Electromagnetic wave propagation when blocked by metal

[vincenttswong]

Dear all,
I am a newbie in electromagnetic wave. Can you educate me, what will happen when an electromagnetic wave is blocked by a piece of flat metal placed in front of it?

My intention is to build a thermal chuck using peltier for to measure femto amps from my device.
I am worried if EMF created from peltier will affect my measurement.

Below is my stack(top-down):
Device under test -> Metal plate(for conductivity) -> ceramic ->metal plate(connect to ground) -> Peltier -> Heatsink

Please feel free to comment if there is any potential problems.

Look forward to hearing suggestion from you.

Thank you


Regards,
Vincent

 

[mfb]

If the frequency is not too high (below visible light should be fine) or too low (with a wavelength larger than the device), the metallic surface will absorb some small fraction and reflect most of the intensity.

 

[vincenttswong]

mfb,
Thank you for your prompt reply. Instead of PWM, I am using a steady current source. Therefore frequency is not high.
You did mention about absorbance of small fraction of EM wave by the metal plate. Will the absorbed EM by metal plate(connect to ground) be 'drained' to ground? Am I overdoing it by connecting this plate to a clean ground?

Look forward to hearing from you.

Thank you

Regards,
Vincent

 

[mfb]

I don't see where you expect electromagnetic waves at all. Constant, direct current does not lead to the emission of electromagnetic waves.

 

[vincenttswong]

mfb,
Thanks for your prompt response. I was out of town last week and has got no internet access.
Last question I have here:
Will the sanwiched metal-dielectric-metal layer caused capacitive noise? If yes, is there any ways that I can eliminate them? Can I simply ground all metal plates to drain the charges?

Look forward to hearing from you.

Thank you


Regards,
Vincent

 

[mfb]

I think that will depend on details of the setup. Grounding metal plates makes them immune to low frequencies, but you can still have some HF-noise.
I don't know which kind of noise your peltier element generates.