首页/文章/ 详情

cst出SAR结果的过程

3月前浏览2298



     

SAR即英语“Specific Absorption Rate”的缩写,意为电磁波吸收比值或比吸收率。是手机或 无线产品之电磁波能量吸收比值,其定义为:在外电磁场的作用下,人体内将产生感应电磁场。



 
 




简单记录下用cst出SAR结果的过程


1、field monitor里设置SAR





2、仿真完成之后,在post-processing中  result templates tools---选择2d 3d场结果再选择sar



3、计算sar








     

        SAR值一般指手机产品中电磁波所产生的热能,它是对人体产生影响的衡量数据,单位是W/Kg(瓦/公斤)。美国联邦传播委员会(FCC)所公布行动电话的安全标准值为1.6,因此只要行动电话的SAR值在1.6以下,都是在安全标准内的产品。

        SAR值表示行动电话的热能会对人体会造成多少影响,数值越大,表示对人体的影响越大;反之则影响较小。


ps:cst help文档中关于SAR的描述  
 

Definition

The Specific Absorption Rate (SAR) is defined as the time derivative of the incremental energy (dW ) absorbed by (dissipated in) an incremental mass (dm) contained in a volume element (dV) of a given mass density ( r ).

The SAR value is expressed in units of watts per kilogram (W/kg). The Power Loss Density (PLD) value is expressed in units of watts per cubic meter (W/m^3).




SAR calculation

CST MICROWAVE STUDIO offers whole-body-averaged and local SAR values:

Whole-body-averaged SAR: The value is obtained by dividing the total power absorbed in the human body by the full body weight. It is also possible to define a sub volume by picks or by numbers.

Local SAR: SAR is given as a numerical value per volume element and becomes a space distribution function. For this function, the mass mean value in arbitrary tissue volume is called local SAR. Typical local SAR values are averaged in tissue masses of around 10g specified by the Telecommunication Technology Council Agenda No. 89 and CENELEC 1995, whereas the value of 1g is adopted by ANSI/IEEE C95.1-1992 of the United States. A cuboid averaging volume is used.

SAR result file

The SAR results file can be accessed in the SAR calculation dialog and by clicking Edit->Info while the SAR field result is selected in the Navigation Tree. It contains the following:

Power scaling: Indicates if the whole SAR result is rescaled to a user defined power.

Stimulated Power: Input power of the SAR calculation.

Accepted Power: Input power of the SAR calculation without reflection losses.

Sys.Stimulated Power: Stimulated power of the circuit excitation (if used).

Sys.Accepted Power: Accepted power of the circuit excitation (if used).

AR filter results: Indicates the availability of AR filter balance results.

Powerloss density monitor used: Name and frequency of the power loss density monitor used to calculate this SAR results.

Average cell mass: The average mass of all grid cells which contain material with mass density (rho) greater zero.

Averaging method: The method used to calculate spatial averaged SAR if not Point SAR has been calculated.

Averaging mass / Averaging volume: The mass of the averaging cube used for spatial averaging. If "Constant volume" has been choosen as averaging method, the volume of the cube is given. If Point SAR has been calculated, zero is output.

Entire Volume / Selected Volume: The following values apply to the entire calculation domain or the selected subvolume respectively.

Min / Max / Volume: The spatial dimensions and the volume of the calculation domain or subvolume respectively.

Absorbed power: The total power absorbed in biological tissue and other lossy normal material. Please note that lossy metal is not included.

Tissue volume / Tissue mass: The volume and mass of the biological tissue contained in the entire calculation domain or subvolume respectively.

Tissue power: The power absorbed in biological tissue (all material with mass density greater zero).

Average power: The average power absorbed in biological tissue (all material with mass density greater zero).

Total SAR: The tissue power divided by the tissue mass.

Max. point SAR: The maximum point SAR of all grid cells. For each grid cell, its point SAR is calculated by its absorbed power divided by its mass.

Maximum SAR: The maximum of the spatially averaged SAR for the given averaging mass. For point SAR calculations, the averaging mass is denoted as zero.

Maximum at: The spatial position of the above maximum.

Avg.vol.min / Avg.vol.max: Gives the dimensions and position of the averaging cube used for the above maximum. Note that if statistics for both the entire and the selected volume are output, the averaging cube is only output for the selected volume.

Largest valid cube: Edge length of the largest valid averaging volume.

Smallest valid cube: Edge length of the smallest valid averaging volume.

Avg.Vol.Accuracy: Volume accuracy of the averaging cubes used for in SAR calculation.

Calculation time: Time used for the SAR calculation.

TLM SAR Calculation

The TLM solver has a legacy built-in SAR calculator that calculates point SAR and SAR averaged over 1g and 10g when a Power loss density field monitor has been defined. This calculation is not compliant with recent standards. The average SAR calculated for a cell is considered invalid if the discretized averaging region that is grown around that cell includes more than 10% air or the centre of every cell on any single face of the averaging region is completely in air. If the calculated average SAR for a cell is considered invalid then the maximum SAR calculated for any cell whose averaging region encloses the invalid cell will be taken instead. PBA is not considered when calculating the volume of each cell in this averaging region, whole Cartesian cells are assumed.




来源:灵境地平线
UMCSTMETA
著作权归作者所有,欢迎分享,未经许可,不得转载
首次发布时间:2024-08-04
最近编辑:3月前
周末--电磁仿真
博士 微波电磁波
获赞 23粉丝 21文章 163课程 0
点赞
收藏
作者推荐

计算电磁学三大算法的开源代码

计算电磁学包含了广泛的应用领域,包括天线、纳米光子学、太阳能电池、超材料、激光等等。在这些不同的领域中,也有许多方法来进行所需的计算。电磁模拟有三种主要的数值方法:FDTD,FEM和MOM。每种方法都最适合特定的情况,各有优缺点。在这篇文章中,汇总这些方法的一些最好的开源实现的参考资料(附链接)。三大算法简介FDTD算法:采用差分直接离散时域Maxwell方程,电磁场的求解基于时间步的迭代,无需存储全空间的电磁场信息,内存消耗较小,同时采用立方体网格和差分算法,网格形式和算法均十分简单,计算速度也贼快,基于时域算法,特别适合“宽带问题”的求解。但是,简单的立方体方体网格带来的弊端就是模型拟合精度较低,对于含有精细结构的模型,计算精度较低,同时基于“微分方程”,计算区域需要设置截断。FDTD比较适合于不含有较多精细结构的电大尺寸模型的电性能计算以及宽带问题的计算;FEM算法:采用四面体网格对目标进行离散,拟合精度比FDTD算法更高,计算精度也要明显优于FDTD算法。但是,FEM基于频域/微分算法,需要同时对整个区域内的电磁场信息进行求解和存储,内存消耗大,计算速度慢,计算模型的电尺寸也相对较小。FEM主要适合于微波电路器件,天线等目标“辐射问题”的精确计算;MoM算法:通过“场-源关系”,将“场”的求解问题转化为“源”求解问题,采用的基函数“格林函数”天然满足辐射条件,无需设置截断,计算精度高,同时矩阵的计算采用直接计算,不存在收敛性的问题,同时由于网格的剖分仅存在于目标体表面或内部,未知量数目大幅降低,矩阵规模小于FDTD和FEM,但是由于“源”之间均存在耦合,因此矩阵为“稠密”矩阵,计算复杂度大,计算速度慢。MoM主要适合于含有精细结构的电小尺寸目标“散射问题”的精确计算。三大算法的开源代码1、三大算法的区别2、fdtd最好的开源代码Meep.DevelopedatMIT,MeepisahighlyefficientFDTDpackage,scriptableinPython,SchemeorcallablefromC++APIs.ItisparallelizedwithMPI,anditincludesalibrarywithsupportforavarietyofmaterialtypes.https://meep.readthedocs.io/en/latest/Meep由麻省理工学院开发,是一个高效的FDTD包,可以用Python、Scheme编写脚本,也可以从C++API调用。它与MPI并行,并包含一个支持多种材料类型的库。gprMax.DevelopedattheUniversityofEdinburgh,gprMaxwasdesignedformodellingGroundPenetratingRadar(GPR)butcanalsobeusedtomodelelectromagneticwavepropagationformanyotherapplications.gprMaxiscommand-linedrivensoftwarewritteninPython,withperformance-criticalpartswritteninCython/OpenMP.https://www.gprmax.com/gprMax由爱丁堡大学开发,旨在为探地雷达(GPR)建模,但也可用于许多其他应用的电磁波传播建模。gprMax是用Python编写的命令行驱动软件,性能关键部分用Cython/OpenMP编写。OpenEMS.DevelopedattheUniversityofDuisburg-Essen,andparallelizedwithMPI.MatlaborOctaveareusedasascriptinginterfaces.http://openems.de/index.php/Tutorials由杜伊斯堡-埃森大学开发,并与MPI并行。Matlab或Octave用作脚本接口。3、FEM最好的开源代码FEniCS.FEniCSisapopularopen-sourceLGPLv3-licencedsoftwarepackageforsolvingpartialdifferentialequations(PDEs).Itfeatureshigh-levelPythonandC++interfaces,andcanberuninhigh-performanceclusters.Togetstarted,visittheFEniCSTutorialwhichincludesanexampleinmagnetostatics,orcheckouttheofficialDiscourseforum.https://fenicsproject.org/FEniCS是一个流行的开源LGPLv3许可软件包,用于求解偏微分方程(PDE)。它具有高级Python和C++接口,可以在高性能集群中运行。要开始使用,请访问FEniCS教程,其中包括静磁学示例,或查看官方话语论坛。ElmerFEM.Anopen-sourceFiniteElementSolver,dealingwithmultiphysicalsimulations.Built-inElectromagneticsSolversincludemagnetostatic,electrostaticandwave-equationsolvers.SeetheElmerModelsManualformoreinformation.ElmerhasaGUI,acommand-lineinterface,andaPythonwrapperpyelmer.http://www.elmerfem.org/blog/一个开源的有限元求解器,处理多物理模拟。内置的电磁学求解器包括静磁、静电和波动方程求解器。有关更多信息,请参阅Elmer型号手册。Elmer有一个GUI、一个命令行界面和一个Python包装器pyelmer。FreeFEM.FreeFEMisanopen-sourceLGPLv3-licencedPDEsolverrelyingonitsownprogramminglanguage.FreeFEMoffersalargelistoffiniteelements.Pre-builtphysicsforElectromagneticsimulationsincludeMagnetostaticsandElectrostaticsonly.FreeFEM.https://freefem.org/FreeFEM是一个开源的LGPLv3许可的PDE求解器,依赖于自己的编程语言。FreeFEM提供了大量的有限元列表。用于电磁模拟的预构建物理学仅包括静磁学和静电学。4、MOM最好的开源代码Bempp.Bemppisanopen-source,MITlicenced,computationalboundaryelementplatformtosolveelectrostatic,acousticandelectromagneticproblems.Bemppusesjust-in-timecompiledOpenCLorNumbakernelstoassembleBEMoperatorsinCPUsorGPUs.FeaturesincludeaPythoninterface,FastMultipoleMethodaccelerationviaExafmm-t,andcoupledFEM/BEMcomputationsviainterfacestoFEniCS.http://bempp.com/Bempp是一个开源的、获得麻省理工学院许可的计算边界元平台,用于解决静电、声学和电磁问题。Bempp使用实时编译的OpenCL或Numba内核在CPU或GPU中组装BEM运算符。功能包括Python接口、通过Exafmm-t进行快速多极方法加速,以及通过FEniCS接口进行FEM/BEM耦合计算。PumaEMisanopen-source(GPLv3licensed)MethodofMomentsimplementationforElectromagnetics,acceleratedwiththeMultilevelFastMultipoleMethod,andparallelizedviaMPI.https://github.com/Gjacquenot/Puma-EMPumaEM是一种用于电磁学的开源(GPLv3许可)矩量法实现,采用多级快速多极方法加速,并通过MPI并行化。NEC-2.AclassicalcodebyLLNLrewritteninC++,targetedatwireandsurfaceantennasimulation.https://github.com/tmolteno/necppLLNL用C++重写的经典代码,针对有线和地面天线仿真。参考:Open-SourceElectromagneticSimulation:FDTD,FEM,MoM(epsilonforge.com)缘起“收敛性”——Maxwell方程与求解"target="_blank">来源:灵境地平线

未登录
还没有评论
课程
培训
服务
行家
VIP会员 学习 福利任务 兑换礼品
下载APP
联系我们
帮助与反馈