Investigation into the behavior of microwaves

[3432401GSPT]

Hi,

For an assignment at school I am looking into the behaviors of microwave propagation. For instance I have familiarized myself with Fraunhoffer diffraction (Single slit, Double slit and grating) and an amount of wave mechanics in general.

What I would like to do however is to link all this very 'nice' theoretical behavior of waves, to a real life situation. The real life situation that I originally began with was microwave propagation in the household. Approx 2.4ghz from microwave oven, Wifi, cordless phones etc. I can investigate all sorts of things like the drop-off of intensity with the square of distance but I'm struggling to find an area I can investigate that unifies what you would learn in a beginners physics textbook, and the seemingly chaotic EM behavior in the real world, for instance the interference at said wavelength.

I was thinking that I could describe microwave propagation in the environment (diffraction, reflection, etc.) and almost make a 'radar' to find given shapes etc. using a microwave source situated at one end, and then a microwave detector at the other to find interference patterns.
What materials would give fairly consistent and predictable behavior/interaction with microwaves?
Are there any other technologies that I could look into/be of interest other than a simple box source and a horn receiver?

Thanks for any help/suggestions :) :)

 

[berkeman]

Hi,

For an assignment at school I am looking into the behaviors of microwave propagation. For instance I have familiarized myself with Fraunhoffer diffraction (Single slit, Double slit and grating) and an amount of wave mechanics in general.

What I would like to do however is to link all this very 'nice' theoretical behavior of waves, to a real life situation. The real life situation that I originally began with was microwave propagation in the household. Approx 2.4ghz from microwave oven, Wifi, cordless phones etc. I can investigate all sorts of things like the drop-off of intensity with the square of distance but I'm struggling to find an area I can investigate that unifies what you would learn in a beginners physics textbook, and the seemingly chaotic EM behavior in the real world, for instance the interference at said wavelength.

I was thinking that I could describe microwave propagation in the environment (diffraction, reflection, etc.) and almost make a 'radar' to find given shapes etc. using a microwave source situated at one end, and then a microwave detector at the other to find interference patterns.
What materials would give fairly consistent and predictable behavior/interaction with microwaves?
Are there any other technologies that I could look into/be of interest other than a simple box source and a horn receiver?

Thanks for any help/suggestions :) :)

Welcome to the PF. :-)

I'd be careful about trying to make your own transmitter -- even though the 2.4GHz band does not require a license to transmit in, it is much better to use a pre-made and pre-qualified transmitter. Making your own could result in out-of-band interference with other receivers, and a visit from the FCC.

One of the ways we have characterized 2.4GHz devices and their signal propagation was to take advantage of the (usually) built-in Receive Signal Strength Indicator (RSSI) circuit in a receive device, and move the device in a horizontal x-y pattern to find the multipath nulls. The nulls you get from multipath reflections and other issues can be pretty dramatic.

You may be able to find some sort of "sniffer" device that can receive over the full 2.4GHz "ISM/microwave oven" band, and see what kind of interference exists in different environments.