Hello in hfss(ver 10)
results create reports {█(far field@radiation pattern)┤
then click ok
you first chose soulution (create reports)---(far field-radiation patterns) then click ok, you first choose solution (sweep for all frequency) then
in sweeps tab chose a frequency (one frequency) chose phi=0 or 90 and your primary sweep must be theta
in mag tab choose rE (category tab) and in quantity select rEphi and rEtheta( dB)
if don’t solve your problem up your file