MicroWave Journal雜志—用CST工作室套裝2016進行準確的仿真

2016-12-11 by:CAE仿真在線來源:互聯(lián)網(wǎng)

Accuracy in Simulation with CST STUDIO SUITE 2016

用CST工作室套裝2016進行準確的仿真

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工作室套裝®是面向3D電磁、電路、專業(yè)仿真軟件包?？梢栽诋a(chǎn)品研發(fā)和生產(chǎn)的各個階段用于設計,分析和優(yōu)化器件和系統(tǒng)。它已經(jīng)廣泛地用于各個工業(yè)領域:通信、電子、汽車、航空,醫(yī)療和能源等等。軟件覆蓋整個電磁頻段,提供完備的時域和頻域全波電磁算法和高頻算法。以仿真模型替代真實器件,人們可以在產(chǎn)品研發(fā)早期獲得很多信息以減少所需的樣機和縮短研發(fā)周期。使用軟件模擬可使工程師在研發(fā)早期就深入了解產(chǎn)品的運作機制,近而減少所需的測試模板及研發(fā)時間。

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.

為了使虛擬樣機切實可行,仿真軟件必須準確可靠。CST工作室套裝2016版提供了一系列的新功能使得仿真更加強大,更加精確。準確性一直是CST成功的優(yōu)勢。

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)是一項以計算在導電面上的電流分布模式來分析天線物理行為的技術。特征模式分析(CMA)可用于貼片天線的共振頻率的計算。這些信息的獲得可以幫助工程師們實現(xiàn)天線輻射的調(diào)整和輸入接口到某一輻射模式的耦合。圖一展示了特征模式分析(CMA)的一個典型應用:GSM-900PIFA天線的特征模式計算。

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.

特征模式分析技術(CMA)集成在CST工作室套裝2016版頻域矩量法求解器中(MOM Integral Equation Solver),可用于計算特征模式強度(求解在特定頻率下哪些是主要模式),遠場輻射模式,特征模式的表面電流分布。這些功能特別有利于多頻,高密度印刷天線的設計和優(yōu)化。

MicroWave Journal雜志—用CST工作室套裝2016進行準確的仿真CST電磁分析圖片1

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

圖一:用特征模式分析(CMA)計算的GSM-900 PIFA天線的前四個特征模式

Representing Reality 真實物理現(xiàn)象的準確描述

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.

仿真模型一定要能夠準確地描述實際的物理現(xiàn)象,這才是對工程師最有用的和最重要的。CST工作室套裝2016版擁有一個極為豐富的材料庫,包括高導電率有耗金屬材料,鐵氧體和非線性材料。2016版還加入了新的材料類型,包括任意轉(zhuǎn)角分層材料和網(wǎng)孔材料。對于任意板材材料均可以通過其透波率的測試或仿真數(shù)據(jù)來獲取其無需劃分網(wǎng)格的薄片精簡模型的材料屬性。這種新方法特別適用于對復合材料進行仿真,比如碳纖維,因為碳纖維的多層復合結(jié)構通常擁有很復雜的電磁屬性,且更重要的是通常復合材料廠商均不知道也無法提供材料的電磁屬性,尤其是在整個電磁兼容頻段下的特性參數(shù),所以通過實測是得到用于電磁兼容仿真所需的電磁屬性的最佳途徑。

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純瞬態(tài)場路同步協(xié)同仿真可以將非線性電路元器件直接集成到三維電磁仿真中。CST工作室套裝2016版將這個獨有的純瞬態(tài)場路同步協(xié)同仿真擴展到了瞬態(tài)電路激勵信號上,使得在CST DS中通過Transient Task也可以實現(xiàn)場路協(xié)同仿真。對于強非線性設備,對于真實信號激勵下的雜波頻譜進行分析,這是電磁兼容EMC工程師最為需要的。

Improved Meshing 更加優(yōu)化的網(wǎng)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.

仿真精度和速度極大地依賴于所用網(wǎng)格的質(zhì)量。多年來CST先后開發(fā)了很多先進的網(wǎng)格技術,包括六面體網(wǎng)格的理想邊界擬合PBA,高潔曲面元四面體網(wǎng)格的逼近真實物體的自適應網(wǎng)格,和更有效的智能網(wǎng)格引擎。CST最新加入了兩個全新的網(wǎng)格功能:混合彎曲面網(wǎng)格和移動網(wǎng)格技術。積分方程求解器在大面積薄金屬結(jié)構的表面網(wǎng)格劃分上非常高效,如反射面天線和汽車車體。

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工作室套裝中,表面網(wǎng)格采用三角形和四邊形的混合網(wǎng)格可以準確地描述模型的曲面(見圖二)?；旌暇W(wǎng)格技術比傳統(tǒng)方式可以大大地減少網(wǎng)格數(shù)量,進而極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.

移動網(wǎng)格優(yōu)化最有利于對高敏感結(jié)構的設計和調(diào)節(jié),通常濾波器結(jié)構均采用四面體網(wǎng)格來仿真。在優(yōu)化過程中,每一步模型結(jié)構均有所變化,相應的網(wǎng)格也就需要變化。CST工作室套裝2016版采用新的移動網(wǎng)格技術可以不重新生成網(wǎng)格,而是在原有的網(wǎng)格上進行微移少量網(wǎng)格節(jié)點來逼近新結(jié)構。這樣可以節(jié)約網(wǎng)格劃分的時間,而且準確性也因為減少了全新劃分網(wǎng)格所帶來的數(shù)值噪聲而得到了提高。

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.
網(wǎng)格引擎的其他改進還包括更智能的網(wǎng)格自適應、用于移動物體的滑動網(wǎng)格和與網(wǎng)格生成無關的參數(shù)掃描。

MicroWave Journal雜志—用CST工作室套裝2016進行準確的仿真CST電磁分析圖片2

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

圖二:雙極偶子拋物面天線的混合曲面元網(wǎng)格

High-Performance Computing 高性能計算

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.

大型復雜的模型通常會超出了一般計算機的硬件能力,高性能計算可以縮短技術時間。CST工作室套裝支持多種HPC技術:共享內(nèi)存的多線程和多芯片并行計算OpenMP、硬件加速卡(英偉達GPU卡或英特Phi卡)、多節(jié)點集群MPI并行計算。

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工作室套裝軟件已通過英特爾集群計算(Intel® Cluster Ready)認證。目前可以在集群上提供純瞬態(tài)場路同步協(xié)同仿真。此外,CST高頻漸近求解器也支持GPU加速,使得雙站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.

多年來CST工作室套裝主要在Linux集群計算環(huán)境下提供批處理形式的仿真。隨著近年來Linux被越來越多地用于交互式,CST工作室套裝2016版開始提供Linux下的互動交互工作模型,不但包含計算本身,而且包含前后處理,即整個軟件可以在Linux環(huán)境下與Windows一樣地進行使用。