fv = circpol2pol(cfv) converts
the circular polarization components of the field or fields contained
in cfv to their linear polarization components
contained in fv. Any polarized field can be expressed
as a linear combination of horizontal and vertical components.

Create a right circularly polarized field.
Compute the circular polarization ratio and convert to the linear
polarization ratio equivalent. Note that the input circular polarization
ratio is Inf.

cfv = [0;1];
q = cfv(2)/cfv(1);
p = circpol2pol(q)

Field vector in its circular polarization representation specified
as a 1-by-N complex row vector or a 2-by-N complex
matrix. If cfv is a matrix, each column represents
a field in the form of [El;Er], where El and Er are
the left and right circular polarization components of the field.
If cfv is a row vector, each column in cfv represents
the polarization ratio, Er/El. For a row vector,
the value Inf can designate the case when the ratio
is computed for El = 0.

Field vector in linear polarization representation or Jones
vector returned as a 1-by-N complex-valued row
vector or 2-by-N complex-valued matrix. fv has
the same dimensions as cfv. If cfv is
a matrix, each column of fv contains the horizontal
and vertical linear polarization components of the field in the form, [Eh;Ev].
If cfv is a row vector, each entry in fv contains
the linear polarization ratio, defined as Ev/Eh.

References

[1] Mott, H., Antennas for Radar and Communications,
John Wiley & Sons, 1992.

[2] Jackson, J.D. , Classical Electrodynamics,
3rd Edition, John Wiley & Sons, 1998, pp. 299–302

[3] Born, M. and E. Wolf, Principles of Optics,
7th Edition, Cambridge: Cambridge University Press, 1999, pp 25–32.