about time and frequency domain

Hello!

i want to understand, what do we mean by studing or characterize an antenna in Time domain and frequency domain

thank you

Antennas are typically studied in frequency domain as most systems using them are narrow-band. Ultrawideband system, to the contrary, need similar antennas, and such are studied by their time response or domain; they are fed with very short pulses creating a very wide-band field.

to elaborate, if you go to the trouble of making something like a 200 pS wide pulse, you do not want the antenna turning it into a double hump, or some other shape distortion in the time domain.

So you really have to think thru what the phase vs frequency is doing to the time domain shape.

thank you jiripolivka & biff44, i still don't get the idea,
i'm working on smart UWB antennas, and i want to study them in time and frequency domain, just theoretically, so until now, i didn't understand how to do this properly
if u have any idea, or exampls, please show me

i will be so grateful