Narrow Band Microstrip BPF

Hello everyone,
I need to design Microstrip BPF from 4.9-5 GHz. The transition region is from 4.65-4.9 GHz and 5-5.25 GHz. Out of band rejection is 40dB. The insertion loss should be less than -2dB. I have tried parallel coupled line and hairpin configuration so far at different materials Er=2.2 and Er=3.55 with thickness 20 mil, but failed to get desired response. My ADS Momentum Simulated Insertion loss is greater than 5 dB. I have achieved desired bandwidth but failed to maintain desired transition region.

Please help me out to get desired response.

1: Should I use different topology? If yes than which one is better?
2: Should I use strip-line to reduce insertion loss?
3: Any other suggestions?
Thanks and Best regards,

you need a higher Q material, and need to hold very tight tolerances so that the bandwidth is repeatable, and that the center frequency is repeatable, from board to board.

obviously a waveguide resonator filter would have enough Q. A dielectric resonator puck filter probably could too. MAYBE a suspended stripline, or substrate integrated wave filter (SIW) would work well too.

Microstrip....not sure you can ever get the Q high enough. the low Q is what is causing the 5.5 dB insertion loss.

Thank you for your answer sir. In your opinion, Should I try Interdigital or combline type waveguide filter to get my desired response?

wave guide comb line , will be better,