need to simulate Gaussian pulse in HFSS

I need to excite a UWB antenna with a Gaussian pulse in HFSS. I am not sure how I can do this? I see a Gaussian Beam under excitations but not sure how that is done. Could someone share their knowledge on how to get this done in HFSS FEM. I know HFSS FEM is frequency domain, but I thought there is way around this with some IFFT, etc....

Thanks.

Is there a problem with using a Gaussian Pulse excitation? If you're looking for a time domain solution, set the solution setup type to 'Transient'.