FreeLists / si-list / [SI-LIST] Re: Loss tangent and Dielectric conductance

[Steve Corey <steve@xxxxxxxxxxxxxx>]

> Gd=2*pi*f *tand*C (capacitance)
> C=Er*Co
> Co= Eo A/d

Just a point of interest and warning regarding the above equations -- it is
often overlooked that the real and imaginary parts of epsilon are not
independent of one another.  This fact was first published in 1926 I believe,
and comes as a direct result of applying conservation of energy constraints to
Maxwell's equations.  It turns out that if tand is constant, it must be zero.
This is the lossless case, and as many on this list are aware, this special
case is running out of gas for digital design.  Another result is that if G
varies with frequency, C must also vary with frequency.  (The same is true for
L and R.)  The above equations support this behavior, as long as it is
understood that

1.  tand is either frequency-varying or zero
2.  Er and tand are not independent of one another, but are related by the
so-called Kramers-Kronig relation

  -- Steve

 -------------------------------------------
 Steven D. Corey, Ph.D.
 Time Domain Analysis Systems, Inc.
 "The Interconnect Modeling Company."
 http://www.tdasystems.com

 email: steve@xxxxxxxxxxxxxx
 phone: (503) 246-2272
 fax:   (503) 246-2282
 -------------------------------------------

Ozgur Misman wrote:

> Actually formula do exist,
> I must have missed the capacitance in tmy previous E-mail
> let me rewrite it as
> Gd=2*pi*f *tand*C (capacitance)
> C=Er*Co
> Co= Eo A/d
>
> Mick is right in saying that the dielectric loss is a property of the
> material and conductance depends on the circuit as well. That link is in
> the capacitance term.
> The formula is derived assuming a resistance in parallel with
> capaciatance.and conductance is defined as 1/resistance.
> Hope this clarifies
>
> Ozgur Misman
> ---------------------- Forwarded by Ozgur Misman/CHAZ/AAWW on 11/01/2001
> 09:34 AM ---------------------------
>
> 11/01/2001 08:51 AM
> Ozgur Misman - Chandler - 5080
> Sr Engineer
> 01 We've Just Begun
>
> To:   plaflamm@xxxxxxxx
> cc:   si-list@xxxxxxxxxxxxx
>
> Subject:  Re: [SI-LIST] Loss tangent and Dielectric conductance  (Document
>       link: Ozgur Misman)
>
> Hi Peter,
> I think the for mula is :   Gd (conductance)=2*pi*frequency*tand(loss
> tangent)* Eo (permittivity of the free space;8.854e-12f/m)* dielectric
> constant;Er
> Ozgur Misman
> Amkor Technology
>
> Peter LaFlamme <plaflamm@xxxxxxxx>@freelists.org on 11/01/2001 06:45:13 AM
>
> Please respond to plaflamm@xxxxxxxx
>
> Sent by:  si-list-bounce@xxxxxxxxxxxxx
>
> To:   si-list <si-list@xxxxxxxxxxxxx>
> cc:
>
> Subject:  [SI-LIST] Loss tangent and Dielectric conductance
>
> Hi SI Folks,
> I would like to know the relationship between Loss Tangent and Dielectric
> loss. In other words, If I know the "loss tangent" at a given frequency for
> a particular dielectric what is the formula to convert this into the
> Dielectric conductance(Gd) ?
>
> Thanks,
> Peter
>
> --
> Peter LaFlamme
>
> Applied Micro Circuits Corp.
> Staff System Applications Engineer
> 200 Minuteman Rd, 3rd Floor
> Andover, MA 01810
>
> 978-247-8470 phone
> 978-623-0055 Fax
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