Draft Standard for Electromagnetic Compatibility-Radiated Emission Measurements in Electromagnetic Interference (EMI) Control-Calibration and Qualification of Antennas (9 kHz to 40 GHz)
This standard provides methods for determining antenna factors (AFs) and associated parameters of antennas used to perform radiated emission measurements in electromagnetic interference (EMI) control from 9 kHz to 40 GHz. Antennas covered by this standard are linearly-polarized antennas@ such as loops@ rods (monopoles)@ tuned dipoles@ biconical dipoles@ log-periodic dipole arrays@ hybrids (i.e.@ combination broadband dipole and log-periodic dipole array antennas)@ broadband horns@1 etc.@ that are used in measurements defined by various ASC C63? emission measurements standards (e.g.@ ANSI C63.4 and 507 ANSI C63.10). The associated compliance measurement requirements are provided within other ASC C63? standards. The methods used for antenna calibration measurements include the standard site method (SSM)@ the reference antenna method (RAM)@ the equivalent capacitance substitution method (ECSM)@ the standard transmit loop method (STLM)@ the standard antenna method (SAM)@ and the standard fieldmethod (SFM). In 4.1@ the latter three methods are included in this document by reference Harmonization with international standards (Goedbloed [B22]@ CISPR 16-2-3 [B10])2 is obtained as much as possible primarily by requiring that a single measured antenna factor be used at each frequency and that it be a free-space or near-free-space antenna factor. For 30 MHz to 1000 MHz@ antennas are measured using a test site with a ground plane and a measurement geometry that yields near-free-space AFs; above 1 GHz@ a free-space environment is used. The free-space condition is obtained when the site reflections are removed by applying RF absorber to the ground plane@ by increasing the antenna heights@ or by time domain gating of the data. Measurement conditions are described and acceptable measurement methods are listed in Clause 4. The SSM is explained in Clause 5@ and the RAM in Clause 6. For monopoles@ the ECSM is described in Clause 7. Normative annexes cover monopole characteristics (Annex E)@ free-space correction factors for tuned dipole antennas (Annex F) and biconical dipole antennas (Annex G)@ measurement procedure for geometry specific correction factors (GSCF) (Annex I)@ requirements for antenna calibration sites (ACS) (Annex J)@ and guidelines for using time-domain gating (Annex K). The word ??shall?? is used in this document to indicate mandatory requirements. The words ??should?? or??may?? are used to indicate that among several possibilities one is strongly recommended but not mandatory. Text in this document shall override text in normative references in the event of conflicting requirements. 1 In this document the term ??horn antenna?? includes double-ridged waveguide horns@ quadruple-ridged waveguide horns@ rectangular waveguide horns@ pyramidal horns@ optimum-gain horns@ octave-band horns@ and standard-gain horns. The term ??broadband horn?? typically refers to ridged waveguide horns (see also the definition of ??broadband antenna?? in 3.1). 2 The numbers in brackets correspond to those of the bibliography in Annex O