Shaohua: I suppose you did a wrong connection in netlist and a wrong unit in TL length. Try below deck: ***************************** L1 in1 out1 20nH T1 out1 GND out2 GND Z0=100 TD=5n L=1 P1 out2 GND port=1 Zo=50 ac=1v dc=0 P2 out1 GND port=2 Zo=50 ac=1v dc=0 * ******** Analysis .LIN filename=ideal_TL_output format=touchstone dataformat=db .AC DEC 401 1e6 20e9 .OPTION POST $ Also print analysis results in the post-processor data * ********* output .PROBE AC S11(dB) s12(dB) .PRINT AC S11(dB) $ print the results in the output listing file .END ************************* Benny Yan IO Methodology Inc. -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Shaohua Li Sent: Friday, July 13, 2007 4:48 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] A Hspice question Hi all, I am new in studying HSpice and get stuck in a small test program. I know there are a lot of experts here, so I seek help from you. Here is my problem. A section of 100 Ohm transmission line is connected to 50 Ohm VNA through an 20 nH inductor. The TL is 1 m long and delay is 5 ns/meter, which means phase velocity 2e8 m/s. The length of the TL is long enough to see oscillation on S parameter, however, the plots of S11 and S12 in dB are smooth. I don't know what is wrong. Could you please give me some idea? * transmission line test L1 in1 out1 20nH T1 in1 GND out2 GND Z0=100 TD=5n L=1m P1 out2 GND port=1 Zo=50 ac=1v dc=0 P2 out1 GND port=2 Zo=50 ac=1v dc=0 * ******** Analysis .LIN filename=ideal_TL_output format=touchstone dataformat=mp .AC DEC 401 1e6 20e9 .OPTION POST $ Also print analysis results in the post-processor data * ********* output .PROBE AC S11(dB) s12(dB) .PRINT AC S11(dB) $ print the results in the output listing file .END ***** Your help is sincerely appreciated. Shaohua --------------------------------- Finding fabulous fares is fun. Let Yahoo! FareChase search your favorite travel sites to find flight and hotel bargains. ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu