coupled line filter for s band

i want to design coupled line filter for 2.45ghz with lower cutoff 1ghz and upper cutoff 3ghz......in ads. how i should start?

that filter should be broadband. You can search the broadband filter in this forum, I remember that should have such topic.
good luck.

thanks tony_lth...i will check that

I wouldn't try to make a really broad band filter with coupled lines, your gap will have to be really small. The design would be impractical, there are better topologies for practical design. A series of shunt resonators separated by Z0 quarter wave TLs might be practical.

One convenient way to design such a wide band filter would be cascading low pass and high pass filters with LC designs. Coupled resonator is not practical for such a wide bandwidth.