A Wide-Range CW Power Measurement Technique

An accurate power measurement technique is described, which makes possible the determination of the net power delivered to a load of arbitrary impedance over a wide power range. A standard power meter is employed to fix a reference power level. Subsequent measurements consist of dimensionless ratios that can be obtained from precision attenuators. The method is applicable to a very wide range of frequencies and was demonstrated at a frequency of 30 MHz with power measurements extending from 10-2 to 10-14 watt. Maximum uncertainties ranged from ~0.5 to 1.5 percent. This technique is applicable in the measurement of the sensitivity of very-low-level detectors, receivers, radiometers, etc.