Re: RF Conductivity of thin Mo film

Peter Simon wrote:
> "Uncle Al" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
>
> > Peter Simon wrote:
> >
> > > I am very interested in predicting the RF reflection and transmission
> > > (at a frequency of 2.6 GHz) through a thin layer of Molybdenum (Mo)
> > > that may be sputtered onto a 2 mil plastic substrate.
>  [snip]
>
> > Are you interested in the amount of Mo deposited and then RF
> > properties, or something else?  Why not have a naked quartz oscillator
> > crystal in there and track the change of resonant frequency with
> > increasing mass?  It's a commercial system.  Do your RF measurements
> > concurrently, already knowing the film thickness to excellent accuracy
>
> [snip]
>
> > The only no-no is that quartz undergoes a solid state twinning
> > transition at 573 C.  Don't go above 500 C at the crystal.
> >
> > --
> > Uncle Al
>
>
> I don't wish to measure the amount of Mo deposited.  I am attempting to
> predict the amount of RF performance degradation to expect over the life of
> a spacecraft mission due to undesired Mo sputtering.  My calculations will
> help to determine the maximum tolerable Mo layer thickness, and will be used
> as inputs into the decision as to what, if anything, needs to be done about
> the undesired sputtering.

  The plastic substrate is an RF window and you're 
concerned with attenuation? Provide a cold finger between 
the source and the window.

  What's the actual exercise? What restrictions do you have?

  Mark L. Fergerson