Radio-frequency impedance measurements

Article By:

Callegaro, Luca Electromagnetism Division, Istituto Nazionale di Ricerca Metrologica, Torino, Italy.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.567870

The measurements of electrical impedance at frequencies ranging from a few tens of kilohertz to about 1 GHz. This broad radio-frequency (RF) range encompasses frequencies from the extralow-frequency band to the very-high-frequency (VHF) and ultrahigh-frequency (UHF) bands. At such frequencies, an electromagnetic field can radiate from the device under measurement and interact with the environment and the measurement setup itself, thus affecting the reading. To avoid such effects an accurate measurand definition, stating precisely how voltage and current have to be measured, is of primary importance. The effects of measurement cables and connection fixtures must also be taken into account. Several measurement methods are employed at radio frequencies, which can be grouped loosely as I–V methods, resonance methods, bridges, and network analysis. See also: Electrical impedance; Radio-wave propagation

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