A New Precision Low-Level Bolometer Bridge

A low-level RF bridge has been developed for the purpose of calibrating directly the outputs of signal generators over a wide frequency band. Using standard commercial bolometers giving an input resistance of 50 ohms and an error detection scheme based on raidometer techniques, the bridge has a measured sensitivity (S/N=1) of 3.0×10-10 w. The basic bridge design is described in this paper and various applications are discussed. Although designed primarily for RF measurement, the bridge can be applied to the detection of any kind of electromagnetic radiation provided suitable bolometer elements and modulating means can be arranged.