This covers the frequencies of 2,400 MHz through 2,440 MHz. Our goals were to achieve a higher gain than the internal card antenna located in a common PCMCIA wireless card, smaller size and greater portability than current external antennas and omni-directionality for use in a mobile enviroment.
http://www.timgineer.com/index.php/?page=projects&old_project=80211b_Discone
The resulting antenna has about 22 db of gain, and is fed with 50 ohm coaxial cable. Usually LMR400 or 9913 low loss cable is used if the source is more than a few feet from the antenna. The range using two of these antennas with a line of sight path is around 10 miles at full bandwidth.
http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html
Here we make a cheap antenna (more of an antenna add on) that boosts a wireless signal in one direction by at least 50%. I saw my speeds increase from 800kB/s to 1200 kB/s and my signal strength increase from 14dB to 21dB.
http://www.elephantstaircase.com/wiki/index.php?title=ParabolicAntenna
The Primestar dishes are high gain, low cost, parabolic reflectors with an offset feed. They have superior sidelobe performance when compared with a wire grid antenna, reducing the chance that somebody off of the axis of your link will be able to interefere with it. But they are hard to feed because the f/d ratio varies from about 0.5 in the vertical axis to 0.8 on the horizontal axis.
http://trevormarshall.com/biquad.htm
Wireless 802.11b are becoming very popular these days, so are the art of extending the range of such devices. Most people when begin to know what is wireless networking and that it uses antennas to extend its range thougth on that old parabolic dish they used to watch TV. Surely it's posible to use it for 2.4Ghz that is what 802.11b standard uses.
http://www.sorgonet.com/network/biquad/