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。
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.