Antenna active or passive elt

[koushikr_in]

is antenna an active or passive elt?

 

[frannk]

Passive, the gain you get is relative to either an isotropic(dBi) radiator or dipole(dBd). Should think in terms of directivity instead og gain.

 

[brmadhukar]

Hi,
Any antenna is just some form of resonator. If you use an amplifier immediately after the resonator it is an active antenna otherwise passive. Active antenna increases the signal power immediately at the point of reception. Noise figure is one more term you need to be aware of.
B R M

PS: These may be asked in elementary questions section.