Matching transmission lines with parasitic strips

[tyassin]

Hello,

In the attached picture is shown some matching for a power amplifier, where there are a number of parasitic strips.

What is the purpose of these?

Thank you

 

[volker_muehlhaus]

The purpose of the patches is to allow tuning of the impedance matching (add capacitance/make lines wider). In the beginning, the patches are isolated and have no effect. For tuning, you can now add them one after another by soldering.

Sometimes, you see these tuning patches all connected with one narrow trace. In that case, then tuning is possible by cutting these narrow traces to remove the patches one after another (reduce capacitance/make lines narrower).

Best regards
Volker