# impedance matching methods | ADS matching tool

1. ## impedance matching methods | ADS matching tool

Hi guys,

I'm a trainee at a research institution, I'm working on RF design and the goal is to design amplifier, so in RF design there are EDA tools, we are using ADS Advance design system, one of the phases in my trainee program is about match impedance between a source and the load, I started to look at how to match impedances, and find out there are several methods: transformer,λ by 4, L-network, pi-network and T-network.

Question#1: When I'm using ADS there are auto-generate matching networks but I'm confused how it's work, there is different options low/high/bandpass matching network, are they related to L/pi/T network? or they are a different methods?

The circuit I'm trying to match and my tries in ADS and manual calculation and couldn't reach desirable output

Question#2: how did he make the design the matching network on the first page?

My adviser is busy so he gave me slides to a workshop happen last year and the circuit I'm trying to match was exercise there. so my training is self-learning, I'm supposed to learn RF circuit, ADS, and finally, design amplifier doing some function which I'm still don't know xD

Question#3: To reach my trainee goal designing an amplifier in RF, can you recommended me slides/videos/course in amplifiers

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2. ## Re: impedance matching methods | ADS matching tool

I neither understand the proceeding in the document. Obviously the simple matching network at page 6 fulfills the requirements (|S11| < -9 dB) while page 1 doesn't.

200 MHz matching circuit bandwidth may require a more complex circuit than single CLC pi network if higher performance is intended, but page 1 design doesn't look like a useful approach.

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3. ## Re: impedance matching methods | ADS matching tool

Let me apologize to not write the topic clearly, thanks for clarifying my doubts in my tries :)

Can you explain how to deal with non-pure source in matching impedances or provide an example? Can you answer other questions in post#1?

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4. ## Re: impedance matching methods | ADS matching tool

The most simple solution to the exercise problem (match 220 ohm || 0.877 pf to 50 ohm in 1.2 to 1.8 GHz band) is a single series inductor of about 9.6 nH. You find it by applying Smith Chart method at the center frequency and I guess it's the expected solution.

I suggest to review a RF text book, e.g. Pozar RF Engineering, chapter impedance matching and tuning.

Selection of matching network topology and transmission line versus lumped circuit depends on the application, performance parameters and available technology and can't be answered generally.

E.g. for RF transmitters, you mostly choose low-pass topology for maximal harmonic suppression.

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