Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
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Below are all of the forum threads, including all
the responses to the original posts.
Post subject: microstrip BP filter from an elliptic prototype
Posted: Sat Dec 31, 2005 8:20 am
Aug 14, 2005 3:24 pm
I should design a narrow band BP filter on microstrip in s band.
the requiered degree of the filtr using chebyshev prototype is 21 but
using elliptic is just 7. but I can't find a systematic way to depart
from this elliptic LP prototype to a BP common filtr type on microstrip.
All I found is for all-pole filtrs not for an elliptic type.
may anyone help?
Post subject: Posted:
Sat Dec 31, 2005 9:51 am
Joined: Mon Jun
27, 2005 2:02 pm
In general you reach to any type of filter from the LP prototype
by using the Koruda transformations. To transfer to microstrip from
lumped elements you will have to use Richards transformations.
Nowadays you can use a simulation tool which does all this work
for you and provides you with pretty accurate results. You will need
to use both linear simulation to tune your microstrip length and width
and coupling between the resonators and also to use an EM simulation
to see how the filter performs inside walls.
My preferred choice
would be Eagleware GENESYS (Now part of Agilent). This tool has synthesis
functoins for lumped and distributed filters in which you can define
the topology, required attenuation etc and get a circuit schmeatic including
values. It also has an EM simulation capability.
Post subject: Microstrip Elliptic-function filtersPosted:
Sat Dec 31, 2005 7:48 pm
Just a small point: If you google for the
transformations, you need to type in "Kuroda" not "Korodah".
Post subject: Posted: Sat Dec
31, 2005 10:03 pm
Joined: Mon Jun 27,
2005 2:02 pm
Thanks for the correction
guest. It should be Kuroda.
For you eastern here is a link to
an application note that may be useful: