"Wor" wrote in message ...

I think "beam" i spolitical name. Antenas with directivity was made by
japanese scientists Yagi and Uda. And after WWII Japan was not very popular
between Americans. So, they name such antennas "beam"

I don't know the correct definition, but my definition is an antenna array
with inline elements.
Those elements can be parasitic or driven. And they can be dipoles, quads,
triangles or whatever.