CST MWS頻域1D結(jié)果的歸一化問(wèn)題
仿真結(jié)果1Dresults中的時(shí)域信號(hào)都是有幅度信息的,而頻域的結(jié)果(如端口電壓電流等)好多都是歸一化的,也沒(méi)寫(xiě)清楚單位。
相當(dāng)于只有頻率分布,沒(méi)有幅度信息,求教怎么得到完整的頻譜?
不太懂你的意思
電壓電流沒(méi)有進(jìn)行歸一化,只是對(duì)功率進(jìn)行了歸一化
S參數(shù)都是比值,這個(gè)就沒(méi)有歸一化的說(shuō)法了
你想得到什么結(jié)果呢?
比如我做一個(gè)接收天線,看到的接收頻譜就是歸一化的,上面寫(xiě)著nomalized
沒(méi)找到你說(shuō)的歸一化頻譜。我隨便弄了個(gè)天線就得到個(gè)時(shí)域信號(hào)。
截個(gè)圖或者具體說(shuō)說(shuō)叫什么?;蛘吒纱嗌螩ST文件吧
多謝幫助,圖見(jiàn)附件,激勵(lì)天線端口獲得的是S參數(shù)曲線,外部激勵(lì),天線做接收得到歸一化頻譜F
這個(gè)應(yīng)該是平面波激勵(lì)得到的天線端口上的激勵(lì)吧?
這個(gè)相當(dāng)于是端口得到的信號(hào)/激勵(lì)的幅度,本來(lái)就是個(gè)比值
請(qǐng)參考幫助文件中的《Reference Value and Normalizing》一部分:
S-Parameter and F-Parameter calculation
In general, S-Parameter results are given as the ratio of incident and reflected voltage wave spectra at a port, where only one port is excited and all others are perfectly matched. Consequently, for transient simulations, all port signals first have to be transformed into the frequency domain, providing broadband results for one port excitation with only one simulation run.
However, in the case of simultaneous excitation several ports are stimulated at once, so it is not possible to apply the general S-Parameter definition. Now the incident and reflected spectra are given as so-called incident and reflected F-Parameters, all normalized to the spectrum of the reference signal. Furthermore, as an additional result and for a better analysis of the structure's behavior, the reflected spectra of all excited ports are normalized to their own incident spectra, respectively, providing so-called active S-Parameters. Since there might be more energy absorbed at a specific port than it itself has injected, the resulting curves could show active behaviour with values greater than one.
Please note that also in the case of a plane wave or field source excitation, the outgoing signals at ports are used to determine F-Parameters as described above.
謝謝你可是激勵(lì)信號(hào)本來(lái)也是個(gè)寬頻帶的時(shí)域信號(hào),作為基準(zhǔn)的激勵(lì)信號(hào)幅度是指激勵(lì)信號(hào)頻譜的最大值?還是各個(gè)分別對(duì)應(yīng)各個(gè)頻點(diǎn)的幅度
另外請(qǐng)教一下CST中是否自帶傅里葉變換工具
謝謝5l和6l的回答,我是用時(shí)域脈沖平面波照射天線,看端口的耦合電壓,如下圖(第1個(gè)圖)設(shè)置(即加離散端口、不激勵(lì)、選擇監(jiān)測(cè)port的電壓和電流)
1Dresults中port電壓項(xiàng)中:時(shí)域電壓信號(hào)幅度是正常的(第2圖),頻域的形狀對(duì),幅度是不對(duì)的。(不知道CST有沒(méi)有自帶傅里葉變換。)
就是比如我把激勵(lì)信號(hào)放大一千倍,按理說(shuō)這是一個(gè)線性系統(tǒng),那么port的電壓頻譜幅度應(yīng)該hi形狀不變而幅度變大十倍??墒菍?shí)際結(jié)果是頻域幅度和激勵(lì)放大之前是完全一樣的(都是第3個(gè)圖)
先回答你的問(wèn)題,是有傅立葉變換的,在后處理里面
首先load 1D data file,然后再選擇Fourier Transforms
這個(gè)是可以看成一個(gè)線性系統(tǒng),激勵(lì)幅度增加100倍,輸出直接乘以100就好了
這是我隨便找了個(gè)天線仿了下,得到的結(jié)果