Abstract :
Methods requiring only measurements of impedance are used to investigate the efficiency of resistance-type milliwattmeters at frequencies of 9.2 Gc/s and 3 Gc/s (wavelengths of 3.26cm and 10.0cm). For fine-wire bolometers the results agree with those obtained by calorimetric methods and are consistent with the few results previously available at lower frequencies. Accurate values of efficiency cannot be obtained by impedance methods, in their present form, for thermistors at microwave frequencies owing to the uncertainty regarding the precise impedance of the semi-conducting bead.
