1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Antenna, transmission line

  1. Sep 8, 2004 #1
    Hi,

    I want to clarify some notiona in an antenna. The major components of an antenna are a generator, transmission line and an antenna (dipole). Let's say the whole system has a perfect matche, i.e. the dipole is about 70 ohms as the transmission line. If my generator ,the output voltage, is an impulse which has a duration in a micro second ( let's say 1 micro sec). So, the frequency of this generator is 1 Mhz? If the impluse is a square, the main fundamental frequency is 1 MHz and also , with others harmonics, I means if I do the Fourier Transformation am I right?

    Thanks,

    Mica
     
  2. jcsd
  3. Sep 8, 2004 #2

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    A square wave is composed of odd integer harmonics. The third, fifth, seventh, and higher order odd harmonics all have power in them.

    - Warren
     
  4. Sep 8, 2004 #3
    How can I determined these odd integer harmonics ? and if is another wave form ? And the calculation of the power of these harmonics ?

    Thanks,

    Mica
     
    Last edited: Sep 8, 2004
  5. Sep 8, 2004 #4

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    http://mathworld.wolfram.com/FourierSeriesSquareWave.html

    Look at equation 6.

    The third harmonic has a frequency three times that of fundamental, and has an amplitude one-third that of the fundamental. The fifth harmonic has a frequency five times that of the fundamental and an amplitude one-fifth that of the fundamental.

    - Warren
     
  6. Sep 9, 2004 #5
    Thanks for the information. So, for my dipole radited efficiently, I just match the right frequency output of the generator ? I mean like if my dipole resonances at 1 GHz so, my impluse (voltage source) duration will be 1/1 GHz ( 1 nano second) independent of the wave form?

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

Have something to add?