reconfigurable antennas

hi every one,
can any one please help me to understand that what's the difference between the dual band and frequency reconfigurable antenna.

as far as I have understood is that with dual band ,one can use two frequencies but for tuning between those two frequencies , need a diode switch etc, resulting in frequency reconfigurable antenna.

please acknowledge me, am i correct or not.

Thanks

A dual-band antenna is designed to operate at two frequency bands at the same time. Reconfigurable antennas operate at two or more frequency bands but not at the same time. To configure such antenna for a certain frequency, switches and/or tuning elements like varicaps are used.

thanks alot.
so if I have to choose among the dual band and frequency reconfigurable antennna, which antenna has better performance

Better performance depends on actual application/implementation.

A re-configurable antenna may be harder to realize in practice than a dual band antenna.

Even the antenna is dual band, but you may need the switch to fine tuning each band.

The difference between these 2 kind of antennas is not the performance, but the application. The dual-band antenna is proper for the application that you wanna used 2 different frequency band simultaneously but the reconfigurable one is proper for any application that used in various frequency bands (but not simultaneously: each band at a time.).