Calibration of Electromagnetic Field Sensors and Probes, Excluding Antennas, from 9 kHz to 40 GHz
|Publication Date:||9 June 2005|
Consensus calibration methods for electromagnetic (EM) field sensors and probes are provided. Data recording and reporting requirements are given, and a method for determining uncertainty is specified.
This standard provides calibration methods for electromagnetic (EM) field sensors and probes, excluding antennas per se, for the frequency range of 9 kHz to 40 GHz. The original version of this standard was developed and released in 1996 in response to the electromagnetic compatibility (EMC) test and measurement community's need for standard (consensus) methods of calibration for commonly used EM field sensors and probes. This version of the standard provides updates to the original 1996 version to clarify items that some users may have found difficult to understand, to expand details and examples with respect to determining and expressing calibration uncertainty, and to present additional technical background information. Also, this version includes calibration methods for specific field probes used for commercial electronic products radiated immunity testing and H-field probe calibrations applicable to ANSI C63.19 [B1]a testing.
This standard provides calibration methods that are appropriate to various frequency ranges and user requirements. Methods for creating standard electric and magnetic fields used for calibration are presented. Because the specific calibration needs for a particular field probe or sensor depend on its intended use, a method to specify and communicate calibration requirements is provided. This standard also provides details for determining and expressing calibration uncertainty.
This standard provides calibration methods for electromagnetic (EM) field sensors and probes, excluding antennas per se, for the frequency range of 9 kHz to 40 GHz. Field injection probe (i.e., transmitting) calibration is not covered by this standard. This standard is not applicable to electromagnetic interference (EMI) emission measurement antennas, which have sometimes been referred to as probes, such as active and passive rod and loop antennas, generally used in the frequency range of 9 kHz to 30 MHz. Calibration of immersible and implantable probes for specific absorption rate (SAR) testing is not considered in this standard; IEEE Std 1528™-2003 [B57]1 should be consulted for guidance on SAR probe calibrations.
This standard provides various calibration methods that are appropriate to various frequency ranges and various user requirements. These methods are applicable to any (e.g., active, passive, photonic) field sensor or probe. Methods are provided for frequency domain calibration and time domain (i.e., transient) calibration.
Methods for creating standard electric and magnetic fields are described in Clause 5. Each method has calculable field strengths and associated uncertainties. Each standard field method is individually addressed. The field generation information was obtained from IEEE Std 291™-19912 and from IEEE Std C95.3™- 2002, with additional information from sources listed in the bibliography.3 Further information on probe calibration methods and applications guidance for frequencies below 100 kHz is given in IEEE PC95.3.1™ [B53], IEEE Std 1308™-1994 [B54], and IEEE Std 1460™-1996 [B55]. Calibration methods for probes used for electronic-product radiated immunity testing in accordance with IEC 61000-4-3 [B49] are described in Annex D. Calibration methods for probes used for testing near-fields of mobile telephones in accordance with ANSI Std C63.19-2001 [B1] are described in Annex E.
Most EM field measurements are made in the frequency domain, either at a single frequency or at a number of frequencies. The ever-increasing susceptibility of electronic circuits has awakened interest in transient EM phenomena such as electrostatic discharge (ESD), electromagnetic pulse (EMP), and system-generated transients, such as automotive ignition noise. The measurement of these transient fields requires EM field probes and sensors that can accurately replicate the transient wave shapes, thus requiring an equivalent bandwidth of decades. The calibration of time domain sensors necessitates procedures that are significantly different from those for the frequency domain sensors.
The electric or magnetic field sensor and/or probe calibration requirements depend on the design and the manufacturer's specifications. The calibration shall address the amplitude response, frequency response, accuracy (uncertainty), linearity, and isotropy. Additionally, the calibration may address response time, time constant, and response to signal modulation.