Germanium Bolometer Detector of Millimeter Wavelength Thermal Energy

Abstract

This paper describes the construction and evaluation of a Ka band bolometer receiver using a highly temperature-resistance dependent (at 4.2°K) doped germanium bolometer of Texas Instruments, Inc. The receiver noise equivalent power (NEP) of approximately 10−9 W and input bandwidth exceeding 12 Gc has a rms signal level indicating uncertainty equivalent to 90 C° per cycle of output filtering. Evaluation of the germanium bolometer as a millimeter wavelength radiometer detector was performed at Ka band to utilize existing apparatus and to facilitate fabrication of the receiver. With the increased sensitivity anticipated for smaller bolometer elements, short millimeter and submillimeter wavelength scaled models of the receiver appear promising as detectors for radio telescopes.