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Microstrip impedance matching

goatmxj666

Member level 2
Hello,

I made RF power amplifier as IC including matching networks (input, output).

Now, I have to make PCB board for testing.

I wondering how do I design microstip line for my chip.

Should the microstrip line match between source 50 ohm and chip's input impedance?

The output matching network is already matched with 50 ohm.
If so, could I just design the microstrip line to be short and thick without matching the output impedance of the chip to 50 ohm?

Solution
To be precise, the input side LCs (L1-C1 and L2-C2) are not impedance matched, but matched to the resonant frequency only.
I interpret this statement as meaning the input reactance at a particular frequency is zero, but the resistance is not 50 ohms, but - for example - 10 ohms.

In this case, yes -- you can use a quarter-wave transformer, e.g., a microstrip with impedance of 35 ohms -- to match the input impedance (at a particular frequency).
If the IC includes the matching network, then the input impedance is already 50 ohms (or whatever you designed it to be). In this case, yes, you can just feed it with a TL directly.

To be precise, the input side LCs (L1-C1 and L2-C2) are not impedance matched, but matched to the resonant frequency only.

Is the matching between the source's 50 ohms and the PA's input impedance done with a microstrip line?

Or should I draw a microstrip line, which has 50 ohm impedance?

To be precise, the input side LCs (L1-C1 and L2-C2) are not impedance matched, but matched to the resonant frequency only.
I interpret this statement as meaning the input reactance at a particular frequency is zero, but the resistance is not 50 ohms, but - for example - 10 ohms.

In this case, yes -- you can use a quarter-wave transformer, e.g., a microstrip with impedance of 35 ohms -- to match the input impedance (at a particular frequency).

I interpret this statement as meaning the input reactance at a particular frequency is zero, but the resistance is not 50 ohms, but - for example - 10 ohms.

In this case, yes -- you can use a quarter-wave transformer, e.g., a microstrip with impedance of 35 ohms -- to match the input impedance (at a particular frequency).