Relative Permitivity / Dielectric constant at 300 GHz /THz Freq?

@ 300 GHz or 0.3 THz, Can someone let me know the the relative permitivity/Dielectric constant, Loss Tangent and thickness of following substrates;

1. Silicon Dioxide
2. Silicon

Awaiting replies.
Regards

http://physics.info/dielectrics/
http://en.m.wikipedia.org/wiki/Relative_permittivity
Impurities will affect results and loss tangent. Generally permittivity ε degrades slowly when loss tangent starts rising but more complex molecular behaviours begin as well with "complex" values.

You need to contact a supplier for details.

Permittivities of various materials are sometimes published in manuals, but at the THz range, not many data are established. Search for recent university theses or use your laboratory to determine what you need.

Ok..Ill look for something..