How a Ground Plane Reduces PCB Noise

[hioyo]

Dear Team,

Can you please tell me how ground plane works.I know it provides a leat impedance path for return currents.
But How a Ground Plane Reduces PCB Noise.

regards
Haio

 

[KlausST]

Hi,

* as a plane it shields electric fields.
So that the noise of a trace can not go "through" the plane to the opposite side.

* magnetic field / impedance
It´s not the retunr path alone, it´s the combination with the signal path.
A signal in a trace causes a current and thus a magnetic field. Causing an inductance.
With a GND plane, the "return" current flows in the GND plane in very close proximity to the signal.
The current direction in the GND plane is opposite to the signal current. And so are the magnetic fields, thus thy cancel out each other. No magnetic field, no inductance, no transmitting antenna for EMI

Klaus

added:
This is an often discussed topic, thus there are many hits on an internet search. Besides a lot of good documentation you will also find videos with explanation and according simulations.

 

[hioyo]

Hi,

* as a plane it shields electric fields.
So that the noise of a trace can not go "through" the plane to the opposite side.

* magnetic field / impedance
It´s not the retunr path alone, it´s the combination with the signal path.
A signal in a trace causes a current and thus a magnetic field. Causing an inductance.
With a GND plane, the "return" current flows in the GND plane in very close proximity to the signal.
The current direction in the GND plane is opposite to the signal current. And so are the magnetic fields, thus thy cancel out each other. No magnetic field, no inductance, no transmitting antenna for EMI

Klaus

added:
This is an often discussed topic, thus there are many hits on an internet search. Besides a lot of good documentation you will also find videos with explanation and according simulations.

This is a very good explanation.Before posting I did a google search.I did not see any beautiful explanation like this.