Dave Platt wrote:

Is it any more efficient to use copper foil or PCB material as the reflector
rather than wire?

I believe not.

PCB material will probably be less efficient - standard FR-4
fiberglass-and-epoxy has significant losses at 2.4 GHz. Also, the
presence of the FR-4 will change the effective length/diameter of the
reflector loop... you might have to change the loop diameter to
compensate.


I would think so, at 2.4Ghz there is, no doubt, "only skin effect."
Although, I doubt you would notice a great change in efficiency, it
should be prove-able, at least on paper. The biquad uses a solid
reflector plate for good reason, wire is cheaper/easier to obtain. If
the foil side faces the element, I should doubt any rf gets past it to
the fiberglass-epoxy to be "lost" in efficiency.

Foil would probably be bit less efficient than wire, assuming that the
width of the foil was the same as the diameter of the wire - less
surface area for the current to flow through, and perhaps more current
crowding to the edges of the foil due to skin effect. It'd also be
significantly less rugged.


My statement above applies here ... all the wire element can "see" is
reflector, with foil.

Once again, neither of these losses of efficiency is likely to be
terribly important in this application, but why run the risk?

I'd just stick with solid copper wire of a reasonable diameter/gauge,
as it'll be electrically efficient and mechanically strong and rigid,
easy to get, and inexpensive.


Tear apart some LNA/satellite feeds to the dish, you will not see them
using wire reflectors there; I think there is good reason.

Just my opinions drawn from my readings/study, looking at commercial
equipment and hands-on ...

One thing I do totally agree with, it WILL work well with just a wire
reflector.

Regards,
JS