Sinuous-Antenna coupled TES bolometers for Cosmic Microwave Background Polarimetry

We are developing antenna-coupled TES bolometers for CMB polarimetry that receive both linear polarizations over nearly two octaves of bandwidth. This ultra-wide bandwidth is achieved with a novel adaptation of the sinuous antenna that integrates microstrip feed-lines onto the arms of the antenna and uses a contacting extended hemispherical lens to focus the beam. It is challenging to achieve desirable antenna performance over such a wide band and our version of the sinuous antenna offers a unique solution. We have integrated this antenna with TES-bolometers and report on a series of optical tests that demonstrate the antenna beams's high symmetry, cross-polarization rejection, gain, and optical efficiency over the operating band.