Antenna Help

Hi all,

first of all, i have never design antenna before. however, in my course work i have to characterize a matrial in the Thz range. for that i needed to design an antenna with the material that i am trying to characterize at the end of the antanna and look at the transmission and reflection coeficien .
can someone help me design this antenna? specially the waveguide lenght that feed the antenna.
thanks in advance.

PS: 500Ghz<f<1.2THz, Theta = 3deg.

I think the antenna size should be at the same lever as a quarter of its working wavelength.
I think it will better if you give your specifications for the antenna parameters, like S parameters and voltage standing wave ratio.

I think the antenna size should be at the same lever as a quarter of its working wavelength.
I think it will better if you give your specifications for the antenna parameters, like S parameters and voltage standing wave ratio.