Calculated useing 2.437 ghz (channel 6) for center frequency:

Lower cut-off frequency should be lower than 2400 MHz

Upper cut-off should be higher than 2480 MHz

Circular waveguide antenna showing design values, click to enlarge.

92mm is the optimal diameter if you want to try to optimize it for flattest response across Channels 1-11
this is because it minimizes the difference in the probe position between Channels 1-11
about 2.63mm, so the SWR curve across the WiFi band is flatter.

Lc = 1.706 x D
Lo = 300/F
Lg = 1/((sqrt(((1/Lo)^2)-(1/((1.706*D)^2)))
1/((sqrt(((1/123.102174805)^2)-(1/((1.706*92)^2)))
198.441883 / 4 = 49.6104707

build a 4 barrel cantenna array

Here is something that you may want to try.
1 cantenna = 12 db -- 16X
2 cantennas = 15 db -- 32X
4 cantennas = 18 db -- 64X
things you need to know are:
makeing the cophase harness
how far apart to mount the cans
this is how i did it and it really works.
cophasing beams you need an odd multiple of 1/4 wavelength coax.
i use RG6 with crimp on F-connectors.
velocity factor of RG6 is .82 (-- 300/f=123.102mm X .82=100.943mm
/4=25.2359mm --)
i used 11 -- quarter wavelengths 277.595mm so i cut the coax "shield to
shield" 10 15/16"
to make the combiner i used a 4-1 diseqc switch . had to tear it apart
gut it out and rewire it this way.
the short coax pieces are RG58/u "velocity factor=.66" cut to 20.3mm or
13/16" is close
eanugh.

build the center solder point first flux and heat needed ------->

female F-connector used for probe

The distance between the cantenns "center to center" 54/beam width * Lc
beam width of cantenna is 30 degrees
54/30*123=221.4 mm