An aluminum coaxial re-entrant resonator is designed for high Q to meet specifications on insertion loss. High rejection is achieved with a symmetrical pair of transmission zeros implemented using an electric probe. The filter is implemented with the well known folded topology which is fairly insensitive to manufacturing tolerances. Port tuning is introduced which cuts simulation time and makes the connection to the synthesized coupling matrix transparent.
In this tutorial we will learn how to synthesize and implement a chebyshev response with a combline cavity topology using Couplings Designer. Couplings are extracted and linked to physical dimensions and then combined to realize the final filter layout. It will be shown that unintended couplings may distort the passband and stopband performance. These coupling are analyzed by Couplings Designer with a new coupling matrix that takes them into account and the final physical dimensions are tuned to reflect the change, finally retreiving the chebyshev response.
Currently looking for beta testers of a new filter synthesis tool, similar to Couplings Designer, for windows. I will select a number of testers that will be rewarded with the end product when released. You need to be familiar with coupling matrices and have experience designing filters using them, otherwise your feedback will not be as helpful. Let me know which version of windows you are running too. Sounds like an interesting deal? Write a comment or send me an email and I’ll come back to you.
Learn how to turn your synthesized coupling matrix into lumped elements for low frequency applications where waveguide and planar implementations wouldn’t make sense. It is also interesting reading for those doing miniature filters on thin film or MMIC at higher frequencies.
Couplings Designer 1.1 was released yesterday along with new features like prescribed zeros, predistortion, bandstop support, iPad support etc. However, we didn’t anticipate a bug that was introduced when updating from 1.0 which makes seeding new coupling matrices impossible. The problem is due to a compile-time error (un-initialized variable) which was only observed in the binary uploaded to the App Store and was therefore not tested. This bug has been resolved and is due for approval by Apple’s App Store review team. You may expect an update in a week’s time from today. Hold on tight couplings-crew!
A quick solution is to use a finite quality factor (and a finite effective quality factor). A “lossless” matrix can be seeded by maxing both quality factors, for instance a quality of 100000…
Update 1.2 is expected to arrive around 18th of june!
Design and synthesize modern advanced RF and microwave filters with Couplings Designer for iPhone, available today for $29.99 at the app store. Try Couplings Designer LITE for free, which has all the features but limited to 4th order filters.
Couplings Designer is a powerful and modern coupling matrix synthesis software for professional filter designs. It features an easy to use interface, tuning, a built-in coupling matrix optimizer, Monte Carlo tolerance analysis and an arbitrary topology transformer. It’s an ideal tool for professional filter engineers, system engineers and students alike. Read more about it here..
Learn about features available in Couplings Designer and take a tutorial on how this tool can assist you in your filter designs.