CST系統級RS模擬（一）——天線建模

發佈留言 / Useful / 作者: WU AMY

輻射抗擾度（Radiate Susceptibility）：又稱輻射敏感度，是基本的EMS測試項目之一。在該試驗模擬設備遭受射頻輻射干擾的情況下，抵抗外部電磁干擾的一種能力。通常，民用電子設備參考國際標準IEC 61000-4-3。CST的RS模擬的干擾源可以使用平面波或是3D天線模型，這裡我們介紹使用3D天線來模擬RS模擬測試的方法。這種方法更貼近實測場景，模擬精度更高。

利用CST Antenna Magus創建LPDA天線模型

RS測試頻段80MHz-6GHz，對於不同頻段，需要採用不同類型的天線。本次我們重點介紹的是80-1G頻段採用LPDA天線的建模方法。在開始建模之前，我們需要先初步了解LPDA天線的規格參數，下圖是典型的LPDA天線的規格。

A technical illustration of the CBL 6143A vertical antenna mounted on a BTP 6020A tripod. The left side of the image lists technical specifications, including frequency range, typical gain, impedance, maximum continuous power, connector type, VSWR, dimensions, and weight. On the right side, there are diagrams of the antenna with dimensions and typical E field polar patterns for frequencies 30 MHz, 1000 MHz, and 3000 MHz. The polar patterns include horizontal and vertical orientations, shown in circular plots.

已知LPDA天線規格後，我們開始利用CST Antenna Magus進行建模操作。Antenna Magus是CST專有天線庫，包含了將近400種不同類型的天線，可以根據客戶指定的規格，快速實現天線的3D建模。

The image shows a section of a software interface labeled 'Modules and Tools.' There are six icons representing different modules or tools within the software. The icons and their labels from left to right are: 1. 3D Simulation 2. Circuits & Systems 3. PCBs & Packages 4. Antenna Magus (highlighted with a red box) 5. Filter Design 6. CST Chip. The highlighted module, 'Antenna Magus,' is likely a tool used for designing and analyzing antennas. This image is relevant for users who are interested in electromagnetic simulation and design tools.

打開Antenna Magus之後，在Keywords裡面輸入EMC，選擇LPDA天線。

The image shows a screenshot of a software interface, likely related to antenna design or electromagnetic compatibility (EMC) applications. The interface includes several sections: 1. Specification Panel: On the left side, there are options for specifying values such as Frequency Bands, Radiation Pattern, and Spatial Limitations. These sections are collapsed. 2. Keywords Section: Below the specification panel, there is a section for entering keywords. The keyword 'emc' is entered in this section. 3. Search Results Panel: On the right side, there is a panel displaying search results for the keyword 'emc'. The result shows 'EMC' with a description 'Antennas commonly used in electromagnetic compatibility applications'. Below this, it lists 'EMC wire biconical antenna' with a note that it is 'already added'. 4. Toolbar and Menu: At the top, there are various menu options such as File, Home, Libraries, Toolbox, and others, along with icons for different actions like opening, saving, and exporting files. 5. Icons at the Bottom: There are several icons at the bottom of the interface, possibly representing different types of antennas or components. This image is relevant for users working with antenna design or EMC applications, as it shows how to search for and select specific types of antennas based on keywords.

The image shows a diagram of an antenna labeled 'LPDA-Bow-tie hybrid with square boom'. The antenna appears to be a hybrid design combining elements of a Log-Periodic Dipole Array (LPDA) and a Bow-tie antenna, with a square boom structure. This type of antenna is interesting and relevant for its potential applications in wideband communication systems due to its hybrid design, which may offer improved performance characteristics such as bandwidth and gain.

在Specification裡面設定天線規格參數，主要包括頻寬、增益等參數，可以參考前面的天線規格來設定。

Screenshot of a software interface used for antenna design and electromagnetic simulation. The interface is divided into several sections: 1. Top Menu Bar with options such as File, Home, Libraries, Toolbox, Export, and View Tools. Icons include Find, Design, Array Synthesis, Model Export, Info Browser, Compare, Specification Disabled, Edit Specification, New Design, Design Tweak, Estimate Performance, Calculate NFS now, and Delete Design/Tweak. 2. Left Panel titled 'Specification' showing 'Prototype Designs and Tweaks,' with input fields for Port Impedance (Rin) set to 50 Ω and Other Properties (po) set to 'Optimum performance.' Buttons for New Design and Design. 3. Right Panel labeled 'Feed detail' with a sketch of an antenna, showing labels for Feed point, Sb, and Wb. 4. Bottom Panel titled 'Value Comparison - Objectives' comparing design values, showing Primary Design with a minimum frequency of 30 MHz.

設定規格參數後，點選Design產生3D模型，然後點選Estimate Performance進行效能評估。可以看到天線的增益、方向圖等結果。

The image contains several elements related to the design and performance analysis of an antenna. The model preview shows a 3D model of the antenna with dimensions labeled Z: 1.553 m and X: 1.405 m. The graph titled 'Far Field vs Frequency' shows the Gain (Total) in dBi on the y-axis and frequency in MHz on the x-axis, indicating how the gain varies with frequency, peaking around 10 dBi. A 3D plot titled 'Design 1 [30 MHz]' shows the total gain in dBi with a color scale ranging from -5.212 dBi to 19.25 dBi, representing the radiation pattern at 30 MHz. The design guidelines text provides options for 'optimum performance' or 'optimum arrangement' for the antenna design.

接下來可以輸出天線模型到CST Component Library，方便未來調用。

The image shows a software interface related to exporting models. The interface includes several sections: 1. Export Models Section with two models listed. Model 1 displays a warning message about isolated parameter sets failing validation and describes it as a parametric cylinder model with a square boom using the T-solver. Model 2 has no additional information. 2. Export Model Options with a dropdown menu for exporting model options. 3. Parameters - Design 1 Section showing parameters like fmin (30 MHz) and fmin_lpda (230 MHz). 4. Model Name Section listing various parameters including frequency_minimum, frequency_minimum_lpda, frequency_maximum, num_elements, load_impedance, boom_spacing, and boom_width. 5. Information Section with partially visible text that is unreadable. This image is relevant for users working with parametric models and exporting them in CST software.

可以看到，剛剛產生的LPDA模型已經載入到CST Component Library裡面。

The image shows a screenshot of a software interface, likely for a simulation or design tool. The left sidebar contains various menu options such as 'Save,' 'Save As,' 'Save All,' 'Preview and Organize,' 'Open,' 'Close,' 'Project,' 'New and Recent,' 'Component Library,' 'Manage Libraries,' 'Print,' and 'Help.' The main section of the interface displays a component library with tabs for 'All Components,' 'Examples,' and 'Tutorials.' Two components are visible: one labeled 'antenna_EMC_30M_1G' by 'MZU3' and another labeled 'Bulk Current Injection' by 'Dassault Systemes.' The 'antenna_EMC_30M_1G' component is described as 'Balun, Ultra-wideband, Array element,' and the 'Bulk Current Injection' component is tagged with 'EMC.'

直接呼叫模型庫的文件，產生3D天線模型，進行下面的模擬。

The image shows a 3D model of a Yagi-Uda antenna, commonly used for radio and television reception. The model includes elements such as the driven element, reflector, and multiple directors, positioned within a coordinate system with labeled axes (U, V, W). Various circular markers with arrows indicate the direction of the electromagnetic field or current distribution on the antenna elements. The background grid helps visualize the spatial arrangement and alignment of the antenna components. This image is relevant for understanding the design and analysis of Yagi-Uda antennas, known for their directional properties and gain.

原文轉載來自: 周明 – CST系统级RS仿真（一）——天线建模

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