why antenna should always be in resonance with applied freq.

hi all

Please tell me why antenna should always be in resonance with applied freq.

Here I think because resonance means XL equals to XC so antenna should not give any impedance with the applied frequency so it should always in resonance with the applied frequency.
this is want I think about this
pleasetell me it is wrong or right
or letme know if any other exaplanation is there for this

Thanks & regards
gbaerf

using an antenna at resonance means the structure is purely resistive and thus lossy (radiation). when there is a reactance some of the energy applied is "stored" within the structure.

best regards.

Thanks that helped me
Regards/gbaerf