RE: Microwave Optics Experiments

[brian whatcott <inet@intellisys.net>]

At 20:51 10/31/97 -0500, you wrote:
> I see why you are concerned. There is a possibility you are
> dealing with a 10 GHz source....
> But I think you are dealing with standing waves from a reflector,
> so you might well accentuate the positive, and shine your source 
> onto an aluminum sheet reflector.
>
> Along with the michelson configuration that I described in the original
post on this subject, I have also used a standing wave technique to
determine the wavelength.  I simply arrage the transmitter for normal
incidence on a aluminum sheet(as you mentioned) and moved the horn receiver
along a parallel line shifted about 10 cm to one side.  Again I used the
motion detector to directly obtain a plot of received power versus position
and the observed standing wave had the same 1.0 to 1.5 cm  measure as what
was found using the michelson.  

This is conclusive evidence of antinodes at half lambda = 1.5cm.
3 centimeter is the usual way of referring to 10 GHz signals.
 
> I will try the double slit or grating. (However earlier attempts of
demonstrating this while I was trying to demonstrate acoustic interference
failed miserably. The only good source for producing two-source, low
frequency, interference that I found was to run two high impedence
piezo-electric speakers at about 20 kHz and use a microphone as a detector.
>
I thought that 2 slot interference was easy to demonstrate with a lamp 
and a water-wave tray. And a two-prong tuning fork has a natural 
interference pattern.
(But there again, everything is 'easy' to a person who does not have to do
it!)

> Anyway, if you think of anything else, or know of something that
frequently thwarts the observation of double slit interference with
microwaves that I might have overlooked, let me know.
> Brian Oliver

Referring to an Atlas of Optical Transforms (Harburn, Taylor,Welberry. G.Bell
(Plate 10-2)
I see that an array of three circular holes in a horizontal row has a 2-D
Fourier transform of five vertical bars disposed within a large circular
aperture.

I'm not sure about the effective aperture of your detector, but the pattern 
evidently needs to be spaced wider than this dimension, which implies that 
the holes forming the "slits" need to be relatively close...

Regards
Brian
(P.S. Your post was trailing this attachment - Microsoft strikes again, I
guess?)

> Attachment Converted: "c:\intell\eudora\attach\REMicrow"
brian whatcott <inet@intellisys.net>
Altus OK