Coaxial cavity filter with folded topology.

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.

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.

A demonstration of advanced filter synthesis concepts that can be applied to your future designs to meet the demand for stringent requirements. Couplings Designer makes it easy.

• Transmission zeros – the importance of transmission zeros and how they can be engineered to create advanced filter responses for increased rejection and/or group delay equalisation.
• Non-resonating Nodes, NRNs – the relatively new building block, a non-resonating node or NRN, can be used to create new advanced filter topologies.
• Predistortion – the benefits of predistortion when size and cost requirements are stringent.
• Resonator Q distribution – the importance of distributing the resonator Qs correctly when reducing the size of a filter implementation.
• Topologies – the concerns involved in choosing an appropriate topology, especially the sensitivity issues inherited in certain topologies.
• Optimization – the power of combining two synthesis methods, exact approximation with prescribed zeros and optimization, to synthesize a coupling matrix according to a specification.

Releasing Couplings Designer 1.2 for iPhone and iPad! Features and bug fixes since the previous version:

• fixes a bug that made seeding new coupling matrices fail
• fixes a bug where the response plot was blank
• improved response plot

Buy it at the App Store or try Couplings Designer Lite for free today! Learn how this app can take your filter designs forward here…

Releasing Couplings Designer 1.1 for iPhone and iPad! Features and bug fixes since the previous version:

• iPad support (scaled up version)
• supports bandstop response
• prescribed transmission/reflection zeros
• predistortion
• easy sign-change of couplings

Buy it at the App Store or try Couplings Designer Lite for free today! Learn how this app can take your filter designs forward here…

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.
 

Try Couplings Designer LITE for free on your iPhone!

 
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.