RF Cafe Software

RF Cascade Workbook 2005 - RF Cafe
RF Cascade Workbook

Calculator Workbook
RF Workbench
Smith Chartâ„¢ for Visio
Smith Chartâ„¢ for Excel
RF & EE Symbols Word
RF Stencils for Visio

About RF Cafe

Kirt Blattenberger - RF Cafe WebmasterCopyright
1996 - 2016
Webmaster:
Kirt Blattenberger,
 BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:
 AirplanesAndRockets.com

Try Using SEARCH
to Find What You Need. 
There are 1,000s of Pages Indexed on RF Cafe !

Electronics World Cover,TOC,and list of posted Popular Electronics articles QST Radio & TV News Radio-Craft Radio-Electronics Short Wave Craft Wireless World About RF Cafe RF Cafe Homepage RF Cafe in Morse Code Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs Twitter LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes AN/MPN-14 Radar 5CCG Notable Quotes App Notes Calculators Education Magazines Software,T-Shirts,Coffee Mugs Articles - submitted by RF Cafe visitors Simulators Technical Writings RF Cafe Archives Test Notes RF Cascade Workbook RF Stencils for Visio Shapes for Word Thank you for visiting RF Cafe!

Coilcraft Filter Designer by Nuhertz

Coilcraft recently announced a new version of their 'Filter Designer' software, which is a customized version of the Nuhertz Technologies' 'FilterSolutions' filter synthesis and analysis program. Filter Designer will generate schematics and response curves for 3rd-, 5th-, and 7th-order lowpass Elliptic filters that incorporate Coilcraft inductors. The functionality is therefore somewhat limited and, honestly, is probably more of an advertisement for the full-blown commercial version of the software, but I did find one aspect very instructive. If you have built a filter using real-world components, then you know how sensitive inductors are to package configuration, wire winding characteristics, and placement on the circuit board. A simulation can be utterly worthless in predicting the performance of a prototype filter if the modeling is not done precisely to accommodate particular component parameters. That's where having Coilcraft incorporate its own well-characterized inductor models into the program is a great advantage. 

To illustrate the effects of package parameters on filter performance, compare the two screen shots of the default circuit when the program is fired up. The top plot uses Coilcraft's 0603 surface mount package style while the bottom plot uses the 0302 package. Note the much higher insertion loss with a major slope going into the stopband, and the significantly degraded return loss throughout the passband. The problem might be partially caused by the series inductors that were automatically selected being limited to 34 nH in value because that is the largest value available in the 0302 package. All the other capacitor and inductors remain the same as with the 0603 package implementation.

To test that theory, I changed the passband to 300 MHz so that smaller inductors would be chosen, and discovered that both the 0603 and the 0302 package versions use the same value inductors within 1 nH. That resulted in a much smaller difference between the two plots, although the larger package size still resulted in lower insertion loss and better insertion loss as might be expected due to a larger diameter wire.

Coilcraft Filter Designer by Nuhertz - RF Cafe

The lesson here is when using software that prefers one manufacturer's parts over another's, to be sure to note component values when comparing presented implementation options. Space restrictions could be forcing you to use small components that might be available from another supplier but are not included in the database of vendor-customized software.

One solution is to buy the vendor-agnostic full version of Nuhertz Technologies' 'FilterSolutions,' or one of the other programs like those offered by NI (formerly AWR), Keysight Technologies (formerly Agilent, formerly HP), AADE Filter Design (now free), and others. Many of the older free filter synthesis programs that did a great job for most cases were compiled as 16-bit and therefore will not run on 64-bit microprocessors. There might be some good smartphone apps out there today, but I have not researched them. Please send me an e-mail if you know of any worth mentioning.

 

 

Posted August 31, 2015