Wave length and the Pringles can antenna

Thread Starter


Joined May 3, 2006

My questions concern a better understanding of the design of a Pringles can 2.4GHz antenna. Information on this design can be googled.

My questions are:

1. The design found on the web uses director dimensions for Lo (for 2.4GHz in free space) but the wavelength in the can should be Lg so shouldn't the director be dimensioned for Lg?

2. The location of the driven element is probably at or near 1/4 wavelength from the reflector which indicates an Lg which doesn't match the math. Can you explain this? I'm sure there are many variables affecting what goes on inside the can and I'm wondering if the relatively thin metalization of the inside of the can is suitable to cause a standing wave but doesn't really act like a normal metal tube waveguide of similar dimension. Therefore maybe the math doesn't apply. Lg=1/SQRT((1/Lo)sq - (1/Lc)sq) Where Lc is ~ 1.7Diameter of the tube.

I haven't built one of these yet but I suspect it works.