How fringing field affect current in antenna

[alfarooqui]

Hi

What is the effect of fringing field to current in an antenna? So far i know radiation depend on current. So there must be some relationship between current and fringing filed.

Regards
Farooqui

 

[biff44]

well, of course. If you have a microstrip patch antenna, for instance, you must forshorten the patch length x width to compensate for the fringing capacitance along the patch edges. Otherwise it resonates lower in frequency than desired.

 

[rrumpf]

They are essentially the same thing, two sides of the same coin. Any time you have a current in a wire, there is a magnetic feild surrounding it. The fringing field, or near-field, around an antenna is due to the charges stored in the conductors and currents moving through them. In fact, if you know the current, you can calculate the surrounding magnetic field. Likewise, if you know the magnetic field, you can calculate the current.