Approximate band attenuation 20 dB from 735 MHz to 765 MHz. Is microstrip pcb and lumped components a possible method to create this filter? In simplest form, a series paralleled inductor and capacitor.
Lumped Components serve well here..No need Microstrip structures..
The Simplest Form is a Parallel LC in series or a Series LC in Parallel or combination of those.But better solution is to use N-stage LC filter approximations ( Butterworth or Chebychev etc. ) then apply Bandstop Transformation.The best method is to use a Filter Design Program..
Any lumped component Band Pass Filter with central frequency greater than about 500MHz would be very sensitive to component tolerances, to PCB layout, and especially to temperature variations.
May need more space for a 750 MHz microstrip filter, but for sure you will have much less headache designing and manufacturing it.
Actually, I like to combine both discrete and line elements at these frequencies. But as FvM mentioned, without full specs it's not possible to estimate anything.