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Series stubs using microstrip or stripline.

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yungman

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how to make stripline

How can I design a matching circuit using microstrip series stub on a PCB?

I have been looking around and never understand what is a series stub. I understand design using smith chart, I just don't get the physical structure using stripline or microstrip.

Thanks
 

stripline stubs

Don't try to use a series stub matching network when working with microstrips. It is much easier to implement using shunt stubs instead. Physically it is just a piece of microstrip conductor at a 90° angle to the microstrip line.
 

series stub microstrip

As YoungEng said is better shunt stub .
Working frequency ?
Bandwith ?
Sustrate type ?
 

microwave stripline stub

Simple series stubs are not possible in microstrip or stripline, as you can make a series structure in the top trace, but not in the ground plane underneath.

Never the less, there are a number of series-like structures that can be used in stripline/microstrip. With some creativity, these can be included in matching structures. Look at Microwave Filters Impedance-Matching Networks, and Coupling Structures by Matthaei, Young, and Jones. On pages 219-228 there are a lot of depictions of such structures, although the models shown there are only accurate for TEM such as stripline, and not microstrip (which have εeven ≠εodd).

Rich
 
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stub series stripline

You can do a lot with a series stub. With a 90degree phase shift at a given impedance you can transform to nearly any impedance.
Here is a spreadsheet that will show you how to make them:
**broken link removed**

You can use it to make as many sections as you want. It only covers real impedances but you could tune it in your simulator for a complex match.[/url]

The formula for a single 90 degree line is simple and as follows:
ZT=(ZL*ZS)^0.5
 

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