bowtie for uwb purposes

Hello everyone...,

I want to make antenna bow-tie for UWB, actually for microwave sensing,
antenna that have VSWR < 2 in 2 -14 GHz frequency range, i'm newbie of HFSS.
can anyone help me:

1). The first i have to do to design Bow-tie antenna in HFSS, what is the box is for? (I see many example using box for design antenna).

1). What actually the essential of design bow-tie from the materials, what materials combination from dielectric, groundplane, and substrat.

2). What is the bow-tie design that can result acceptable VSWR (<2) from 2 - 14 GHz?, is that trial and error, or anyone have some tips?

Thanks
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