Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Help me with building microwave pinhole camera

Status
Not open for further replies.

g86

Full Member level 4
Joined
Jan 21, 2003
Messages
212
Helped
11
Reputation
22
Reaction score
7
Trophy points
1,298
Location
On top of antenna :))
Activity points
2,232
Microwave Camera

I am going to make a microwave camera. just like optical one. no tracing or tracking. Microwave pinhole camera. Who can help me to select:

1. A box
2. Pin Hole
3. Photographic plate
4. Focusing lense


First of all I want to know what will be my output picture??

Who can help...

:!: :idea: :?:
 

flatulent

Advanced Member level 5
Joined
Jul 19, 2002
Messages
4,629
Helped
489
Reputation
980
Reaction score
150
Trophy points
1,343
Location
Middle Earth
Activity points
46,689
two aspects

There are two aspects to this problem. Both involve the 1E4 to 1E5 ratio of the wavelengths.

The physical size should be scaled from a working optical pinhole camera by the above factors. This would reduce the portability.

The other problem is the reduction of a photon energy by the same factor. This is the show stopper (no solution). Finding a detection scheme which would work on such low photon energy is a problem. This is way below the chemical bond energy of photo film and the band gap of semiconductor detectors.

What about using a two dimensional phased array and ordinary microwave amplifier/detector/video amplifier? You could raster scan vertical and horizontal angles and use the detected energy to intensity modulate a display of the television or computer monitor type.
 

g86

Full Member level 4
Joined
Jan 21, 2003
Messages
212
Helped
11
Reputation
22
Reaction score
7
Trophy points
1,298
Location
On top of antenna :))
Activity points
2,232
Re: two aspects

flatulent said:
What about using a two dimensional phased array and ordinary microwave amplifier/detector/video amplifier? You could raster scan vertical and horizontal angles and use the detected energy to intensity modulate a display of the television or computer monitor type.
Just like CCD camera..right?

:!: :idea: :?:
 

flatulent

Advanced Member level 5
Joined
Jul 19, 2002
Messages
4,629
Helped
489
Reputation
980
Reaction score
150
Trophy points
1,343
Location
Middle Earth
Activity points
46,689
not exactly

This is not exactly like a CCD. In that method the light image falls on many locations on the semiconductor and produces photons. In this method all of the antenna elements receive signals and combine them into one amplifier path.

This is sort of like a RADAR set only there is no transmitter. The receiver depends on active emitters. Another way of looking at it is a direction finding system with the parameters horizontal and vertical angle.
 

g86

Full Member level 4
Joined
Jan 21, 2003
Messages
212
Helped
11
Reputation
22
Reaction score
7
Trophy points
1,298
Location
On top of antenna :))
Activity points
2,232
Re: not exactly

Then how to make an image. This is just like a single antenna and without scanning how will it work?

:!: :idea: :?:

flatulent said:
This is not exactly like a CCD. In that method the light image falls on many locations on the semiconductor and produces photons. In this method all of the antenna elements receive signals and combine them into one amplifier path.

This is sort of like a RADAR set only there is no transmitter. The receiver depends on active emitters. Another way of looking at it is a direction finding system with the parameters horizontal and vertical angle.
 

flatulent

Advanced Member level 5
Joined
Jul 19, 2002
Messages
4,629
Helped
489
Reputation
980
Reaction score
150
Trophy points
1,343
Location
Middle Earth
Activity points
46,689
set of numbers

You will get a set of voltages for each vertical and horizontal angle that you scan the antenna. These will have to be turned into visual pixels by electronic display means.

Because of the very large wavelength, you will get very crude images due to the wide beamwidth of any portable sized antenna.
 

crono

Member level 3
Joined
May 1, 2001
Messages
59
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
766
Hi,
If i'm not wrong you are talking about a radiotelescope...
In relation with the beam size of the antenna, wich resolution do you want?
and for wich kind of images?
 

g86

Full Member level 4
Joined
Jan 21, 2003
Messages
212
Helped
11
Reputation
22
Reaction score
7
Trophy points
1,298
Location
On top of antenna :))
Activity points
2,232
Now it is difficult to answer your question because I don't know much about the priciple of working of a radio telescope. I just thought about a pin hole camera.

Now as you know if we want to replace with a microwave camera we have to go for a big pin hole as well as big cavity, though they are dependent on wavelength. Another thing is that we cannot use a camical to take the image. we have to use antenna for receive the image. Flatulent has suggested some way of getting the image by cluster of antenna and sensing the active radiation. I feel we also can use a transmitter antenna which can be use like a flash :)

What do you think? After design and fabrication surely I ll install it at moon as my next project..and focus it on earth..to see the radiating earth and reflector earth..


:!: :idea: :?:

crono said:
Hi,
If i'm not wrong you are talking about a radiotelescope...
In relation with the beam size of the antenna, wich resolution do you want?
and for wich kind of images?
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top