The reference antenna used for calculating the gain in HFSS

anyone help me
i want to kn that what is the reference antenna used for calculation of the gain of the antenna in the HFSS ? is it Isotropic antenna or half wave dipole antenna?
plz tell me...............

The gain is calculated by directivity and efficiency. It is in dBi.

HFSS provides several "versions" of gain. Read online help carefully to see the distinctions.

You can go into the post processor, far field section and look at the report options to see the choices. I usually find total gain (in dBi) to be most useful. Just an additional comment, be careful as some to the plots do not default to dB and some do. Just keep an eye on that.

After simulating the antenna gain, is there any efficiency method to measure it for comparing it with the simulated one ?

Thx !