Building a 12dB Wifi (5.8GHz) Antenna
If you need a 5.8GHz directional antenna, the Helix is a little marvel and easy to build.
I used some 1mm epoxy, 2 pieces without cupper for the holding the helix and one round piece for the reflector.
The two cupperless pieces have holes at the precise position where the cupper wire (1.2mm diam) will fit.
The round pcb board has holes to fix the antenna guide and the SMA connector that will be fixed from the back side.
The back part holding the two other epoxi pieces give strong solidity to the antenna.
Entering the pre-formed wire was not an easy job, it too me 3 hours to have it fixed.
Bigger holes would have made the job easier but less precise.
To test the antenna, I used a slightly modified TP-LINK router, as shown, the fix internal antenna was replaced by a pig-tail with SMA connector.
The overall solution easly makes a 11-12dB antenna, very directive and efficient.
* Design frequency 5800MHz
* 8 turns
* Wavelength 0.23
* Internal diameter 17-17.5mm
* Wire diameter 1mm
* Coil spacing 11.8mm
* Reflector 40mmx40mm
* Wave Trap size 6.5mmx3.2mm
* Wave Trap spacing from feed point 2mm
* Feed point height 2.5mm (wire center), maintained over 1/4 turn
Thanks to Michael/Mictronics who did the original message