scholarly journals Impact of Dielectric Constant on Embedded Antenna Efficiency

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Van Thuan Nguyen ◽  
Chang Won Jung
Keyword(s):  
Dielectric Constant ◽  
Human Body ◽  
Human Muscle ◽  
Radiation Efficiency ◽  
Liquid Environment ◽  
Antenna Efficiency ◽  
Embedded Antennas ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

The impact of dielectric constant on radiation efficiency of embedded antenna located inside human body or another liquid environment is investigated both analytically and numerically. Our research is analysed and simulated at 403 MHz in the MedRadio band (401–406 MHz) and within a block of 2/3 human muscle phantom. Good agreement is achieved between analysis and simulation results. This work provides a guidance in selecting insulator for embedded antennas.

scholarly journals Measuring Hydrometeors Using a Precipitation Microphysical Characteristics Sensor: Sampling Effect of Different Bin Sizes on Drop Size Distribution Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xichuan Liu ◽  
Taichang Gao ◽  
Yuntao Hu ◽  
Xiaojian Shu
Keyword(s):  
Drop Size ◽  
Rain Rate ◽  
Monte Carlo Model ◽  
Rain Gauge ◽  
Sampling Schemes ◽  
Distribution Parameters ◽  
Optimum Sampling ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

In order to improve the measurement of precipitation microphysical characteristics sensor (PMCS), the sampling process of raindrops by PMCS based on a particle-by-particle Monte-Carlo model was simulated to discuss the effect of different bin sizes on DSD measurement, and the optimum sampling bin sizes for PMCS were proposed based on the simulation results. The simulation results of five sampling schemes of bin sizes in four rain-rate categories show that the raw capture DSD has a significant fluctuation variation influenced by the capture probability, whereas the appropriate sampling bin size and width can reduce the impact of variation of raindrop number on DSD shape. A field measurement of a PMCS, an OTT PARSIVEL disdrometer, and a tipping bucket rain Gauge shows that the rain-rate and rainfall accumulations have good consistencies between PMCS, OTT, and Gauge; the DSD obtained by PMCS and OTT has a good agreement; the probability of N0, μ, and Λ shows that there is a good agreement between the Gamma parameters of PMCS and OTT; the fitted μ-Λ and Z-R relationship measured by PMCS is close to that measured by OTT, which validates the performance of PMCS on rain-rate, rainfall accumulation, and DSD related parameters.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

scholarly journals Impact Energy and Angular Dependence of L X-ray Emission from a Thick Polycrystalline Tungsten Element Induced by 15–25 keV Electrons

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 82
Author(s):  
Bhupendra Singh ◽  
Suman Prajapati ◽  
Bhartendu K. Singh ◽  
R. Shanker
Keyword(s):  
Angular Dependence ◽  
Impact Energy ◽  
Intensity Ratio ◽  
Incidence Angle ◽  
Angular Variation ◽  
Measured Intensity ◽  
Polycrystalline Tungsten ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

The impact energy and angular dependence of L X-rays of a thick polycrystalline tungsten (W; atomic number, Z = 74) target induced by 15–25 keV electrons has been measured at different angles varying from 15° to 75° at intervals of 5° using a Si PIN photodiode detector. The variation of measured relative intensity of Ll, Lα, Lβ and Lγ characteristic lines as a function of incidence angle is found to be anisotropic and the measured variation compares well with the PENELOPE simulation results. The angular variation of intensity ratio of Ll/Lα and Lβ/Lα shows anisotropic distribution, whereas the angular variation of the Lγ/Lα ratio exhibits almost isotropic distribution within the uncertainty of measurements. These measured ratios are found to be in good agreement with Monte Carlo (MC) calculations. The measured intensity ratios of Lβ/Lα and Lγ/Lα at a given incidence angle show a linear dependence with impact energy and exhibit good agreement with simulation results; however, the measured intensity ratio of Ll/Lα shows a non-linear variation with the impact energy and yields poor agreement with theoretical calculations.

scholarly journals Design and Investigation of Disk Patch Antenna with Quad C-Slots for Multiband Operations

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
J. A. Ansari ◽  
Sapna Verma ◽  
Ashish Singh
Keyword(s):  
Dielectric Constant ◽  
Radiation Pattern ◽  
Patch Antenna ◽  
The Other ◽  
Substrate Thickness ◽  
Antenna Efficiency ◽  
X Band ◽  
Resonance Frequencies ◽  
Optimum Geometry ◽  
Good Agreement

An investigation into the design and fabrication of multiband disk patch antenna with symmetrically quad C-slots is presented in this paper. The proposed antenna shows multiband resonance frequencies which highly depend on substrate thickness, dielectric constant, and radius of the disk patch. By incorporating two pairs of C-slots in optimum geometry on the radiating patch, the proposed antenna operates between 2 and 12 GHz at different frequency bands centered at 2.27, 7.505, 9.34, 10.33, and 11.61 GHz. The other antenna parameters are studied like gain, antenna efficiency, and radiation pattern. The proposed antenna may find applications in S-, C-, and X-band. The results are carried out with the aid of HFSS and MOM-based IE3D simulator. The measured and simulated results are in good agreement with each other.

scholarly journals The Improved Radiations in Planar Microstrip Patch Antenna using Linear Slot Etched Ground Plane

2020 ◽  
Vol 8 (6) ◽  
pp. 123-127
Keyword(s):  
Dielectric Constant ◽  
Resonant Frequency ◽  
Patch Antenna ◽  
Ground Plane ◽  
Dominant Mode ◽  
Microstrip Patch Antenna ◽  
Microstrip Patch ◽  
Rectangular Microstrip Patch Antenna ◽  
Simulation Results ◽  
Good Agreement

Radiations improvement in a probe fed rectangular microstrip patch antenna using linear slot etched ground plane is proposed. Conventional MPA is designed using Glass Epoxy FR4 substrate. Substrate has dielectric constant 4.4 and its thickness 1.6 mm, operated at resonant frequency 3.05 GHz. The proposed method is simple and easy to etch on a substrate. This will suppress cross-polarized (XP) radiation field only without disturbing the dominant mode and co-polarized radiations. The concept has been tested using HFSS tool and verified its results experimentally. The experimental results show a good agreement with the simulation results.

scholarly journals A Novel Multiband Fractal Antenna for Wireless Application

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Lan Wang ◽  
Jianguo Yu ◽  
Tangyao Xie ◽  
Kun Bi
Keyword(s):  
Dielectric Constant ◽  
Ring Resonator ◽  
Fractal Antenna ◽  
Dielectric Plate ◽  
Fractal Method ◽  
Feeding Method ◽  
Wireless Application ◽  
Simulation Results ◽  
5 Ghz ◽  
Good Agreement

This paper proposes a novel multiband antenna using circle and triangle fractals for wireless application. By cutting a triangle slot in the circular monopole, a novel fractal method of the circular nested triangle structure is presented. The above structure is iterated four times, which forms the proposed fractal antenna. The antenna adopts the microstrip feeding method. In order to improve out band rejection and expand bandwidth, a ring resonator is designed on the back of the dielectric plate. The designed antenna covers 1.8 GHz–2.9 GHz applied to Bluetooth, TD-SCDMA, WCDMA, CDMA2000, and LTE33-41, 3.4 GHz–4.6 GHz applied to LTE 42/43 and WiMAX, and 5 GHz–5.6 GHz applied to WLAN. The substrate is FR4 with a dielectric constant of 4.4 and a loss tangent of 0.02. The size of the fabricated antenna is 87.5 × 61 × 1.6 mm. The measured pick gain achieves 2.98 dBi, 2.58 dBi, and 3.34 dBi at 2.6 GHz, 3.8 GHz, and 5.3 GHz, respectively. The measurement and simulation results are in good agreement, which verifies the rationality of the design.

Simulation Studies on the Influence of Impact Velocity on the PELE Penetrated and Broken Reinforced Concrete

2013 ◽  
Vol 690-693 ◽  
pp. 3108-3111 ◽  
Author(s):  
Xiao Jun Ye ◽  
Zhong Hua Du ◽  
Chuan Hui Hu ◽  
Cheng Jun Song ◽  
Xiao Sheng
Keyword(s):  
Finite Element Method ◽  
Reinforced Concrete ◽  
Impact Velocity ◽  
Simulation Studies ◽  
Residual Velocity ◽  
Software Simulation ◽  
Definite Effect ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

In order to study the effect of the impact velocity for the penetrator with enhanced lateral effect (PELE) penetrating reinforced concrete (RC) targets, penetration of PELE filled nylon against RC target using the different velocity is simulated by LS-DYNA finite element method software. Simulation shows that the impact velocity have definite effect on broken RC. On condition of PELE having penetrated target, with farther increase of impact velocity, the area of PELE broken RC on the direction of decrease firstly and augmentation thereafter, the residual velocity after penetrating target is less at the same time; Take into account validity of lateral effect and general launching condition, selecting the impact velocity at the range of 800 m/s-1300 m/s is suitable for PELE broken RC. The simulation results are in good agreement with those of the experiments.

scholarly journals Molecular Simulation Study of Dielectric Constants of Pure Fluids and Mixtures

2021 ◽  
Author(s):  
Maximilian Kohns
Keyword(s):  
Dielectric Constant ◽  
Dielectric Constants ◽  
Molecular Models ◽  
Liquid Equilibrium ◽  
Pure Fluids ◽  
Wide Range ◽  
Equilibrium Data ◽  
Simulation Results ◽  
Temperature And Pressure ◽  
Good Agreement

The static dielectric constant of fluids is studied with molecular models from the literature. The employed molecular models were developed using only vapor-liquid equilibrium data. No information on the dielectric properties was used, so that the simulation results are predictions. A wide range of different fluids, from slightly to strongly polar, is investigated. Most of the studied models underestimate the dielectric constant, which can be explained by the way the models were developed. For the pure fluids dimethyl ether and acetone, the temperature and pressure dependence of the dielectric constant are also studied. A good agreement with experimental data is found. Additionally, binary mixtures are investigated. Thereby, the validity of several mixing rules for the dielectric constant is assessed.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Transport and Chronic Injuries Caused by Improper Use of Cell Phones：Evidences from 41 Studies (Preprint)

2020 ◽  
Author(s):  
Xinxi Cao ◽  
Yangyang Cheng ◽  
Chenjie Xu ◽  
Yabing Hou ◽  
Hongxi Yang ◽  
...  
Keyword(s):  
Human Body ◽  
Cell Phone ◽  
Injury Risk ◽  
Negative Impact ◽  
Mental Disease ◽  
Cell Phones ◽  
Cell Phone Use ◽  
Improper Use ◽  
Chronic Injuries ◽  
The Impact

BACKGROUND Cell phone use brought convenience to people, but using phones for a long period of time or in the wrong way and with a wrong posture might cause damage to the human body. OBJECTIVE To assess the impact of improper cell phone use on transport and chronic injuries. METHODS Studies were systematically searched in PubMed, EMBASE, Cochrane, and Web of Science up to April 4, 2019 and relevant reviews were searched to identify additional studies. A random-effects model was used to estimate the overall pooled estimates. RESULTS Cell phone users were at a higher risk for transport injuries (RR: 1.37, 95%CI: 1.221.55), long-term use of cell phones increased the transport injury risk to non-use or short-term use (RR: 2.10, 95% CI: 1.632.70). Neoplasm risk caused by cell phone use was 1.07 times that of non-use (95% CI: 1.011.14); Compared with non-use, cell phone use had a higher risk of eye disease, with a risk of 2.03 (95% CI: 1.273.23), the risk of mental disease was 1.26 (95% CI: 1.171.35), the risk of neurological disorder was 1.16 (95% CI: 1.021.32), and a pooled risk of other chronic injuries was 1.20 (95% CI: 0.981.59). CONCLUSIONS Cell phone use at inappropriate situations has a negative impact on the human body. Therefore, it is necessary to use cell phones correctly and reasonably.

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