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2020年12月20日 星期日

Keysight ADS 微波整流器(Rectifier) 常用公式

微波整流器(Rectifier) 常用公式 

微波整流器(RF/Microwave Rectifier)這傢伙也是大訊號, 所以很多公式都得自己來, 因為自己常用到, 所以在這邊做個筆記, 希望對大家有幫助, 圖片稍微細節請參考英文版 [ link ]

1. 使用 Harmonic Balance 模擬, 到Source-Freq Domain拿 P_1tone當來源, 我習慣把輸入頻率跟輸入功率都設為變數"var". 

2. 把輸入的地方節點命名為 vin, 順便串聯上電流表, 把直流輸出的節點命名為vout

3. (有想到再補)


計算整流器效率 (efficiency)

Poutdc=mag(vout[::,0])**2/RL
eff=100*Poutdc/dbmtow(mpin)


大訊號輸入阻抗

zind=vin[1]/I_in.i[1]

轉成反射係數, 就可以畫成 Smith chart 拉

Gamma=(zind-50)/(zind+50)

當然也可以轉換成 dB 

s11indb=20*log10(abs(Gamma))






祝大家設計整流器順利, 有什麼想知道的或者新穎的玩法, 也歡迎跟我討論

[Keysight ADS] Some equations for RF/microwave rectifier design

been designing RF rectifiers for years. Since I myself use these equations quite often, I write them down here and hope this page would help you to speed up. 

Note that rectifiers are large-signal operation meaning "Harmonic Balance" simulation is mostly used.
Firstly, you have to have "harmonic balance" and secondly, you have to set a node at the output of the rectifier as e.g. vout. 
To obtain input impedance, you have to add a note at the input port as e.g. vin as well as a current meter.
We need to calculate input impedance from the impedance definition.

Anyway, seeing figures below are easier than texts. 

Figure of the input part

Figure of the output part



The MeasEqu I set


Anyway, you can copy these equations below and paste into your schematic using MeasEqu as I did or use EQU function in ADS display.




To calculate efficiency:

Poutdc=mag(vout[::,0])**2/RL
eff=100*Poutdc/dbmtow(mpin)


To calculate large-signal input impedance:

zind=vin[1]/I_in.i[1]

You can convert the impedance to Gamma and then plot in Smith chart as:
Gamma=(zind-50)/(zind+50)

Of course, you can plot in dB:

s11indb=20*log10(abs(Gamma))






Have fun of rectifier design. 


2019年11月17日 星期日

[Keysight ADS tips] Calculate characteristic impedance (Z0) and propagation constant, (Gamma)

* to calculate characteristic impedance, Z0, of a transmission line :

simply copy and paste the following equations into ADS Data Display
abcd=stoabcd(S)
z0=sqrt(abcd(1,2)/abcd(2,1))
Of course, you have to run S-parameter simulation in ADS schematic

* To calculate propagation constant (Gamma) of a transmission line

Gamma=acosh(abcd(1,1)/(TLleng))
where TLleng is the length of the line.
Once Gamma is obtained, attenuation constant can be known as well. remember to convert the unit into dB.


//
Schematic is shown below. I here use ideal transmission line as an example. Of course we can replace it to a microstrip line or any s2p files such as EM simulation results.



Copy and paste the equations in Data display window:





Have fun with ADS


* for TEM mode only, lossless transmission line assumed




--reference
Pozar textbook

Wiki : Characteristic impedance,

2019年11月16日 星期六

[Keysight ADS] 求傳輸線特性阻抗Z0 與傳播係數 Gamma

[Keysight ADS tips: calculate characteristic impedance (Z0) and propagation constant, (Gamma) in english here]

使用 ADS 應該超過十年了吧, 累積了一些"奇奇怪怪"的心得跟攻略, 有空就記錄一點, 對自己也有幫助, 如果要使用的時候不用每次都在去翻一次之前怎麼做的.
這篇適合稍有一點基礎的使用者

* 計算傳輸線特性阻抗(z0), 把以下的公式複製貼上ADS的 Data Display 或者用Meas打在 Schmatic內皆可

abcd=stoabcd(S)
z0=sqrt(abcd(1,2)/abcd(2,1))

* 計算傳輸線的傳播係數Propagation constant (Gamma)

Gamma=acosh(abcd(1,1)/(TLleng))
ps. TLleng為傳輸線的長度, 一但有了Gamma再求衰減係數就簡單啦, 注意單位要轉換成dB就是





電路圖如下, 這個例子是使用ideal的傳輸線, 當然你可以放入真正的microstrip line, 或者EM的s2p檔也可以的



然後在顯示的視窗複製貼上公式, 就可以得到拉



備註:TEM傳播限定, 假設傳輸線是無損失的 lossless
-- 參考資料
Pozar textbook
Wiki : 特性阻抗, ABCD矩陣, 傳播常數




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