Doesn't sound like you're missing anything. We are just talking about different things. Common disease, here! Certainly, for the same directive gain, the aperture of an antenna is smaller at higher frequencies. However, I'm not holding gain constant, but size.
If the two antennas are the same physical size (and properly phased) the size in wavelengths -- and thus directive gain -- will be greater at the higher frequency. You may have two devices with nominal 30 cm-long antennas, one for 915 Mhz, two half waves collinear, close spaced, and one for 2.4 GHz, with 5 half waves. The 2.4 GHz antenna's gain will be about 6 dBd, I think, more than the 915 Mhz antenna at about 2 dBd. But this may not be why the limit levels off. Cortland ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
