ANSI IEEE C63.5-2004 pdf download American National Standard for Electromagnetic Compatibility–Radiated Emission Measurements in Electromagnetic Interference (EMI) Control–Calibration of Antennas (9 kHz to 40 GHz)
This value will represent the free-space antenna factor within an error smaller than the measurement uncertainty. This error is negligible when these antenna factors are used for product emission measurements. 3.6 ground plane: A conducting surface or plate used as a common reference point for circuit returns and electric or signal potentials.
3.7 ideal site: A test site on which the reflective surface is flat, level and has infinite conductivity and size.
3.8 measurement geometry: A specified polarization, separation distance, transmitting height, and receiving height(s) for a pair of antennas during their antenna factor measurement.
3.9 normalized site attenuation (NSA): Site attenuation divided by the free-space antenna factors of the transmitting and receiving antennas (all in linear units). Results can be stated in decibel units.
3.10 radiated emissions test site: A site with specified requirements suitable for measuring radio interference fields radiated by a device, equipment, or system under test.
3.11 site attenuation: The minimum relative insertion loss measured between two polarization-matched antennas located on a test site when one antenna is moved vertically over a specified height range.
3.12 standard antenna calibration site: A site comprised of a flat, open-area, devoid of nearby scatterers such as trees, power lines, and fences, that has a large metallic ground plane (see ANSI C63.7-2005).
4. General test conditions
4.1 Introduction This standard provides a means of measuring antenna factors for most types of antennas used in emissions testing. These antenna factors can be used for either vertically or horizontally polarized measurement at distances from the equipment under test of 3 m or more. Table 1 provides an index of antenna type to measurement method.
Free space antenna factors can be developed for biconical dipole antennas using Clause 5 and Annex G (see Table 1). Using the methods in Clause 5 and Annex G will provide more accurate results for biconical dipole antennas than the use of Clause 5 alone. See Annex F for additional information on the rationale of GSCF for biconical dipole antennas.