Electronics > Beginners
Replace trace impedance with resistor?
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FriedMule:
I have fount out that a 50 Ohm impedance trace on a PCB is a hard (and expensive) thing to do when we talk about 0Hz-1GHz. Is it possible to use a SMD 50 Ohm resistor instead?
tszaboo:
Sure. You can also replace an antenna with a 50 ohm resistor, it looks perfect on the VNA. And a coax cable can also be replaced with just a resistor on one end and then regular cable. I dont even know why people spend so much time designing these things, it is so simple.
FriedMule:

--- Quote from: blueskull on August 30, 2019, 05:49:45 pm ---
--- Quote from: NANDBlog on August 30, 2019, 05:43:49 pm ---Sure. You can also replace an antenna with a 50 ohm resistor, it looks perfect on the VNA. And a coax cable can also be replaced with just a resistor on one end and then regular cable. I dont even know why people spend so much time designing these things, it is so simple.

--- End quote ---

Be aware that this is the beginner's section. Your sarcasm may lead the OP to the wrong direction.

--- End quote ---
Yes and sarcasm is hard to read from his text, not much to hint sarcasm from:-)
FriedMule:
Maybe I should refrace my question, is there any way to cut down on the price (cheap PCB producer) or a way to at least sort of "guarantee" that I hit 50 Ohms impedance in first try?

I have tried to use https://www.eeweb.com/tools/microstrip-impedance to calculate the impedance
Expect to use a Rogers type PCB
magic:
Even if you build a proper transmission line, it needs to be terminated with 50Ω to ground at the receiving end anyway, unless the load has built-in termination or it's some external RF connector.

Supposedly you may get away with wrong line impedance if the distance is some 10x shorter than the wavelength. But wavelength at 1GHz is merely 20~30cm so that doesn't buy you much. Even is such case, make it a proper transmission line, with a nice ground return conductor running in parallel at uniform distance.
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