Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
I agree with laza that a suitable choice is the discone antenna. It's omnidirectional with "8" radiation pattern as lbda/2 dipole. Can cover frequencies fmin:fmax~1:4 so no problem for your band. I can send you detailed info about design.
First I need to know if the 100MHz bandwidth is for VSWR( 2:1 or 3:1 ) or Gain -3dB from center Frequency.
Next the kind of pattern, ominidirectional or directional.
If directional, front/back ratio, gain etc.
But I can estimate something: If the array you are looking for is directional, the best choose is a Log Periodic Dipole Array.
Try to use a double boom to do the phase shift and feed the elements. I had best results with that arrange.
Hope to help