孤城浪子的地盘

2.4G全向天线资料

圆筒天线的直径、振子、长度的计算值可在下面网页直接输入计算，网址：http://www.saunalahti.fi/elepal/antenna2calc.php
             相关WIFI天线制作网站：
             http://hi.baidu.com/ichi/blog/item/361ccaea1674d9d3d439c900.html
             http://www.binarywolf.com/249/
             http://www.qsl.net/ve3rgw/corner.html
             http://www.turnpoint.net/wireless/cantennahowto.html
             http://trevormarshall.com/biquad.htm
             http://www.xaviervl.com/Antenne/Bi-quad/index.html
             http://www.usbwifi.orcon.net.nz/
             几个制作2.4GHZ天线的网站
             http://www.saunalahti.fi/elepal/antennie.html
             http://www.frars.org.uk/cgi-bin/render.pl?pageid=1058
             http://martybugs.net/wireless/biquad/
             http://trevormarshall.com/waveguides.htm
             http://www.guerrilla.net/gnet_2_4ghz.html
             http://seattlewireless.net/index.cgi/CardboardHorn

            

http://www.dlinkbbs.com/forum-74-1.html要注册，还不错

            

http://www.meshmea.net/articles/wlan/index.html
             http://www.meshmea.net/articles/wlan/antenna/diy/index.html

            

Wi-Fi 2.4G 15DBi全向天线图纸

来源：http://info.awmn.net/users/images/stories/Library/Handmade/helical-helix%20antenna%202_4%20GHz%20HOWTO.htm

有空再翻译

Abstract  
The helix antenna, invented in the late fourties by John Kraus (W8JK), can  be considered as the genious ultimate simplicity as far as antenna design is  concerned. Especially for frequencies in the range 2 - 5 GHz this design is very  easy, practical, and, non critical. This contribution describes how to produce a  helix antenna for frequencies around 2.4 GHz which can be used for e.g. high  speed packet radio (S5-PSK, 1.288 Mbit/s), 2.4 GHz wavelans, and, amateur  satellite (AO40). Developments in wavelan equipment result in easy possibilities  for high speed wireless internet access using the 802.11b (aka WiFi) standard.  
  

Theory in a birds eye  view
The helix antenna can be considered as a spring with  N turns with a reflector. The circumference (C) of a  turn is approximately one wavelength (l), and, the distance  (d) between the turns is approx. 0.25C. The size of the  reflector (R) is equal to C or l, and can be a  circle or a square. The design yields circular polarization (CP), which can be  either 'right hand' or 'left hand' (RHCP or LHCP respectively), depending upon  how the helix is wound. To have maximum transfer of energy, both ends of the  link must use the same polarization, unless you use a (passive) reflector in the  radio path.
The gain (G) of the antenna, relative to an  isotrope (dBi), can be estimated by:  

G = 11.8 + 10 * log {(C/l)^2 * N *  d}  dBi                (1)