Actually it is a 22 year cycle. It's fairly interesting how it works. The interior of the Sun rotates at a different rate than the exterior so magnetic field lines get twisted in a helix over time and sunspots (magnetic field penetrations on the surface) get forced from the equator to the poles. At the end of a half cycle the magnetic field reverses suddenly and all of the sunspots disappear. Then it starts all over again with the magnetic poles reversed.
Huh? Solar output peaks about every 11 years..... I can get to 22 years if you're placing the solar minima right in the middle, and successive peaks correspond to opposite polarity -- is that about it?
Whoops. The rotation rate is dependent on latitude not depth. Odd, but the sun is a big ball of gas so it doesn't have the structural integrity to force all parts to rotate at the same rate.