solving with CS it's radiation efficiancy be 150% !!!!!!!!!!

hello freinds
i hope that all of you be fine
i have one problem wih CST!
i design one monopole with λ\10 ground. after solving with CST it's radiation efficiancy be 150% !
this result is right?
why does CST solve rong?
how can i performe it's result?
i can send you my monopole file.
please help me
thanks a lot.
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