The relative permeability of most materials that do not
contain any ferromagnetic atoms is very close to 1.0,
and the RF permeability is generally less than the DC value
for most materials. All of the materials you mentioned are
non-magnetic so the permeability will be about the same
and very close to 1.0 relative.
You say this is for *RF* MEMS; you will find with many
materials that the properties of Permittivity, Permeability,
and Conductivity vary with frequency, as well as with the
particular microstructure of the material.
Therefore values of those parameters specified at a
given frequency may not be as accurate as necessary at
a different frequency of interest. Often one can find the
values for DC, low frequencies in the 10-100kHz or 1MHz
range, then perhaps values taken at 1GHz and perhaps at
optical frequencies.
You may have to interpolate various data tables to estimate
the values at your particular frequencies.
Also for RF frqeuencies especially those in excess of
several hundred MHz, you'll find that parameters such
as the following can effect the conductivity and permittivity
-- the material's crystal / grain structure, porosity, purity,
surface roughness, substrate or overcoat layer effects, et.
al.
Aluminium, speficically, comes in many alloys and those
influence its nanostructure and microwave conductivity
somewhat, though in general the materials used for
high speed IC foundty applications may be expected to
yield relatively smooth metallized layers with relatively
good conductivity. Check various four-point-probe
measurements of various thicknesses of wafer
Aluminization layers for resistivity information beyond
what is available in the tables below if that's relevant to you.
Check the following sources for some parameters:
http://www.memsnet.org/material/
http://webelements.com/
The "CRC Handbook of Chemistry and Physics".
et. al.