1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Full-wave antenna

  1. May 27, 2013 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations
    see attached image

    3. The attempt at a solution
    I'm not sure where to begin with this one. We did a similar problem with a half-wave antenna, where I=I_0 cos(2πz/λ) and it was centered at the origin, so cos = 1 when z = 0.
    So here I figured if we place the antenna in the positive z, then sin will = 0 when z = 0, then max out half way and decrease back to 0. But i'm not really sure.

    Could someone please nudge me in the right direction?
  2. jcsd
  3. May 28, 2013 #2


    User Avatar
    Homework Helper
    Gold Member
    2017 Award

    If you know the field of a single half-wave antenna, then you just need to add the fields from the two half-wave antennas that make up the full-wave antenna. You will need to take into account that the two currents in the half-wave antennas are out of phase and there is an additional phase shift due to the path difference from the antennas to the far-field observation point (like the path difference in a double-slit apparatus). Phasors are a good tool for adding the two fields.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted