Ultra-wideband filter design (need help)

Hi all,

i am required to design an microscrip ultra-wideband filter with fractional bandwidth of 110%, center frequency of 6.85 GHz (3.1GHz to 10.7GHz). What is the best way to design it? Pls give me some suggestion, and do post me related paper and e-book.

I need help urgently.

Specification:
fractional bandwidth: 110%
center frequency: 6.85GHz
insertion loss: <0.1dB
return loss: >10 dB

Thanks.

You can use cascaded sections of high pass and low pass circuit.

With this wide bandwidth, HP+LP is the best choice.

is there any other method beside cascade highpass and lowpass?

see this title

also see

you can use MMR in which the higher mode in SIR can be used for a transmission pole in the passband and use strong I/O coupling. Or you can use quasi-lump filter, but I am not sure if the insertion loss can be 0.1 dB.