  Mapping the polarization of the Cosmic Microwave Background is yielding
exciting data on the origin of the universe, the reionization of the universe,
and the growth of cosmic structure. Kilopixel arrays represent the current
state of the art, but advances in detector technology are needed to enable the
larger detector arrays needed for future measurements. Here we present a design
for single-band dual-polarization Kinetic Inductance Detectors (KIDs) at 20%
bandwidths centered at 145, 220, and 280 GHz. The detection and readout system
is nearly identical to the successful photon-noise-limited aluminum
Lumped-Element KIDs that have been recently built and tested by some of the
authors. Fabricating large focal plane arrays of the feed horns and
quarter-wave backshorts requires only conventional precision machining. Since
the detectors and readout lines consist only of a single patterned aluminum
layer on a SOI wafer, arrays of the detectors can be built commercially or at a
standard university cleanroom.
