Lenx wrote:
we managed to calculate the microstrip filter so that one is done and
simulated. what botters us is that we didn't get ANY sort of a course
(we have to find anything on our own) and we have no clue about the
coupled lines and even less about the interdigital filter.

What books does your course use? Pozar's "Microwave Electronics" book (or
perhaps "Microwave and RF Design of Wireless Systems" -- there's some
overlap between the two with the later typically being less theoretical and
more applications oriented) is the one that immediately comes to mind for
your problem.

---Joel Kolstad