double ridged horn antenna at 2 GHz

Hello...

I want to construct the above antenna with central frequency at 2 GHz and a bandwidth from 1GHz to 3 GHz..
I have manage to calculate the dimensions for each frequency but I dont Know how to combine all this dimensions to one for the construction?
This might sound funny but if somebody is aware of the above please help me!
Is it going to be done mechanically? For example using a screw? But how? I am confused..please help me.

Thank you in advance.

Best regards,
atsou