Dear Yang, [quote userid="461342" url="~/cadence_technology_forums/f/rf-design/47813/problem-of-nport-pss-shooting-simulation/1376220#1376220"] In summary, if I choose PSS_shooting, my coupler doesn't work. But if I choose PSS_HB, my LO doesn't work. I wonder if there is a way to get out of this dilemma. [/quote] I am not Andrew and am not suggesting my response will be as good or thorough as he might provide! However, a couple of thoughts came to mind when I read your recent forum post that I thought I might pass by you. 1. [quote userid="461342" url="~/cadence_technology_forums/f/rf-design/47813/problem-of-nport-pss-shooting-simulation/1376220#1376220"] case 1. SP+AC case 2. PSS(HB)+PAC+PSP case 3. PSS(shooting)+PAC+PSP The results of case 1 and case 2 is identical to what I got from ADS. However, the result of case 3 is quite different. [/quote] a. Did you ever include what the symptom of your case 3? In other words, how is the solution in case 3 different than that in cases 1 and 2? For me anyway, this would help understand possible issues. b. It would be helpful to also provide the simulation settings (input.scs files) and simulator outputs (spectre.out files) for each of the 3 cases. 2. Without specific knowledge concerning your EMX S-parameter network, I have no idea if it is a passive or contains active devices. As such, there are different techniques used to handle S-parameter files and these can have a first-order effect on the solution. I did inspect your S-parameter file and it does contain a DC term - which is good. Since I don't know its details nor the specifics of your simulation settings, I can only recommend you review the On-line support article at URL: if you have not already seen this. It has a number of suggestions regarding the use of HB and Shooting algorithms and their use in pss simulations that may provide you some insights since you are aware of the specific simulator settings. https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1Od0000007MVjAEAW&pageName=ArticleContent With regard to your use of the S-parameter file, Tawna Wilsey has prepared an excellent document detailing different items to study regarding your simulator settings and actual S-parameter file at the On-line support URL: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O3w000009bgt4EAA&pageName=ArticleContent&oMenu=People%20who%20viewed%20this%20also%20viewed 3. [quote userid="461342" url="~/cadence_technology_forums/f/rf-design/47813/problem-of-nport-pss-shooting-simulation/1376220#1376220"]However, in my system, there is also LO generation circuit (including RO). I found that PSS(HB) doesn't work when LO generation circuit is included.[/quote] a. Is the LO intended to be the same frequency as the RO (ring oscillator)? b. Do you have dividers between the RO output and the LO frequency? c. If the two frequencies are not the same and asynchronous, are you sure the solution is actually periodic? Shawn
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