wave Impedance ◽  
Frequency Range ◽  
High Frequency Structure Simulator ◽  
Bending Waves ◽  
Metamaterial Antenna ◽  
Effective Wave ◽  
Approach Zero ◽  
Zero Index

A Near Zero refractive Index (NZIM) metamaterial inspired UWB circular antenna as a superstrate for gain and directivity improvement’s is presented and investigated in this work. The frequency range with S11 less than -10dB is from 4.5GHz to 12.5GHz. The permeability and permittivity of the (NZIM) has an extraordinary property that could be optimized to synchronously approach zero and have an effective wave impedance matching with air and near-zero index simultaneously, this feature of metamaterial gives the NZIM the ability to collimates the incident bending waves and gather it’s towards the normal direction. Hence the antenna performances in term of the gain and directivity will be enhanced. The studied metamaterial design is optimized and analyzed using CST microwave. Obviously, the antenna gain and directivity are enhanced by 4.8 and 4.89 respectively. The simulation of this developed metamaterial antenna has been optimized and performed by using Computer Simulation TechnologyMicrowave Studio (CST) and Ansof High Frequency Structure Simulator (HFSS)

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

HIGH FREQUENCY OHMIC LOSSES IN TERAHERTZ FREQUENCY RANGE CW KLYNOTRONS

2017 ◽  
Vol 76 (10) ◽  
pp. 929-940 ◽  
Author(s):  
Yu. S. Kovshov ◽  
S. S. Ponomarenko ◽  
S. A. Kishko ◽  
A. A. Likhachev ◽  
S. A. Vlasenko ◽  
...  
Keyword(s):  
High Frequency ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Ohmic Losses

scholarly journals Couplinator: A simple computational tool for synthesis of multi-section coupled-line filter based on MPCM-TLM technique

2021 ◽  
pp. 1-10
Author(s):  
E. Faghand ◽  
S. Karimian ◽  
E. Mehrshahi ◽  
N. Karimian
Keyword(s):  
Comparative Analysis ◽  
Transmission Line ◽  
High Frequency ◽  
Computational Tool ◽  
Cad Tools ◽  
Coupled Line ◽  
High Frequency Structure Simulator ◽  
Transmission Line Method ◽  
Set Up ◽  
Planar Circuit

Abstract A new simple computational tool is proposed for the synthesis of multi-section coupled-line filters based on combined modified planar circuit method (MPCM) and transmission line method (TLM) analysis, referred to as MPCM-TLM. Due to its fundamentally simple architecture, the presented tool offers significantly faster optimization of coupled-line filters – for exactly the same initial simulation set-up – than other costly commercially-available tools, giving equally reliable results. Validity and accuracy of the proposed tool have been verified through the design of 3rd, 5th, and 7th order coupled-line filters and comparative analysis between results obtained from the proposed approach and the high-frequency structure simulator. A remarkable 99% time reduction in the analysis is recorded in the case of 7th order filter using the proposed tool, for almost identical results to HFSS. Therefore, it can be confidently claimed that the proposed technique can be used as a reliable alternative to existing complex, costly, processor-intensive CAD tools.

scholarly journals An Improved Time Integration Method Based on Galerkin Weak Form with Controllable Numerical Dissipation

2021 ◽  
Vol 11 (4) ◽  
pp. 1932
Author(s):  
Weixuan Wang ◽  
Qinyan Xing ◽  
Qinghao Yang
Keyword(s):  
High Frequency ◽  
Integration Method ◽  
Time Integration ◽  
Low Frequency ◽  
Weak Form ◽  
High Accuracy ◽  
Numerical Dissipation ◽  
Frequency Range ◽  
Time Integration Method ◽  
Numerical Damping

Based on the newly proposed generalized Galerkin weak form (GGW) method, a two-step time integration method with controllable numerical dissipation is presented. In the first sub-step, the GGW method is used, and in the second sub-step, a new parameter is introduced by using the idea of a trapezoidal integral. According to the numerical analysis, it can be concluded that this method is unconditionally stable and its numerical damping is controllable with the change in introduced parameters. Compared with the GGW method, this two-step scheme avoids the fast numerical dissipation in a low-frequency range. To highlight the performance of the proposed method, some numerical problems are presented and illustrated which show that this method possesses superior accuracy, stability and efficiency compared with conventional trapezoidal rule, the Wilson method, and the Bathe method. High accuracy in a low-frequency range and controllable numerical dissipation in a high-frequency range are both the merits of the method.

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