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impedance of the PCB balanced line of a balun with a complex impedance

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gmarocco

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I am using the balun DEA202450BT-7077A1 which has a balanced port differential impedance of 34+j72 Ohm. In theory in order to avoid reflections the impedance of the lines connecting the balun should be 34+j72 Ohm. But in practice which is a reasonable value for the impedance of the lines? The balun is connected to the bluetooth chipset BC63B239A04-IYB-E4.
Thanks in advance
 

Although it's possible to perform the matching with line segments only, you'll most likely want a lumped element matching network due to room constraints.
 

As already stated above, tune out the imaginary part at the balun.
You can cancel the imaginary part with a 2.2pF series capacitor, to obtain 34 +j0 ohm input impedance.
 

Or use parallel + series C to match any real impedance between 34 and 186 ohm.
 

This is only theoretical values at BT frequencies. For the real application add corrections for PCB traces impedances, phase delay due to trace lengths, non ideal components and an antenna that only partly is close to 50 Ohm.
My general advise is to leave space for a matching network but wait to decide matching components values until whole Bluetooth unit including its normal environment can be measured with a VNA.
If you anyhow want to see theoretical matching results for a L-network:
 
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