Eleanor M. Livingston and Robert T. Adair

Abstract:

Measurement techniques are described for the evaluation of electrical performance of commercially available radiofrequency (rf), microwave (mw) and millimeter wave (mmw) power meters which use bolometric power sensors and typically operate from 10 MHz to 26.5 GHz for an average of 10 W to 10 mW with appropriate attenuation for higher power ranges.

Power measurements at dc and low frequencies are relatively straightforward since voltage, current, and impedance are discrete entities from which values of power may be calculated through use of Ohm's law. For radio, microwave and millimeter wave frequencies, however, these became, complex, interactive, distributed parameters. Impedance mismatch, leakage, and nonlinear responses must also be considered. The principle of the bolometric method of measurement of rf, mw, and mmw power is presented.

Techniques are described for analysis of: ranges of frequency and power, operating temperature, stability, response time, calibration factor, extended power measurement, overload protection, and characteristics of the internal power reference source. Some automated methods are discussed. Block diagrams of test setups are presented.

Sources of uncertainty in the bolometric method are analyzed.

Keywords: millimeter wave; microwave; calibration; Testing; RF sensor

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

For questions or information on this or any other NTIA scientific publication, contact the ITS Publications Office at ITSinfo@ntia.gov or 303-497-3572.

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