Roy Lewallen, W7EL wrote:
"Either Cecil is misquoting me, or Richard is misquoting Cecil."

I apologize if I misquoted anyone. It was unintentional,

On page 239 of Kraus` 1950 edition of "Antennas" he wrote:
"It is generally assumed that the current distribution of an
infinitesimally thin antenna (l/a=infinity) is sinusoidal, and that the
phase is constant over a 1/2-wavelength interval, changing abruptly by
180-degrees between intervals."

Cosine has the same shape as sine. They are identical except for a
90-degree phase displacement. Sine starts at zero. Cosine starts at one.

Sinusoidal covers both sine and cosine shapes.

Best regards, Richard Harrison, KB5WZI