If use the example above, by relative permittivity and loss tangent, one can get the imaginary part of the dielectric constant,
once know the permittivity, the refractive index can be easily caculated, and if the material is not a gain media, then imaginary part for the refractive index is always positive. you can double check the data with the penetration depth. see:
E=E0*e^(-z/(2*l)), where l is the penetration depth. you will get the E field for depth z if you know the incidence E field(E0). For E field on other direciton, your information is not enough.
Specific absorption rate (SAR) in your question is most likely to be one average value( otherwise it has to be a funtion of a lot of paramters, such as position, organ et.al).Generally it's a volum integration,see:
If we assume the issue is not magnetic , to simplify
at depth z,
Total absorbed energy would be the integration for above with depth.
You have to know another parameter(the thickness of the sample,h) to do the integration, finally:
The total energy=conductivityE0^2(hl)(1-e^(h/l))
And the total power is the time average for the total energy,if E0 is a sine wave of time,then total power would be the half of above.
And you also need to know the total mass(M) for your sample, now:
SAR=the total power/M=1/2*conductivityE0^2(hl)(1-e^(h/l))/M
Now we can retrieve the initial E field(E0), and can get the E field for depth z. The general process would be like this, when more parameter were provided, you may be able to modify it to a more accurate version.