Please refer to Stripline Differential Pair step1, but select [Modeler Units] as "in" (inches) and [Solution Type] as [Driven Modal].
2.1 先把裡面空心部分的喇叭狀waveguide畫出,外面再畫一個材質金屬的圓柱,兩者相減即得一個waveguide horn,外面再畫一個距離l/4的圓柱設為radiation boundary,過程中只需用到以下四個指令[Draw] [Cylinder][Draw] [Cone][Modeler] [Boolean] [Subtract][HFSS] [Boundaries] [Assign] [Radiation]
2.2 Create the wave port sheet[Draw] [Circle]
2.3 Assign wave portselect "p1" sheet, then [HFSS] [Excitations] [Assign] [Wave Port]assign port name "p1", then set [Number of Modes] as "2" (兩個正交激勵模態,可以形成圓極化場)
In general case, choose [Set mode polarity using integration lines]. (不需要align E-field)如果一個wave port有degenerate mode(多模態組合),那就需要以下的mode alignment (通常waveguide才會用到)並非所有的wave port都需要設積分線, 只有需要mode alignment的情況, wave port才需積分線 。讀者可以自行嘗試,在此步驟中,不要設積分線,一樣跑得出結果,只是你的場不會像本文step4.4, 4.5會旋轉。
3.1 Create Radiation Setup[HFSS] [Radiation] [Insert Far Field Setup] [Infinite Sphere]
3.2 Create Analysis Setup[HFSS] [Analysis Setup] [Add Solution Setup]
3.3 Run AnalysisHFSS Validation CheckHFSS Analyze All
4.1 Edit SourcesHFSS Fields Edit Sources
4.2 Plot 2D Radiation PatternHFSS Results Create Far Fields Report Radiation Pattern
4.3 Plot 3D Far Field RadiationHFSS Results Create Far Fields Report 3D Polar Plot
4.4 讓3D model與3D radiation plot together (場結合後的位置是錯的, 詳見問題與討論5.3)
4.5 Plot E-field(右旋圓極化)
4.6 Plot E-field(左旋圓極化)
4.7 All Antenna Parameters
5.1 何謂圓極化 (circular polarization)Ans:大小相等,相位差90度的兩個正交電場,會形成一個圓極化天線,此例是一典型的線極化轉圓極化的轉換器5.2 在step2.3中,Alignment Groups設兩個或一個,為什麼看起來沒差?Ans:只有選了[,才會出現[Alignment Groups]欄位。help的解釋是說:確保同一個group內的mode在積分線上非零電壓,還是看不懂是什東東5.3 為何step4.4的3D far field不是從wave port開始打出能量,而是從wave guide的出口處才有field?Ans:其實step4.4打出的場圖相對位置是有問題的,因為far field radiation setup內的座標選定沒設對