Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Microwave beam width

  1. Aug 27, 2014 #1
    I guess we all know laser beams. I wonder if we can make beams in the microwave frequency range and how the beam width relates to the frequency, e.g what is the minimum beam width we can achieve with a frequeny of 50Ghz.
     
  2. jcsd
  3. Aug 27, 2014 #2

    davenn

    User Avatar
    Science Advisor
    Gold Member

  4. Aug 29, 2014 #3
    I can see beam width is expressed in degrees of an angle and not in units of length. So beams have cone shape and not cylindrical shape afterall? Or (I believe thats the case) is it that they have no shape at all, we just "make up" their shape by considering cutoff values in the power of the field?
     
  5. Aug 29, 2014 #4

    davenn

    User Avatar
    Science Advisor
    Gold Member

    yes that's correct. Even a well colluminated laser beam will spread out over a distance
    a radio signal even more so

    a radio signal beamwidth is usually given ( as you saw) in degrees and to its -3dB ( half power) points either side of the beam centreline. Beamwidth is very dependant on frequency and antenna gain
    My 24GHz signal from a 1 metre diameter dish has a -3dB beamwidth of about 4 degrees ( ~ 2 deg either side of the centreline)


    Dave
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Microwave beam width
  1. Metal in a microwave (Replies: 0)

Loading...