{http://martybugs.net/wireless/images/wg_completed.jpg Both types}



Slotted Waveguides are a common type of antenna, for more information go to (http://www.trevormarshall.com/ http://www.trevormarshall.com/)



A variation is the (http://members.iinet.net.au/~clark/FreeNet/Waveguide/ Downpipe Antenna)



The above waveguides side by side -- (http://martybugs.net/wireless/antennacomp.cgi Antenna Comparison Testing)