Absolute calibration of a class of torque-operated microwave wattmeters incorporating resistive elements

A general method of calibration suitable for loss-free (or low-loss) torque-operated microwave wattmeters has been developed by the author in a previous paper. The present paper describes an extension of that theory to cover the case of a wattmeter of which a component part is a lossy element in which a fraction of the power to be measured is dissipated. To apply the method, it is necessary that the lossy element be detachable, so that it can be replaced by a movable short-circuit. An example of such an instrument is the microwave analogue of the electrostatic wattmeter, recently proposed by Barlow. The new method of calibration was developed with particular reference to that instrument, though it is capable of somewhat wider application.