Full-Wave Antenna: Solving the Homework

[Solarmew]

Homework Statement

Homework Equations

see attached image

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?

 

[TSny]

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.