The ceramic antennas are generally dielectric antennas, not the conducting antennas we all know and love. I am not a RF wizard, but I can take a shot at explaining the differences as I understand them (comments/corrections welcome!).
As I understand it, there are two basic types of ceramic antenna, but both kinds can be combined in one structure.
The first type is basically a standard conducting antenna using metal conductors on ceramic with a very high dielectric constant. The dielectric pretty much contains the near field, which greatly reduces the user's hand detuning the circuit. It also makes it a lot easier to put multiple antennas close together and allows for a smaller antenna (IIRC, wavelength is proportional to the square root of the dielectric constant).
In the second type - often called a dielectric resonator antenna - the dielectric resonates and becomes a source of radiation. This mode can be combined with the mode above, and parasitic elements can be added to make absolutely sure that old-school engineers such as myself can't figure out what is going on without going back to school. :)
In addition, the dialectic can act as a lens. For an interesting discussion on how this works with grapes in a microwave, see [ http://128.252.223.112/posts/archives/dec97/882909591.Ph.r.html ]. also see [
All of which pretty much explains why I would hire someone who knows what he is doing rather than attempt such a design myself. This stuff is a Black Art.