Balanced Receiver Technology Development for the Caltech Submillimeter Observatory
The Caltech Submillimeter Observatory (CSO) is located on top of Mauna Kea, Hawaii, at an altitude of 4.2 km. The existing suite of facility heterodyne receivers covering the submillimeter band is rapidly aging and in need of replacement. To facilitate deep integrations and automated spectral line surveys, a family of remote programmable, synthesized, dual-frequency balanced receivers covering the astronomical important 180-720 GHz atmospheric windows is in an advanced stage of development. Installation of the first set of receivers is expected in the spring of 2012. Dual-frequency observation will be an important mode of operation offered by the new facility instrumentation. Two band observations are accomplished by separating the H and V polarizations of the incoming signal and routing them via folded optics to the appropriate polarization sensitive balanced mixer. Scientifically this observation mode facilitates pointing for the higher receiver band under mediocre weather conditions and a doubling of scientific throughput (2x4 GHz) under good weather conditions.
© 2011 IEEE. Manuscript received September 06, 2011; revised November 06, 2011; accepted November 19, 2011. Date of publication December 19, 2011; date of current version January 18, 2012. This work was supported in part by NSF Grant AST-0838261. The authors would like to thank M. Gould of Zen Machine and Scientific Instruments for his mechanical advice and machining expertise, J. Pierson of the Jet Propulsion Laboratory for his assistance with the medium power amplifiers modules, J. Parker for assembly of the many LO related components, K. Cooper for setting up the data acquisition network, and J. Groseth for help with the Cryogenics and laboratory work. We also wish to thank Pat Nelson for rewiring of the Cryostat and the CSO day-crew for their logistic support over the years. They would also like to thank Prof. J. Zmuidzinas of Caltech and the former CASIMIR program for providing the K_α -band synthesizers and Fast Fourier Transform Spectrometers (FFTS).