High dynamic range 140-220 GHz radiometer using dual-channel superheterodyne receivers

摘要

A millimetre-wave radiometer in the range 140-220 GHz using dual-channel superheterodyne receivers is described. The dynamic range of the radiometer is estimated to be 163 dB. The linearity of the receiver is traceable to a low-frequency voltage ratio standard. A 10-120 dB synthesised rotary vane attenuator has been measured with uncertainties of 0.022-0.90 dB at 220 GHz to verify the accuracy of the radiometer.