Richard Fry wrote:

I don't know your definition of an "expected bandwidth," but for a
reality check--many forms of panel antennas used in FM and TV broadcast
transmission have 20% or better SWR bandwidth, and radiate nearly every
watt that can be delivered by the feedline with almost NO "matching"
losses. They have been in routine use for decades at master antenna
transmit sites all over the world.

Now shrink down those antennas by a factor of, say, 10 in size. Think
they'd still do it? If so, you're the natural prey for the charlatans.

In product development, we say fast-cheap-good, pick any two. With
antennas it's small-efficient-broadband, pick any two. "Small" is, of
course, always in terms of wavelength when it comes to antennas.

Roy Lewallen, W7EL