Planar Polarimetry Receivers for Large Imaging Arrays at Q-band

The characterization of the intensity fluctuations of the cosmic microwave background (CMB) will be followed by the mapping of the polarization fluctuations of the CMB. Measurement of the polarization fluctuations requires highly sensitive instruments that are only possible by increasing the number of receivers. We are developing a large receiver array for the Q, U imaging experiment (QUIET) by building individual receivers that have noise temperatures close to the physical limit and that are simple, and low cost to build and operate. We developed these planar polarimetry receivers for Q-band by designing InP MMIC amplifiers with noise below 20 K, low loss and highly balanced phase switches and an entirely planar hybrid thin film circuit for the detection of the Stokes parameters Q and U. Our receivers achieve 25 K noise temperature over 8 GHz bandwidth and provide the I, Q and U parameters simultaneously. These planar modules have a simple plug in architecture that enables automated production of a large number of receivers and simple integration of large arrays of receivers