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Simulators >> RF Simulators >> modulated s parameter analysis
https://designers-guide.org/forum/YaBB.pl?num=1481888615

Message started by purplewolf on Dec 16^th, 2016, 3:43am

Title: modulated s parameter analysis
Post by purplewolf on Dec 16^th, 2016, 3:43am

Hello,
I was going through a paper of circulator and i found something which catched my attention. For simplicity, I beifly explain. They have designed a circulator and by modulation a varacter with a certain frequency then allow or block the signal passing through different ports in the circulator. The point which i dont get is how they do such a simulation with s-parameter. As far i know, s parameters can never ever incorporate different frequencies like in mixer.. (only harmonic balance or large singal analysis can do it)..Am i missing something..
So they turn on and off the modulation and see the effect on s parameters. In simulation hwo is it possible.. ??i just the paragraphd from their paper briefly.

'''Fig. 7 presents the -paramaters with and without mod-
ulation as obtained through full-wave simulations and the
coupled-mode (17). Simulations were performed by con-
sidering full SPICE models for the varactors and the filter
inductors, while inductors were modeled through a se-
ries combination of inductances and resistances'.

what does it mean?? can someone eleborate the type of s parameters they are referring??

waiting for urgent reply!

Title: Re: modulated s parameter analysis
Post by Andrew Beckett on Dec 29^th, 2016, 10:25am

Wouldn't it be better to give a reference to the full paper? Quoting a section out of context is rather hard to interpret what it means or even what you're asking...

Regards,

Andrew.

Title: Re: modulated s parameter analysis
Post by purplewolf on Jan 14^th, 2017, 11:26am

thanks for reply.

Its based on these related papers of new type of circulators..

Magnetless Microwave Circulators Based on Spatiotemporally Modulated Rings of Coupled Resonators (MTT 11 January 2016)

Magnetic-free non-reciprocity based on staggered commutation (Nature)

Title: Re: modulated s parameter analysis
Post by purplewolf on Jan 15^th, 2017, 12:55am

In summary...The circulator is essentially three LC series circuits connected at a common point. The capacitors of the LC series circuit are modulated by a 120 degrees phase shifted waveforms. This 'magical' modulation makes this three port circuit behave as circulator and I have no clue how to simulate modulated effect using s parameter as shown in paper...

Title: Re: modulated s parameter analysis
Post by Ken Kundert on Jan 18^th, 2017, 1:34am

Any kind of modulated system is a job for SpectreRF. If you want modulated S-parameters, consider using the Periodic S-Parameter (or PSP) analysis.

-Ken

Title: Re: modulated s parameter analysis
Post by purplewolf on Jan 18^th, 2017, 6:06am

Many Thanks Ken. I will share its working for the broader benefit of the community.