• 易迪拓培训,专注于微波、射频、天线设计工程师的培养
  • 1
  • 2
  • 3
  • 4
首页 > ADS > ADS FAQ > Why TDR impedance varies for my Transmission line and corresponding s-parameter file

Why TDR impedance varies for my Transmission line and corresponding s-parameter file

录入:edatop.com    点击:

Hi,

I have created a differential channel with microstrip transmission line with CILD. I have also extracted the s-parameter file (.s4p) file for the corresponding transmission line. I actually will need this .s4p file to use in cadence. I was checking the TDR impedance of the transmission line and the of the extracted s-parameter file of my transmission line. Somehow it doesn't match in the beginning.

My s-aparameter touchstone file format generated in ADS using conventional method of 4 port of 50 ohm each.

闂傚倸鍊搁崐鎼佸磹閹间礁纾瑰瀣捣閻棗銆掑锝呬壕濡ょ姷鍋涢ˇ鐢稿垂妤e啫绠涘ù锝呮贡缁嬩胶绱撻崒姘偓鐑芥倿閿曚焦鎳岄梻浣告啞閻熴儳鎹㈠鈧濠氭偄绾拌鲸鏅梺鎸庣箓濞诧絽效濡ゅ懏鍋℃繝濠傛噹椤eジ鎮介娑樻诞闁诡喗鐟︾换婵嬪炊閵娧冨妇濠电姷鏁搁崐顖炲焵椤掑嫬纾婚柟鍓х帛閻撴盯鎮楅敐搴′簽濠⒀冪仛閹便劍绻濋崨顕呬哗闂佸湱鎳撶€氱増淇婇幖浣肝ㄩ柨鏃€鍎崇紞鎺楁⒒閸屾瑨鍏岄柟铏崌瀹曠敻寮介鐐殿唵闂佽法鍣﹂幏锟�...

My test bench to compare the TDR impedance varies for my Transmission line and corresponding s-parameter file:

闂傚倸鍊搁崐鎼佸磹閹间礁纾瑰瀣捣閻棗銆掑锝呬壕濡ょ姷鍋涢ˇ鐢稿垂妤e啫绠涘ù锝呮贡缁嬩胶绱撻崒姘偓鐑芥倿閿曚焦鎳岄梻浣告啞閻熴儳鎹㈠鈧濠氭偄绾拌鲸鏅梺鎸庣箓濞诧絽效濡ゅ懏鍋℃繝濠傛噹椤eジ鎮介娑樻诞闁诡喗鐟︾换婵嬪炊閵娧冨妇濠电姷鏁搁崐顖炲焵椤掑嫬纾婚柟鍓х帛閻撴盯鎮楅敐搴′簽濠⒀冪仛閹便劍绻濋崨顕呬哗闂佸湱鎳撶€氱増淇婇幖浣肝ㄩ柨鏃€鍎崇紞鎺楁⒒閸屾瑨鍏岄柟铏崌瀹曠敻寮介鐐殿唵闂佽法鍣﹂幏锟�...

S-parameter port mapping:

闂傚倸鍊搁崐鎼佸磹閹间礁纾瑰瀣捣閻棗銆掑锝呬壕濡ょ姷鍋涢ˇ鐢稿垂妤e啫绠涘ù锝呮贡缁嬩胶绱撻崒姘偓鐑芥倿閿曚焦鎳岄梻浣告啞閻熴儳鎹㈠鈧濠氭偄绾拌鲸鏅梺鎸庣箓濞诧絽效濡ゅ懏鍋℃繝濠傛噹椤eジ鎮介娑樻诞闁诡喗鐟︾换婵嬪炊閵娧冨妇濠电姷鏁搁崐顖炲焵椤掑嫬纾婚柟鍓х帛閻撴盯鎮楅敐搴′簽濠⒀冪仛閹便劍绻濋崨顕呬哗闂佸湱鎳撶€氱増淇婇幖浣肝ㄩ柨鏃€鍎崇紞鎺楁⒒閸屾瑨鍏岄柟铏崌瀹曠敻寮介鐐殿唵闂佽法鍣﹂幏锟�...

The resulting TDR impedance plot of both:

闂傚倸鍊搁崐鎼佸磹閹间礁纾瑰瀣捣閻棗銆掑锝呬壕濡ょ姷鍋涢ˇ鐢稿垂妤e啫绠涘ù锝呮贡缁嬩胶绱撻崒姘偓鐑芥倿閿曚焦鎳岄梻浣告啞閻熴儳鎹㈠鈧濠氭偄绾拌鲸鏅梺鎸庣箓濞诧絽效濡ゅ懏鍋℃繝濠傛噹椤eジ鎮介娑樻诞闁诡喗鐟︾换婵嬪炊閵娧冨妇濠电姷鏁搁崐顖炲焵椤掑嫬纾婚柟鍓х帛閻撴盯鎮楅敐搴′簽濠⒀冪仛閹便劍绻濋崨顕呬哗闂佸湱鎳撶€氱増淇婇幖浣肝ㄩ柨鏃€鍎崇紞鎺楁⒒閸屾瑨鍏岄柟铏崌瀹曠敻寮介鐐殿唵闂佽法鍣﹂幏锟�...

You can see, till 4ns, the impedance is not same, but I used the same equation to get the impedance. Can anyone help me to know why did this happened and what to do to fix it?

申明:网友回复良莠不齐,仅供参考。如需专业帮助,请学习易迪拓培训专家讲授的ADS视频培训课程

上一篇:MOM and Schematic not matching
下一篇:Extract S-parameter from Cadence allegro file

ADS培训课程推荐详情>>

  网站地图