What's the difference between the resonant and radiation resistance in antenna ?

what is the different between the resonant resistance and radiation resistance in antenna design?
and how to calculate?

thanks!

Hi,
at the resonance the input impedance of the antenna is pure real, and it is called resonance resistance.

this resonance resistance consists of two parts, a radiation resistance which corresponds to the part of the power that is radiated, and an ohmic resistance which refers to the part of the power that is lost in the metallic or lossy dielectric parts of the antenna.

for very simple antennas like the dipoles, approximate formulas can be used to obtain the input resistance. However, for more complex antennas you have to use numerical EM code.

best regards,
Adel

hey adel...
good answer .....