NEC-LIST: Mutual Coupling in Finite Element Array

Dear All,

I am analyzing the performance of a 5 x 5 rectangular
array using NEC2. The method used is same as usual - Without any loading
on any element, sequentially excite each element, while reading the feed
segment currents of the other passive elements - to obtain the appropriate
admittance parameters.

Then I am plugging these Y parameters
in the Cmax formula given in NEC documentation to get maximum coupling
between any 2 elements for such a rectangular array.

Now, I am
also parametrically varying the separation between adjacent elements from
0.1*lamda to 1.0*lamda, as also, for a given separation, I am phasing the
array beam from zenith to horizon (0 to 90 degrees) in steps of 5 degrees.
For each of these I have to generate a NEC file.

The
question is this: For some NEC files, the Y parameters that NEC
provides me with, yields a value of "L" which is more than
"1".
Now, since

Cmax = [1 - sqrt(1-L^2)]/L,

this gives me a complex value for Cmax. Basically, Cmax is a power
transfer ratio between the excited and passive antenna, and as such cannot
be complex.

Is it possible for "L" to be greater
than "1"? If no, what does it indicate, I mean, what, if any, is
the physical significance of "L"?

Kindly
share your information about the above.

Thank you in
advance.

Nikhil Mehta
Research Engineer
                 
 
Raman Research Institute
Sadashivnagar Bangalore 560
080

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