100MHz - 1GHZ Bowtie Antenna

Is there a way to design a flat bowtie antenna from 100MHz to 1GHz? When I design using CST, I can't cover the whole bandwidth no matter how big i make the antenna. The only way it covers more badwidth is if I go up in frequency. I'm just asking if it's possible.

I can probably buy a bicone, but every bicone for that frequecny range is very expensive

Thanks