Post subject: Wideband Filter Posted: Tue Nov 27, 2007
Joined: Sat Jun 16, 2007 12:26
Can anyone tell me:
Why the Return Loss
performance is poor in Wideband Filters?
is it difficult to get good Return Loss performance in Wideband
Post subject: Posted: Tue
Nov 27, 2007 4:01 pm
Joined: Mon Jun
27, 2005 2:02 pm
Wideband filters are those with a BW>10% of the center
The reason for that is the same as why it is hard
to design a wideband filter with low insertion loss. When you design
a wideband filter, more resonators are required which increase the
insertion loss and thus the return loss.
Post subject: Posted: Thu Nov 29, 2007 6:49 am
Joined: Sat Jun 16, 2007 12:26 am
Thanks for your reply..
Can you please
explain it with the help of circuits? A circuit containing combination
of L and C and some tank circuits.
Post subject: Posted: Sat Dec 01, 2007 12:16 pm
Joined: Mon Jun 27, 2005 2:02 pm
The following article mentions this
issue. It describes distributed (printed) filters. The principle
is the same for both distributed and lumped filters.
Post subject: Posted:
Mon Dec 24, 2007 9:25 pm
Mar 15, 2005 11:43 pm
I agree with the above posts.
But keep in mind
that by adding more resonators, there will be more insertion loss
The difficulty in getting good Return Loss performance
in Wideband Filters is somehow related to the Q concept.
depends how good you want the performance is. The smaller insertion
loss and the higher return loss require higher Q, which means it
will give sharper response.
I hope it helps.