Is it possible to build a catch all electormagnetic wave spectrum generator?

[GreenAce92]

I had "posited" or proposed this idea to a professor of mine about building a device which could capture all forms of electromagnetic radiation with varying sized charged particles and a solution that was conductive.

Another option is a type of electromagnetic fabric which is basically variable sized antennas from nm to meter scale, sort of like expanding exponential curves that are made from conductive wire that capture stray electromagnetic waves.

For the example in the first paragraph (sentence) I thought it could capture everything from xrays, infrared, light etc...

My professor said it wouldn't generate much energy.

What if it was really big! Let's say we converted the salt beds / deserts into these electromagnetic catching generators?

Is it worth investigating?

 

[mfb]

It would not generate any energy, as energy is conserved. You descibe an object known as perfect black body. There are very good approximations to this, but they cannot be used to harvest energy (unless you expose them to sunlight, solarthermal power plants exist) - in thermal equilibrium, they have to radiate away the same amount of energy, this follows from the second law of thermodynamics.