[Delta stub design] how to calculate physical dimension of delta stub?

[thaithien]

Hi all,
I have problem with microstrip delta stub design.
I referenced some paper about radial stub, ... but can't find exact program for calculation, even wrote some maltlab m-file for it.But my results are different from others done by some author.

Specially, in the paper "A NEW KIND OF RADIAL STUB AND SCME APPLICATIONS"-attached below, Coimbra wrote a program for delta stub calculation in Basic -Tektronix 4054 .I don't know -Tektronix 4054 programming but maybe I understand the algorithm, so I wrote Matlab m-file but it exist some unknown formular, constant....cause of quality of scanned paper.

Some thread in this forum has mentioned something like that but not clear.
So, let's discuss and find out the answer.

Thanks for your attention!

 

[tony_lth]

The paper decribe old technologies. Now you can use HFSS OR ADS OR AWR to setup the delta stub and can get very good results.

 

[thaithien]

Thanks tony_lth . That means : tuning some parameter to obtain good result ?
I tried it with Tuning tool in ADS.But , it will be better if we have general formula for our design.
It also help our tuning faster.

 

[volker_muehlhaus]

Now you can use HFSS OR ADS OR AWR to setup the delta stub and can get very good results.

Do you mean radial stub or delta stub?
I have not seen delta stub in ADS or AWR so far.

 

[thaithien]

In ADS , it has radial stub and taper.So , you can create a triangle stub(delta stub) from a taper.

 

[volker_muehlhaus]

In ADS , it has radial stub and taper.So , you can create a triangle stub(delta stub) from a taper.

If you do that, the layout will look ok but results will be inaccurate. The electrical model behind the taper is kind of transmission line and not appropriate for describing the triangle stub.

Even the normal radial stub models are not very accurate. Using a taper model makes it worse.