MicroWave Journal杂志—用CST工作室套装2016进行准确的仿真

2016-12-11 by:CAE仿真在线来源:互联网

Accuracy in Simulation with CST STUDIO SUITE 2016

用CST工作室套装2016进行准确的仿真

CST® STUDIO SUITE® is an electromagnetic simulation tool used to design, analyze and optimize devices and systems at all stages of the development process. It is used in industries as diverse as electronics, automotive, aerospace, medical and energy, and covers the electromagnetic spectrum from statics to optics. By replacing physical prototypes with virtual ones, engineers can study how their products work at the earliest stages of design and reduce the number of physical models that need to be constructed.

CST工作室套装®是面向3D电磁、电路、专业仿真软件包。可以在产品研发和生产的各个阶段用于设计,分析和优化器件和系统。它已经广泛地用于各个工业领域:通信、电子、汽车、航空,医疗和能源等等。软件覆盖整个电磁频段,提供完备的时域和频域全波电磁算法和高频算法。以仿真模型替代真实器件,人们可以在产品研发早期获得很多信息以减少所需的样机和缩短研发周期。使用软件模拟可使工程师在研发早期就深入了解产品的运作机制,近而减少所需的测试模板及研发时间。

For virtual prototyping to be a viable option, the simulation tools need to be accurate without sacrificing performance. For this reason, the release of CST STUDIO SUITE 2016 builds on the success of previous versions with a range of new features that make the analysis of systems more powerful while building on CST’s reputation for accuracy.

为了使虚拟样机切实可行,仿真软件必须准确可靠。CST工作室套装2016版提供了一系列的新功能使得仿真更加强大,更加精确。准确性一直是CST成功的优势。

Characteristic Mode Analysis 特征模式分析

Characteristic Mode Analysis (CMA) is a technique developed to provide physical insight into the behavior of a conducting surface by calculating the current-modes that it can support. For example, CMA can be used on a patch antenna to identify the resonant frequencies of the patch. This allows engineers to tune the antenna to the correct frequencies and determine where to place the feed to couple into a particular radiating mode. Figure 1 demonstrates one typical application of CMA to calculate the modes on a GSM-900 PIFA antenna.

特征模式分析(CMA)是一项以计算在导电面上的电流分布模式来分析天线物理行为的技术。特征模式分析(CMA)可用于贴片天线的共振频率的计算。这些信息的获得可以帮助工程师们实现天线辐射的调整和输入接口到某一辐射模式的耦合。图一展示了特征模式分析(CMA)的一个典型应用:GSM-900PIFA天线的特征模式计算。

The CMA tool is integrated into the method-of-moments (MOM) Integral Equation Solver in CST STUDIO SUITE, and calculates the modal significance (a measure of which modes are dominant at a particular frequency), far field radiation pattern and surface current distribution associated with each mode, with automatic mode-tracking. These features are particularly useful for analyzing and optimizing printed antennas, which often have to be compact and multiband.

特征模式分析技术(CMA)集成在CST工作室套装2016版频域矩量法求解器中(MOM Integral Equation Solver),可用于计算特征模式强度(求解在特定频率下哪些是主要模式),远场辐射模式,特征模式的表面电流分布。这些功能特别有利于多频,高密度印刷天线的设计和优化。

MicroWave Journal杂志—用CST工作室套装2016进行准确的仿真CST电磁分析图片1

Figure 1 The first four modes on a GSM-900 PIFA antennacalculated with CMA.

图一:用特征模式分析(CMA)计算的GSM-900 PIFA天线的前四个特征模式

Representing Reality 真实物理现象的准确描述

To be useful to engineers, a simulation needs to accurately represent the physical system. CST STUDIO SUITE offers an extensive library of material types, such as lossy metals, ferrites and nonlinear materials. The 2016 version adds new advanced types, including arbitrary graded materials and perforated materials. Measured or simulated data can now be used to generate realistic thin panel materials to be included in models. This is particularly useful for modeling composite materials, such as carbon fiber, which have complex electromagnetic properties due to their structure.

仿真模型一定要能够准确地描述实际的物理现象,这才是对工程师最有用的和最重要的。CST工作室套装2016版拥有一个极为丰富的材料库,包括高导电率有耗金属材料,铁氧体和非线性材料。2016版还加入了新的材料类型,包括任意转角分层材料和网孔材料。对于任意板材材料均可以通过其透波率的测试或仿真数据来获取其无需划分网格的薄片精简模型的材料属性。这种新方法特别适用于对复合材料进行仿真,比如碳纤维,因为碳纤维的多层复合结构通常拥有很复杂的电磁属性,且更重要的是通常复合材料厂商均不知道也无法提供材料的电磁属性,尤其是在整个电磁兼容频段下的特性参数,所以通过实测是得到用于电磁兼容仿真所需的电磁属性的最佳途径。

Nonlinear circuit elements can be integrated directly into 3D EM simulations through CST’s True Transient EM/Circuit Co-Simulation. In CST STUDIO SUITE 2016, the link between circuit and EM simulation is strengthened further by the new Combine Results in Transient Task feature. This allows the results of a 3D simulation to be included in a transient circuit simulation with no post-processing required. This is a feature that will benefit EMC engineers, for example, who need to simulate the behavior of electronic systems affected by pulses or realistic digital signals.

CST纯瞬态场路同步协同仿真可以将非线性电路元器件直接集成到三维电磁仿真中。CST工作室套装2016版将这个独有的纯瞬态场路同步协同仿真扩展到了瞬态电路激励信号上,使得在CST DS中通过Transient Task也可以实现场路协同仿真。对于强非线性设备,对于真实信号激励下的杂波频谱进行分析,这是电磁兼容EMC工程师最为需要的。

Improved Meshing 更加优化的网格

The accuracy and performance of a simulation are heavily dependent on the quality of the mesh which describes the structure. Achieving very high mesh quality has previously led to innovations including PERFECT BOUNDARY APPROXIMATION (PBA)® for hexahedral meshes, True Geometry Approximation for curved tetrahedral meshes, and intelligent mesh engines for more efficient discretization. Two important new features have now been added to the repertoire: hybrid curved surface meshing and moving mesh optimization. The surface mesh used by the Integral Equation Solver is very efficient for structures such as reflector antennas and vehicle bodies, which are constructed from large, thin sheets of metal.

仿真精度和速度极大地依赖于所用网格的质量。多年来CST先后开发了很多先进的网格技术,包括六面体网格的理想边界拟合PBA,高洁曲面元四面体网格的逼近真实物体的自适应网格,和更有效的智能网格引擎。CST最新加入了两个全新的网格功能:混合弯曲面网格和移动网格技术。积分方程求解器在大面积薄金属结构的表面网格划分上非常高效,如反射面天线和汽车车体。

With the new version, the surface mesh can now use a hybrid combination of triangular and quadrilateral mesh cells, and these polygons can be curved and conformal to the structure (see Figure 2). This means that a structure can be discretized very accurately with fewer mesh cells compared to traditional meshes, which can accelerate simulation significantly.

在新版的CST工作室套装中,表面网格采用三角形和四边形的混合网格可以准确地描述模型的曲面(见图二)。混合网格技术比传统方式可以大大地减少网格数量,进而极大地提高了仿真速度。

Moving mesh optimization is most useful when designing and tuning highly sensitive structures such as filters, which are usually described using a tetrahedral mesh. At each step of an optimization of such a structure, the model geometry changes slightly, which means that the mesh needs to change as well. Instead of recalculating the mesh from scratch, CST STUDIO SUITE 2016 can instead adjust the previous mesh to fit the new structure. This speeds up the meshing process, and can also improve accuracy by reducing the noise associated with repeated mesh generation.

移动网格优化最有利于对高敏感结构的设计和调节,通常滤波器结构均采用四面体网格来仿真。在优化过程中,每一步模型结构均有所变化,相应的网格也就需要变化。CST工作室套装2016版采用新的移动网格技术可以不重新生成网格,而是在原有的网格上进行微移少量网格节点来逼近新结构。这样可以节约网格划分的时间,而且准确性也因为减少了全新划分网格所带来的数值噪声而得到了提高。

A range of other improvements to the mesh engines include more intelligent mesh adaptation, sliding meshes for moving part simulation, and the ability to define mesh-independent parameters.
网格引擎的其他改进还包括更智能的网格自适应、用于移动物体的滑动网格和与网格生成无关的参数扫描。

MicroWave Journal杂志—用CST工作室套装2016进行准确的仿真CST电磁分析图片2

Figure 2 Hybrid curved mesh on a parabolicreflector with double dipole splashplate feed.

图二:双极偶子抛物面天线的混合曲面元网格

High-Performance Computing 高性能计算

For very large or complex simulations that approach the limits of conventional computing hardware, high-performance computing (HPC) can offer significant time advantages. CST STUDIO SUITE supports multithreading and multi-CPU parallelization in shared memory environments, hardware acceleration (Nvidia® Tesla® GPU and Intel® Xeon Phi®), and cluster computing using distributed computing and MPI.

大型复杂的模型通常会超出了一般计算机的硬件能力,高性能计算可以缩短技术时间。CST工作室套装支持多种HPC技术:共享内存的多线程和多芯片并行计算OpenMP、硬件加速卡(英伟达GPU卡或英特Phi卡)、多节点集群MPI并行计算。

It was recently certified as Intel® Cluster Ready, and its cluster computing capabilities have been expanded with the ability to perform True-Transient EM/Circuit Co-Simulation on MPI clusters. In addition, the Asymptotic Solver now also supports GPU acceleration, which can significantly speed up bistatic radar simulations and other simulations with large numbers of observation points.

CST工作室套装软件已通过英特尔集群计算(Intel® Cluster Ready)认证。目前可以在集群上提供纯瞬态场路同步协同仿真。此外,CST高频渐近求解器也支持GPU加速,使得双站RCS仿真速度得以大大的提高。

Linux

CST has supported Linux in HPC compute cluster environments for many years. This allowed simulation jobs to run in batch mode without user interaction. However, Linux-based operating systems are now becoming increasingly common for workstations, and CST STUDIO SUITE 2016 can now be used interactively directly on a Linux machine. This includes the powerful 3D modeling tools and results viewer, greatly increasing the number of tasks that can be performed entirely in a Linux environment.

多年来CST工作室套装主要在Linux集群计算环境下提供批处理形式的仿真。随着近年来Linux被越来越多地用于交互式,CST工作室套装2016版开始提供Linux下的互动交互工作模型,不但包含计算本身,而且包含前后处理,即整个软件可以在Linux环境下与Windows一样地进行使用。