measurement of the Cosmic Microwave Background polarization

rays to measure the polarization of the cosmic microwave background. 217 GHz prototype pixels have previously been characterized and showed promising per-formance1. Our design uses a double slot dipole antenna and an integrated mi-crostrip band defining filter. New devices have been tested which include on-chip test structures to improve our understanding of detector performance and guide future development. In parallel with this, large arrays of bolometers based on the prototype pixel design have also been constructed. The array pixels are a hetero-geneous mixture of single band pixels at 90 GHz, 150 GHz, and 220 GHz and now incorporate dual-polarization antennas2. Preliminary results from optical testing of array pixels are presented. These bolometer arrays will be used in the upcoming CMB polarization experiment POLARBEAR. PACS numbers: 85.25.Pb, 07.57.Kp,85.60.Gz