ISM BAND DIRECTIONAL ANTENNA

Hi Friends,

I need to contruct ISM BAND DIRECTIONAL ANTENNA For linking two Wireless LAN's. Can anyone give me details how to construct directional antenna. How can I measure the gain of antenna? Please help me.

Check this: h**p://www.edaboard.com/ftopic40930.html

Measurement is not so easy. You basically you measure by comparison with another, reference antenna. Measure the radiation pattern of your antenna and reference antenna with the same probe antenna. If you know gain of your reference antenna you can calculate the gain of your antenna under test by comparison of received power. Measurement should be performed in an anechoic chamber.

If you would be interested in very high accuracy, in the measurement procedure you should take into account input mismatch. However it shouldn't change your gain by more than 0.5dB (if both your and reference antennas are quite well matched).

regards,
jerzyg