Here is a sector antenna you can build for Wi-Fi 2.4GHz ISM band. This antenna is suitable for use in Computer Radio LANs conforming to the IEEE 802.11b/g standard – better known as Wi-Fi. It can be used on an Access Point (or wireless Router) or Wifi client with equal benefits.
Properties
This antenne has the following properties.
Frequency 2,4 to 2,5GHz
Impedance 50 Ohm @ 2,45GHz
VSWR < 1:1,5
Polarisatie Verticaal
Vertical beamwidth (-3dB) 15º
Horizontal beamwidth (-3dB) 125º
Connector: Female-N type (50 Ohm)
For the reflector, use 495x62mm of Copper-clad circuit board. Copper side must be on the same side as the radiator (I use double-sided PCB).
Drill a hole in the centre to accept your N-Type connector. I Use one that comes with rigid coax attached. The shield of the coax should extend to 28mm above the surface of the PCB. The centre conductor must extend 5mm more. Drill 4 holes to attach the studs to the reflector.
Bend the two radiators. Do not forget to slide on the PE studs before bending. Remember: It is the amount of wire you use that is important, not the final dimensions after bending!
http://pe2er.nl/wifisector/index.htm
