This will excite a different mode than what was shown above. Now suppose you fed the cantenna from the back instead of the bottom. This should be one-quarter of a wavelength (in the guide!) from the back of the can, and it will excite the TE11 mode: electric fields are plotted in red and magnetic fields are plotted in blue. The grey rectangle is the cantenna, with a small green colored coax cable attached with the center conductor extending into the can.
Shown below is a side view of the waveguide and feeding coax. the “dominant mode” for circular waveguide. Shown below is one transverse electric (TE) and one transverse magnetic (TM) mode – the main types for circular waveguide.įirst let’s look at the TE11 mode a.k.a. Also, different modes have different radiation patterns. This is for several reasons: different modes actually travel at different speeds down the waveguide, known as “dispersion.” This can cause a problem for signals by spreading out pulses making them harder to receive. Inside waveguides, electromagnetic fields can only exist in certain patterns called “modes.” The best cantenna designs excite one and only one mode. ( ) This is a little Doppler radar kit that I’m putting together. I have a slightly different application: The Ramsey SG7 Speedy Radar Kit operates at 2.6GHz. 802.11n can use both 2.4GHz and 5 GHz, but you can get away with only the 2.4GHz signal - it propagates better over long ranges anyway. Most 802.11 standards fall into this band: 802.11b and 802.11g use 2.4GHz.
#CANTENNA CALCULATOR WIFI FREE#
This could be useful for connecting a laptop to the internet in a remote location or connecting to a free Wi-fi network from your home. You excite the cantenna with a coaxial cable an d it will transmit your signals – it’s as simple as that!Īs luck would have it, many can sized cylinders are good for the 2.4 GHz ISM band.
The length and diameter of the t ube determine t he antenna’s radiation pattern. You pick the diameter of the tube accordin g to the frequency band you want to work in. Practically speaking that just means a hollow metal tub e excited in a way that radiates electromagnetic e nergy. In antenna terminology, this is an “open-ended waveguide”.
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