finding dielectric functions

["Brian T. Schwartz" <Brian.Schwartz@Colorado.EDU>]

Hi,

I'm trying to use LC to find the dielectric function of a periodic
structure.  My plan is to

1.  put a probe at the input and output of the structure,

2.  define an incident, reflected and transmitted pulse,

3.  use the S-parameters with Fresnel reflection/transmission coefficients
to find the refractive index.

(Needless to say, the dielectric function, "epsilon," is the ratio of the
electric displacement to the electric field in the material, as a function
of frequency, epsilon = D/E.)

As a physics/optics guy, I've never used S-parameters before. Yet, it was
easy to show that S11 = r, the reflection coefficient, and S21 = t, the
transmission coefficient of the structure with the input at one side.

So my question is:  How can S11 and S21 be > 1?  That's what LC is
telling me, but I don't know how to interpret that.  I think I'm defining
my pulses correctly regarding start and stop times.

Also, if there is an easier way to do what I'm trying to do, please tell
me.

Sincerely,

Brian Schwartz