Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine USAF Radr Shop Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Thank you for visiting RF Cafe!
Triad RF Systems Amplifiers - RF Cafe
Anatech Electronics (RF Filters) - RF Cafe

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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:


Innovative Power Products Couplers

switch matrix - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts.

-- Amateur Radio

-- Anecdotes, Gripes, & Humor

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Miscellany

-- Swap Shop

-- Systems

-- Test & Measurement

-- Webmaster

 Post subject: switch matrix
Posted: Mon Jun 06, 2005 6:36 am 

Joined: Mon Jun 06, 2005 12:38 am

Posts: 2


i am working on switch matrix in the frequency range of 18GHz.

when i interconnect the switches(electromechanical switch) in series by using semi rigid cable, return loss is becoming bad in ku band frequencies.

please give ur suggestion for improving the performance.





Research engineer


 Post subject:
Posted: Mon Jun 06, 2005 7:46 am 
User avatar

Joined: Mon Sep 01, 2003 6:59 pm

Posts: 38

Location: Boston

Can you replace most or all of your coaxial cable with waveguide? Waveguide loves 18 GHz and you eliminate the lousy connectors that coax has to use. In fact, a lot of your cable problems could be due to the connector interfaces. One way to check is to do a TDR on the path and see if your reflections are concentrated at connectors. Sometimes a judicious trimming of cable lengths can significantly reduce VSWR induced ripple and slope.

- Maxwell

 Post subject:
Posted: Tue Jun 07, 2005 12:09 am 
hi max,

thank you for your reply.I may not be able to use wave guide in system.i have to use coax only. please post your suggestion regarding connectors and cables works at 18GHz



 Post subject:
Posted: Fri Jun 10, 2005 6:43 am 
You need to minimize the cable length to under a quarter wave length in order to minimize the standing wave, you may want to scrap the cable and use sma "bullets" to connect the switches. Another trick is to adjust the phase in between the switches by either changing the length of the cable or using a phase shifter. I had a similar situation once where I was not meeting my output power requirement due to mismatch in between various modules. Like you, I was using cable. I resolved the issue by pains takingly adjusting the cable length in between each module until I obtained optimized perfromance.

Posted  11/12/2012

RF Cascade Workbook 2018 - RF Cafe
RF Cafe Sponsors
Innovative Power Products Passive RF Products - RF Cafe
Lotus Communication Systems Modular RF Component Building Blocks - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free