Couplings Designer Update 1.3

Releasing Couplings Designer 1.3 for iPhone and iPad!

Get it at the App Store, new users may also want to try Couplings Designer Lite for free.


Features and bug fixes in this version: Continue reading

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iOS 7.1 related bug discovered!

As some of you have generously pointed out there is a bug in Couplings Designer 1.3 that was introduced with the iOS 7.1 release a couple of weeks ago. The bug introduces a crash whenever one is performing any of the following actions:

- Crashes when synthesizing a new design. A temporary solution is to return back to the newly created design which will now work normally since this bug only appears for newly created designs.

- Crash on design export (via email). Also seems to corrupt the selected design’s data, use this feature with caution.

Please comment below if you are experiencing issues with the app! I will update the software as soon as possible to support iOS 7 better, it will most likely be an iOS 7-only release since Apple has introduced a lot of changes to the SDK since the release of iOS 5 in 2011. The plan is to have these bugs resolved in 1-2 weeks time.

Thank you for your understanding and support, I am sorry for the inconvenience!

Edit (April 10): update 1.4 has been submitted to Apple for approval, which usually takes a week until it ends up in the AppStore. In addition to the bug fixes there are a couple of new features added and a fresh new interface.

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Tutorial, coaxial cavity filter

Read the article: 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.

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Tutorial, combline cavity filter

Read the article: Combline cavity filter.

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.

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New filter synthesis tool for windows

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.

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Tutorial, lumped filters

Read the article: Lumped filter design using coupling matrix techniques.

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.

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Video tutorials available

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.
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Couplings Designer Update 1.2

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

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Couplings Designer Update 1.1

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

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Update 1.1 seed-bug workaround

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!

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