Microwave Power Measurements

The essential requirements for accurate measurement of power at ultra-high frequencies are discussed and some comparisons made with corresponding achievements at low frequency. Attention is drawn to the limitations of well-established microwave techniques and to recent developments in the United Kingdom offering improved methods of dealing with some of the problems and new approaches toward their solution. In particular, consideration is given to recent work in the millimeter waveband by French and Cullen, on an oscillating torque instrument, by Lane, on transverse film bolometers, and by Birch, on a simplified power absorbing wedge with associated temperature sensitive elements mounted in a waveguide. Finally, proposals are made by the author for improved Hall-effect devices and for a novel type of microwave electrostatic wattmeter which should be capable of correct measurements whatever the nature of the load.