Schematic diagram of a mechanical or electronic system. The system consists of interconnected components in yellow and gray colors, against a blue background. Yellow components appear to be central connectors or junctions, while gray components are conduits or pathways leading to other parts of the system. Multiple pathways branch out from the central yellow structure, indicating a complex network of connections. Text in Chinese at the bottom right reads 'CST仿真专家之路,' translating to 'CST Simulation Expert Road.' The diagram represents a technical system layout, likely for educational or professional engineering purposes.

CST毫米波雷達模擬解決方案介紹（四）

發佈留言 / Useful / 作者:

本期我們介紹毫米波雷達天線的饋電網路模擬。如上圖所示，這是一個常見的並聯饋電結構，採用T 型分支結構。天線工程師在設計饋電網路時，重點要考慮兩方面的指標：一是輸入端到多個輸出端的功率分配；二是確保多個輸出埠的相位盡量一致。

以下介紹CST針對饋電網路的快速設計、最佳化流程，具體方法如下：

1.在DS工作室的原理圖介面，利用Microstrip直接進行微帶線設計，每一小段的微帶線的長和寬都設定成參變量，方便後續的最佳化處理，如下圖所示。

The image shows a graphical user interface (GUI) of a software tool used for designing and optimizing microwave circuits. The left side of the image displays a menu with different categories: Microstrip, Stripline, Waveguide, and Circuit Elements. Below the menu, there are various icons representing different circuit elements, such as microstrip lines, bends, and other components. The right side of the image shows a schematic diagram labeled 'Feed Optimization' with a 3D representation of a microstrip at the top. The schematic includes multiple ports labeled Port1, Port2, Port3, Port4, Port5, and Port6, connected by various microstrip elements. The connections between the ports are represented by blue lines, and the microstrip elements are depicted in red and yellow. This image is interesting and relevant because it illustrates the process of designing and optimizing microwave circuits using microstrip technology. The software tool allows users to create and simulate complex circuit layouts, which is essential for developing efficient and high-performance microwave systems.
A screenshot of a software interface showing a tab labeled 'Schematic' under the section 'Block Parameter List (MSLINE10).' The interface has two tabs: 'General' and 'Settings.' The 'General' tab is selected, displaying a table with three columns: 'Name,' 'Expression,' and 'Value.' The table lists parameters such as Length (0.66328109179003), Width (0.20085320966005), Height (0.005), and Thickness (0.000035).

2.創建一個S-parameters Task，從S參數的模擬結果來看，微帶功分網路並不符合陣列設計的功率分配要求。

A graph showing the S-Parameters (Magnitude) in decibels (dB) versus Frequency in GHz. The x-axis represents the frequency range from 76 GHz to 77.8 GHz, and the y-axis represents the magnitude in dB ranging from -24 dB to -4 dB. The graph includes six different S-parameters: S1,1, S2,1, S3,1, S4,1, S5,1, and S6,1, each represented by different colored lines. The legend on the graph provides specific values for each S-parameter at a particular frequency, including -21.414227 dB for S1,1, -8.2045003 dB for S2,1, -5.9662428 dB for S3,1, -7.7559428 dB for S4,1, -5.9662428 dB for S5,1, and -8.2045003 dB for S6,1. The graph is relevant for analyzing the performance of a system in terms of its S-parameters over a specified frequency range.

3.接下來我們利用CST的優化器對饋電網路的尺寸進行最佳化。點選Optimizer，勾選要最佳化的參變量，選擇S11、S21、S31、S41、S51、S61作為最佳化目標，Target裡面分別輸入-30、-8.81、-6.25、-5.8、-6.25、-8.81，單位dB。這裡輸入的S參數目標值是根據功率分配指標換算的結果，具體換算過程大家可以自行查找，此處不再贅述。

Screenshot of an optimization software interface labeled 'Optimizer' window. The interface has tabs like 'Settings,' 'Goals,' and 'Info.' The 'Settings' tab displays algorithm settings for the 'Trust Region Framework' algorithm with parameters and their min/max values. The 'Goals' tab lists goals with details like IDs, types, operators, targets, ranges, and weights. The highlighted section in 'Goals' tab shows a tapering process with specific target values. Relevant text: Algorithm: Trust Region Framework, Number of evaluations: 131 (solver: 130, reloaded: 1), Initial goal function value = 520.597983752 (reloaded), Best goal function value = 0.0034504280101, Last goal function value = 0.0034504280101. Parameters: DS_L1 (Min = 0.25, Max = 1), DS_L2 (Min = 0.175, Max = 0.5), DS_L3 (Min = 0.25, Max = 1), DS_La1 (Min = 0.175, Max = 0.5), DS_La2 (Min = 0.175, Max = 0.5), DS_L4 (Min = 0.175, Max = 0.525), DS_L5 (Min = 1.5, Max = 2), DS_W1a (Min = 0.075, Max = 0.15), DS_W2 (Min = 0.203, Max = 0.25), DS_W3 (Min = 0.1, Max = 0.3), DS_W4a (Min = 0.075, Max = 0.225), DS_W5 (Min = 0.075, Max = 0.15). Goals: ID 1 (Type = 1DC:\\SPara1\\S-Parameters\\S1,1, Operator = <, Target = -30, Range = 77, Weight = 1.0), ID 2 (Type = 1DC:\\SPara1\\S-Parameters\\S2,1, Operator = =, Target = -8.81, Range = 77, Weight = 1.0), ID 3 (Type = 1DC:\\SPara1\\S-Parameters\\S3,1, Operator = =, Target = -6.25, Range = 77, Weight = 1.0), ID 4 (Type = 1DC:\\SPara1\\S-Parameters\\S4,1, Operator = =, Target = -5.8, Range = 77, Weight = 1.0), ID 5 (Type = 1DC:\\SPara1\\S-Parameters\\S5,1, Operator = =, Target = -6.25, Range = 77, Weight = 1.0), ID 6 (Type = 1DC:\\SPara1\\S-Parameters\\S6,1, Operator = =, Target = -8.81, Range = 77, Weight = 1.0).

經過第一次最佳化之後的S參數值已經非常接近目標值。如果想要得到更精確的結果，可以選擇不同的最佳化演算法進行多次最佳化。

The image is a graph showing the magnitude of S-Parameters (Scattering Parameters) in decibels (dB) versus frequency in gigahertz (GHz). The graph has a title 'S-Parameters [Magnitude]' and the y-axis is labeled in dB ranging from -60 dB to -5 dB. The x-axis is labeled in GHz ranging from approximately 75.967 GHz to 77.6 GHz. There is a vertical line at 77 GHz. The graph includes six different S-Parameters, each represented by a different color: - S1,1 (red) - S2,1 (green) - S3,1 (blue) - S4,1 (orange) - S5,1 (purple) - S6,1 (cyan) A legend in the center of the graph provides the values of these S-Parameters at 77 GHz: - S1,1: -37.174714 - S2,1: -9.0987518 - S3,1: -6.2500971 - S4,1: -5.8001142 - S5,1: -6.2500971 - S6,1: -9.0987518 The graph is relevant for analyzing the performance of a system in terms of its scattering parameters at different frequencies, which is important in fields such as electrical engineering and telecommunications.

4.檢查相位結果，這裡可以明顯看出S41與其他連接埠的相位差過大。下一期我們將繼續介紹如何透過最佳化的方法來減少相位差。

The image is a graph showing S-Parameters in terms of phase (in degrees) versus frequency (in GHz). The graph has six different traces, each representing a different S-Parameter: S2,1 (green), S3,1 (blue), S4,1 (orange), S5,1 (purple), and S6,1 (brown). The x-axis represents the frequency ranging from approximately 75.967 GHz to 78.086 GHz, and the y-axis represents the phase in degrees ranging from 30 to 165 degrees. There is a vertical line at 77 GHz, highlighting a specific frequency of interest. The legend on the graph provides the phase values at this frequency for each S-Parameter: - S2,1: 39.149104 degrees - S3,1: 52.965086 degrees - S4,1: 150.558 degrees - S5,1: 52.965086 degrees - S6,1: 39.149104 degrees The graph is relevant for analyzing the phase response of different S-Parameters over a specified frequency range, which is important in the design and analysis of RF and microwave circuits.

原文轉載來自: 周明 – CST毫米波雷达仿真解决方案介绍（四）

系列文章：

CST 毫米波雷達模擬（一）
CST毫米波雷達模擬（二）
CST毫米波雷達模擬解決方案介紹（三）

看更多其他文章：

CST電動車EMC模擬（十）——電動車母排（Busbar）電磁及熱模擬
CST毫米波雷達模擬（二）
在CST虛擬雙生上模擬靜電放電

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