The "Method of Moments" (MOM) makes no assumptions about
current distribution on a radiator; it computes the current distribution.
The radiated field is then calculated based on the current distribution.

Frank

Yes it does but as always one must review the basis on which formula
is formed and conditions expressed
One of these conditions is that current flow is sinusoidal which
cannot be true because of leakage ( radiation)
per unit length of the radiator. If on compares the current flow of a
full wave radiatior to a fractional wave
current flow this becomes very obvious especially when either of them
is compared to a true sino soidal curve
Cheers Frank

None of the conditions assume current (distribution) on a radiator is
sinusoidal. It can be anything, not even remotely sinusoidal, and
frequently has discontinuities (such as a "unit step function" in the
case of a shunt fed, gamma matched, grounded tower, for example).

The theory behind the "Moment method", in the case of NEC 2,
is in the public domain, and available he

http://www.nec2.org/other/nec2prt1.pdf

Frank