Proposed high-accuracy superconducting power meter for millimeter waves

A prototype bolometer is described which offers potential as a nearly ideal power meter by absorbing and measuring nearly all of the incident power. The load developed for this bolometer is shown to reflect no more than 0.01% of the incident power. Assuming that the losses in niobium are no greater than those in lead, the power absorbed by the bolometer but not measured is less than 0.02% over a significant fraction of the WR-22 band (33-50 GHz). If the DC substitution error can be reduced to a comparable level, the proposed bolometer offers a possibility of improving the accuracy of millimeter-wave power measurement by an order of magnitude.<>