*From*: "Grossman, Brett" <brett.grossman@xxxxxxxxx>*To*: "Moeller, Merrick" <mmoeller@xxxxxxxxxxxxxxx>, "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>*Date*: Tue, 10 Nov 2009 15:07:32 -0800

Merrick, I've run into this situation bunches of times, and I will say that your success may depend on how many assumptions you are able to make. Consider that if the data you have is a 2-port s-parameter matrix, you have essentially 4 knowns (S11, S12, S21, S22). If you wish to split it into two 2-port matrices (a & b), with no assumptions, this is 8 unknowns (S11a, S12a, ..., S11b, S12b,...). So with no assumptions, you can see the problem will be difficult to solve (8 unknowns vs. 4 knowns). However, it may not be unrealistic to say that the two s-parameter matrices are equivalent (i.e. you split your passive device in half and each half is the same). In which case one matrix becomes the transpose of the other, such that: S11a = S22b S12a = S21b ... By using these assumptions and simplifying the problem in this way, it is possible you could arrive at a solution in theory. In practice I've found a few of the assumptions I'd need to make, I simply can't accept. Also keep in mind that strictly speaking you can't cascade s-parameters, and would need to convert them into t-parameters to solve the problem (and likely back to s-parameters for your application). In the case you are dealing with > 2-ports, the translation to t-parameters can be ambiguous. Check out the following: J. Frei, X.-D. Cai, and S. Muller, Multiport S-parameter and T-parameter Conversion with Symmetry Extension, IEEE Trans. On Microwave Theory and Tech., Nov. 2008, pp2493 for a reference. There is also a reference (though I do not have a citation), which address this problem with a software tool that I believe you can purchase. You may look up a company called Ultimetrix or google the name Vahe Adamian for the approach they have developed for splitting a fixture into 2-halves. Best regards, -Brett -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Moeller, Merrick Sent: Tuesday, November 10, 2009 10:04 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] S-parameter Bisection Is it possible to split a passive S-parameter matrix into two equal sections? For example; given s-parameters for a transmission line of a 10" length can the matrix be split into two 5" lengths. Assume that the passive s-parameter obeys reciprocity. The reason I'm asking is that I have a test fixture on each end of my measurement that I'm trying to de-embed. The insertion loss can be subtracted very easily, but the return loss and other parameters have a great deal of error dealing with de-embedding from one side of the DUT only. I'm hoping to break the fixture into two equal parts without having a direct point of measurement to do so otherwise. Merrick M. Moeller The information contained in this electronic mail message is privileged and confidential information, may be subject to the attorney-client privilege and is intended solely for the use of the addressee. If you are not the intended recipient, any disclosure, copying, distribution, or the taking of any action in reliance on the contents of this message is strictly prohibited. If you have received this message in error, please notify me immediately. ------------------------------------------------------------------ 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 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 Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu

**Follow-Ups**:**[SI-LIST] Re: S-parameter Bisection***From:*Luciano Boglione

**References**:**[SI-LIST] S-parameter Bisection***From:*Moeller, Merrick

- » [SI-LIST] S-parameter Bisection- Moeller, Merrick
- » [SI-LIST] Re: S-parameter Bisection- wolfgang . maichen
- » [SI-LIST] Re: S-parameter Bisection- steve weir
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- » [SI-LIST] Re: S-parameter Bisection- Zabinski, Patrick
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