[SI-LIST] Re: Prepreg dielectric constant and thickness: what actual values to use?

Guys

This is 200 MHz SSTL.  Correct or incorrect frequency dependent 
dielectric and/or copper surface roughness modeling are insignificant 
when compared to all of the other channel impairments in a poorly 
terminated system at these data rates.  The proper tools for these sorts 
of systems look like hammers and chisels vs.  laser scalpels.

scott


colin_warwick@xxxxxxxxxxx wrote:
> Hi Marc,
>  
>
> Further to Istvan's comment "ideally you need to do the frequency dependent 
> simulation over the entire frequency range of interest," 
> frequency-independent loss violates the Kramers-Kronig relation and is 
> therefore non-causal.
>
>  
>
> Here are a couple of papers about one way of modeling frequency-dependent 
> loss ("Svensson-Djordjevic" model) in such a way that the model is causal:
>
> * C. Svensson and G. Dermer, "Time domain modeling of lossy interconnects," 
> IEEE Trans. Adv. Packaging, vol. 24, no. 2, pp. 191-196, May 2001.
>
> * T. Arabi, A. Murphy, T. Sarkar, R. Harrington, and A. Djordjevic, "On the 
> modeling of conductor and substrate losses in multiconductor, multidielectric 
> transmission line systems," IEEE Trans. Microwave Theory Tech., vol. 39, no. 
> 7, pp.1090-1097, Jul. 1991.
>
>  
>
> Also, if you happen to be going to IEEE MMT-S IMS 2009 in Boston in June, you 
> can check out our paper about Svensson-Djordjevic implementation:
>
> * Radoslaw M. Biernacki, Yunhui Chu, Fangyi Rao, and Yutao Hu "Causality 
> Enforcement in Fast EM-based Simulation of Multilayer Transmission Lines" 
>
>  
>
> hth
>
> -- Colin Warwick, Agilent EEsof EDA
>
> http://signal-integrity-tips.com
>
>  
>
>  
>
> -----Original Message-----
>
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On 
> Behalf Of Marc Battyani
>
> Sent: Thursday, May 21, 2009 9:13 AM
>
> To: si-list
>
> Subject: [SI-LIST] Prepreg dielectric constant and thickness: what actual 
> values to use?
>
>  
>
>  
>
>  Hi,
>
> When you specify a stackup the thicknesses of the cores are well defined but
>
> the for the prepreg layers it's less obvious. So when using one or several
>
> prepreg sheets do you just use and add the basic thicknesses or is there a
>
> correction to make?
>
>  
>
> For the dielectric constant of those materials, when you have 4.3-4.5 @ 1MHz
>
> and 3.8-4.0 @ 1GHz what value should we use as a basis for the simulations
>
> for 125MHz HSTL or 200MHz SSTL for instance?
>
>  
>
> Thanks,
>
>  
>
> Marc
>
>
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