microwave material characterization when only S11 is known?

Hi!

Greetings!

In the context of microwave material characterization when only reflection coefficient (S11) is known:

Reflection Coefficient= noninvertible function of (Epsilon)
where, Epsilon=Epsilon_real+j*Epsilon_imag
hence, reflection coefficient is also a complex quantity.

How to find Epsilon?
Please note that all S-parameters except S11, are unknown.

Any application notes, methods or suggestions you would like to bring to my notice?

Thanks in advance !

I have used normal incidence to a boundary to find the real part of concrete permittivity.
Best is to use known materials as a reference.
Finding the imaginary part of permittivity is harder.
Please try to find my paper in the Internat.Journal of IR and MM waves, 1996. Sorry I have no copy at hand now.

Jiri Polivka

Thank you for the help but I couldn't read your research publication as it is not open to all by Springer.