Re: [SI-LIST] : Upper limit of interplane capacitance

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From: Erik Daniel ([email protected])
Date: Fri Jun 16 2000 - 07:47:09 PDT


George-

Thermal vibrations and associated radiation are certainly responsible
for the *dissipation* of the absorbed energy, but the *absorbtion*
processes that dictate the loss tangent are based on electronic state
excitations.

                                        - Erik

[email protected] wrote:
>
> Erik,
>
> I agree with you in most parts. But I believe thermal energy produces
> radiation in the infrared
> spectrum. The microwave excites electron resonance (or vibrational modes),
> and infrared
> light is radiated. Thermal/heat does account for part of the dielectric
> loss.
>
> Just my $0.02
>
> George
>
> -----Original Message-----
> From: Daniel, Erik S. [mailto:[email protected]]
> Sent: Thursday, June 15, 2000 9:37 AM
> To: [email protected]
> Subject: RE: [SI-LIST] : Upper limit of interplane capacitance
>
> Larry-
>
> I believe the absorbtion resonances are typically vibrational modes of the
> molecules withing the dielectric medium which tend to be in the far
> infrared, extending towards microwave frequencies. Typical frequencies
> refered to on this list (e.g. a couple GHz) are still a ways down from the
> center frequency of the resonances, but the "tails" of these resonances are
> typically responsible for the rise of dielectric loss with frequency. The
> resonances are definitely still quantum mechanical in nature, describing
> quantized electronic states, and "photons" (quanta of E/M energy) are still
> absorbed. I don't believe thermal/acoustic losses (i.e. phonon resonances)
> are typically involved.
>
> - Erik
>
> > -----Original Message-----
> > From: Larry Smith [mailto:[email protected]]
> > Sent: Thursday, June 15, 2000 10:47 AM
> > To: [email protected]; [email protected]
> > Subject: RE: [SI-LIST] : Upper limit of interplane capacitance
> >
> >
> > Greg - it is a bit of a stretch, but if I go back to my Quantum
> > Mechanics from years ago, I think the dielectric loss is more of
> > a sonic phenenon than a photo electric effect. With the photo
> > electric effect, a packet of energy is obsorbed that is exactly
> > right to lift an electron from one energy state to another. When
> > the electron falls back it emits a photon.
> >
> > With dielectric loss, molecules physicaly vibrate more like a
> > sound wave. The losses show up as thermal rather than electromagnetic
> > energy. But you are correct, dielectric loss is a material property.
> >
> > I'm sure somebody will tell me if this is completely off base...
> >
> > regards,
> > Larry Smith
> > Sun Microsystems
> >
> > > From: [email protected]
> > > X-Lotus-FromDomain: IBMUS
> > > To: [email protected]
> > > Date: Thu, 15 Jun 2000 09:23:26 -0500
> > > Subject: RE: [SI-LIST] : Upper limit of interplane capacitance
> > > Mime-Version: 1.0
> > > Content-Disposition: inline
> > >
> > > Larry and Erik,
> > >
> > > [Erik Daniel wrote]
> > > > I agree with most of your comments on power plane
> > capacitance, but I have
> > > to
> > > > disagree with one point -- dielectric loss does NOT decrease with
> > > decreased
> > > > thickness of the dielectric -- dielectric loss is
> > independent of the
> > > > dielectric thickness in particular, and all geometrical
> > concerns in
> > > general
> > > > (unlike skin-effect loss).
> > >
> > > Someone once explained dielectric loss to me as absorption
> > of the energy
> > > in the E/M field by quantum resonances in the molecules
> > that make up the
> > > dielectric material. In my mind, I thought this sounded
> > analogous to the
> > > photoelectric effect, where you shine light of a particular
> > frequency on
> > > an atom and it gets absorbed if the frequency corresponds
> > to one of its
> > > quantum states. Is this truly the physical origin of
> > dielectric loss?
> > > If so, that would explain why it's strictly a material
> > property and not
> > > geometry-dependent...
> > >
> > > Greg Edlund
> > > Advisory Engineer, Critical Net Analysis
> > > IBM
> > > 3605 Hwy. 52 N, Dept. HDC
> > > Rochester, MN 55901
> > > [email protected]
> > >
> > >
> > >
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-- 
==================================================================
Erik Daniel, Ph.D.                         Mayo Foundation
Voice:  (507) 284-1634                     Guggenheim 1011B
Fax:    (507) 284-9171                     200 First Street SW
E-mail: [email protected]               Rochester, MN  55905 
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