Homepage - RF Cafe
Webmaster: Kirt Blattenberger | KB3UON | Sitemap | ©1996-2014     Visit RF Cafe on
      Menu below is just a small sample of what is here!          Visit RF Cafe on Facebook Visit RF Cafe on Twitter Visit RF Cafe on LinkedIn
Custom Search
More than 10,000 searchable pages indexed.
•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

Wideband Filter - RF Cafe Forums

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 you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


Antonio
Post subject: Wideband Filter Posted: Tue Nov 27, 2007 6:42 am

Captain


Joined: Sat Jun 16, 2007 12:26 am
Posts: 12
Can anyone tell me:

Why the Return Loss performance is poor in Wideband Filters?

Or

Why is it difficult to get good Return Loss performance in Wideband Filters?


Top

IR
Post subject: Posted: Tue Nov 27, 2007 4:01 pm

Site Admin


Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hi Antonio,

Wideband filters are those with a BW>10% of the center frequency

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.


Top

Antonio
Post subject: Posted: Thu Nov 29, 2007 6:49 am

Captain


Joined: Sat Jun 16, 2007 12:26 am
Posts: 12
Hi IR,

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.


Top

IR
Post subject: Posted: Sat Dec 01, 2007 12:16 pm

Site Admin


Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hi Antonio,

The following article mentions this issue. It describes distributed (printed) filters. The principle is the same for both distributed and lumped filters.

http://www.eng.jcu.edu.au/Staff/Profile ... 81-Fil.pdf

Top

Jeanalmira
Post subject: Posted: Mon Dec 24, 2007 9:25 pm

General


Joined: Tue Mar 15, 2005 11:43 pm
Posts: 65
Location: Singapore
Hi Antonio,

I agree with the above posts.
But keep in mind that by adding more resonators, there will be more insertion loss resulted.
The difficulty in getting good Return Loss performance in Wideband Filters is somehow related to the Q concept.
It 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.

Regards,
Jean








Posted  11/12/2012
A Disruptive Web Presence

Custom Search
Over 10,000 pages indexed! (none duped or pirated)

Read About RF Cafe
Webmaster: Kirt Blattenberger
    KB3UON

RF Cafe Software

RF Cascade Workbook
RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
RF system analysis including
frequency conversion & filters

RF & EE Symbols Word
RF Stencils for Visio

Product & Service Directory
Personally Selected Manufacturers
RF Cafe T-Shirts & Mugs

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel
Your RF Cafe Progenitor & Webmaster
Click here to read about RF CafeKirt Blattenberger... single-handedly redefining what an
                                 engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem! (Seize the Day!)

5CCG (5th MOB): My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website