Apertures without a ground plane behind them give you the most bandwidth. A 3 dimensional bicone antenna can do that easily. It will have to be 30" tall though.
I made a 1-40 ghz bicone with -5 dB worst case rtn loss that was 3" tall and 5" diameter. Scaling that x10, although the diameter doesn't need to be 5x10 inches.

A printed option is the flattened equivalent to the bicone. One with a ground plane is shown in IEEE AP magazine, April 2003, page 901 shows a 0.8 to 10.5 Ghz notch (3:1 VSWR) on a ground plane antenna.

A standard LTSA/Vivaldi/Notch antenna can do it too, so if you need omni coverage (for vertical polarization) use a flat bicone shape, and if you want higher gain at the high frequency, use the Notch antenna.

What is the application?

kch