# Rotate in spherical coordinates

1. Nov 11, 2007

### daudaudaudau

Hello !

In electromagnetics, the electric field of a small dipole in a spherical$$(r,\theta,\phi)$$ coordinate system is
$$E(\theta)=A\cdot \frac{e^{-jkr}}{r}\sin(\phi)\hat\phi$$

If the dipole is directed along the z-axis. (I used this geometry: http://mathworld.wolfram.com/SphericalCoordinates.html. Sometimes $$\theta$$ and $$\phi$$ are swapped.)

A is just a constant number.

My question is now: What if I want to know the field of a dipole, which is directed along the y-axis, or any axis? Is it possible to rotate $$E(\theta)$$ to make it point in any direction?

Cheers,
Anders