Antennas, space beam splitters and receivers for precision radiometers exploring the reionization and recombination epochs

The challenging goal of detecting faint and wideband spectral features arising from cosmological evolution in the thermal state of the baryons has driven recent progress in radiometer technology. Because these faint signals are received with foregrounds and terrestrial RFI that are overwhelmingly larger in power, the design of sensors of the EM field and associated receiver configuration need special care to minimize contaminations into the spectral domain and in particular into the spectral modes where the cosmological signatures reside. We present recent progress at the Raman Research Institute in the design of wideband frequency independent antennas, space beam splitters, and receiver configurations that are designed to self-calibrate spectral structures arising from self-generated receiver noise. All these innovative elements are purpose built for precision radiometers. We present engineering test and measurement results from prototypes as well as results of astronomy measurements of the cosmic radio background from field deployment.