Design Terahertz Antenna with CST Microwave

Hello everybody . i hope you be fine

I have a question about how to design Terahertz Antenna in CST Microwave
suppose a Bow Antenna which is designed in band 100GHz to 3THz , I want to know that how i can excite in a Electromagnetic Wave in feed of this antenna that i be able to determine the power of this signal

( I mean does CST have ability to define a electromagnetic waves with input power ?)
with more explanation, I want to design an terahertz antenna(any structure) which i able to excite a Terahertz Wave with High power up to 60 watt in input of this antenna and after simulation I want to calculate

1 - calculate the output gain of this antenna

2 - extract the Changes of radiation efficiency in terms of times

3 - extract the radiation range in terms of meter ( i means how much does this antenna radiate terahertz power according to output power)

thanks in advance