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Impedance matching on Rf PCB

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enemra

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I have two questions in the image that I have attached. the image is of a power amplifier board.
  1. The output of the amplifier has irregular copper trace with different length until the output SMA, which I pointed as (1). Doesn't this impact the impedance of the trace?
  2. What is the use of two vertical traces before the output SMA, which I pointed as (2)?
enter image description here
Thank you
 
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1. Stepped quarter wave transmission line for impedance matching
2. Transmission line stop filter for (probably 2nd) harmonic suppression
 
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Should be a matching network, from the moment that in the datasheet is mentioned that the output impedance of BLF2425 is about 2.5ohms at 2450MHz.
 
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Thanks to all who answered. Amazing.... Learning on RF part is never ending :( Thanks for the heads up.
 
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The section (1) is a matching network, his function is to present to the transistor some specific impedances (trade-off between efficiency and power output) in the band of interest.
The wide lines are near to the trans are low impedance, by stacking them together a transformer is created. Usualy this kind of network can be quarter wave sections / exponentiel tapper / or even Klopfeinstein taper (non linear step).

The section (2) is with no doubt a low-pass filter as an harmonic filter . The central freq of BLF2425 is 2.4GHz and according to the length of the stubs are tuned @ around 4.8GHz see attached a 10s quick EM simul.
 

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navet said:
The section (1) is a matching network, his function is to present to the transistor some specific impedances (trade-off between efficiency and power output) in the band of interest.
The wide lines are near to the trans are low impedance, by stacking them together a transformer is created. Usualy this kind of network can be quarter wave sections / exponentiel tapper / or even Klopfeinstein taper (non linear step).

The section (2) is with no doubt a low-pass filter as an harmonic filter . The central freq of BLF2425 is 2.4GHz and according to the length of the stubs are tuned @ around 4.8GHz see attached a 10s quick EM simul.
Click to expand...
From which software is this screenshot taken? I am looking for software that can be used to create stubs like this
 
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