Patent ID: 7701143

Claim:
A light source comprising: a waveguide body comprising material having an effective dielectric constant greater than 2; the waveguide body configured to have a fundamental resonant mode when power is coupled to the waveguide body at a first frequency in the range of about 600 MHz to 2.3 GHz; a bulb positioned adjacent to the waveguide body; the bulb containing a fill that forms a light emitting plasma when the power is coupled to the bulb from the waveguide body; a central axis defined through the center of the bulb in the direction that light is emitted from the bulb away from the waveguide body; and a cross section of the waveguide body orthogonal to the central axis and having a maximum distance between any two points on the cross section; wherein a ratio of the maximum distance between any two points on the cross section, divided by the wavelength of the power at the first frequency in the material having the effective dielectric constant, is less than 0.75.