make a nice-looking figure in Matlab for IEEE papers

 make a nice-looking figure in Matlab for IEEE papers

I constantly am asked how to make a good, nice-looking figure in Matlab for IEEE papers. I have my personal taste and own receipt. It looks quite decent from my point of view. FYI. if you have another taste, feel free to share with me.

Here is the receipt:

• Import your data of course, e.g. variables x and y
• create a new figure
• fig=figure(1) 
• Key point is that DO NOT modify the window size. 
• Keep the size as default
• Plot data
• plot(x,y,'b-','LineWidth',2)
• Use Linewidth to be 2
• Linestyle is up to you
• Export the figure in EPS format which is fully supported by LaTeX
• you can use "save as.." in the menu of the figure 
• or use command saveas(fig,'fig.eps')

Simple as that.  

Enjoy plotting figures.

微波整流器(RF/mircowave rectifier)心得分享- 入門篇

小弟做了幾年的微波整流器(RF/microwave rectifier), 一點小心得整理跟大家分享, 這邊提到的都是離散的設計, MMIC是另外一回事.

微波整流器的基本原理很簡單, 就是使用元件的非線性特性, 取出產生的直流項來用, 並且把二階或更高頻的諧給壓抑, 原理很簡單, 此電路最主要就是在追求高效率,後來當然也有寬頻的, 雙頻的, 多頻的有的沒有的變化.

整流器的效率定義也很直覺, 就是輸出的直流功率放分子, 輸入的交流(微波)功率方分母, 物理意義也很容易理解. eff= PDCout / PACin

至於效率跟什麼相關? 基本上取決於元件本身的寄生電阻, 寄生電容, 電路的輸入匹配, 負載電阻, PCB板材本身的消耗, 例如微帶線(microstrip line)的損失... 等等... 但最主要最主要還是取決於使用的非線性元件.

非線性元件大致上可分為使用1.二極體(diode)跟2.電晶體(transistor)的.

依照匹被電路常用的又可分為 class E, class F, class F-1, harmonic-tuned, 等等, 或者就不管諧波, 直接匹配的也是可以. 

因為整流器是高度非線性的電路, 所以模擬的時候大多採用 harmonic-balance, 包括看輸入阻抗也是, 小弟之前有 review 一些微波整流器的論文, 然後用s-parameter看輸入阻抗, 我都不明白這樣看怎麼會對?! 因為大多數時候並不在小訊號操作阿.

有些論文小弟自己覺得不錯, 供各位參考, 這篇蠻適合入門的 這篇也不錯 或者各位可以搜尋下面幾位學者的論文, 應該都蠻有參考價值的, e.g. Prof.  Zoya Popovic, Prof. Ke Wu [1], 若干中國學者這個領域也都做得不錯.

Tips

1. 有人使用調變訊號增加效率, A. Georgiadis [link] 做很多類似的, 但我不確定是不是他們第一個提出的
2. Bandstop是我最近很欣賞的設計, [link]
3. 當然高動態範圍也是大家追求的目標之一 [link]
4. (待增加)

小弟整理了一些模擬常用的公式在這邊 [link], 有興趣的人請自行移動, 這篇文章是比較屬於入門類型的, 希望對剛進入這個領域的,或想進入這個領域的人有少許幫助.

有空再慢慢補上這篇, 如果有什麼想要跟小弟討論的也歡迎留言討論 

[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.