how is antenna efficiency calculated

I know that we can select antenna efficiency in the report? But what should the antenna efficiency plot against? PHI, THETA or FREQ?

Can anyone send me a tutorial on this? Thanks

Hi wesleyclone,

Usually we go for efficiency ,once we know the s parametrs and there by the resonace of the antenna .So ,you know the frequency at which the efficiency is needed and regarding phi and theta ,you can opt for them or not .I guess its better to calculate the efficiency by defining the whole sphere.

HFSS can do this automatically... there is a tutorial here

http://www.emtalk.com/tut_1.htm