IEEE C63.5-2017 pdf download
IEEE C63.5-2017 pdf download.American National Standard for Electromagnetic Compatibility-Radiated Emission Measurements in Electromagnetic Interference (EMI)Control-Calibration and Qualification of Antennas (9 kHz to 40 GHz).
5. Standard site method (30 MHz to 40 GHz)
5.1 General considerations
5.1.1 Basic parameters for SSM antenna calibrations
The standard site method (SSM) (Smith [B40]) applies to AF measurements from 30 MHz to 40 GHz. Figure 2 identifies the required site attenuation (SA) measurement geometry. As indicated in Clause 1, consistent with international standards such as CISPR 16-2-3:2010 [BlO], the FSAF shall be used for radiated emission measurements. For the purposes of measuring to ASC C63 R standards, FSAF shall be used for biconical antennas (obtained by applying the correction factors in Annex G), and NFSAF shall be used for LPDA and hybrid antennas. In the following subclauses, descriptions of the SSM parameters are given for two frequency ranges: a) frequencies from 30 MHz to 1 GHz for measurements over a ground plane (see 5.1.2), and b) frequencies from 1 GHz to 40 GHz for measurements in a free-space environment (see 5.1.3).
a) An AC’S appropriate for the AUC frequency range shall be used for SSM.
b) The test site and measurement instrumentation requirements in 4.3 shall be met.
c) Horizontal polarization is required for antenna calibration up to 1 GHz, based on the following rationale:
I) Mutual coupling between the antenna and the orthogonal cable is negligible,
2) Scattering from the cable is negligible,
3) The horizontally polarized ground plane reflection is less sensitive to differences in the ground plane conductivity and permittivity than the vertically polarized reflections,
4) Ground plane edge reflections are smaller for horizontal polarization.
b) AF measurement errors caused by site anomalies may be evaluated using the procedure in L.4.7 (see also J.3).
c) Signal cables shall be routed straight back from the antenna connector at least 1 m before being routed down vertically to the ground plane.
d) Signal cables that are routed orthogonal to the antenna elements will have minimal coupling to the antenna field, but the cable shields can carry external currents caused by balun imperfections; see also 4.3 item d). Also, portions of the cables that are not straight down or straight back will couple to the antenna fields; see, e.g., DeMarinis [B 13] and [B 12] for further discussion of the preceding effects.
e) 10 dB attenuators, with a return loss of greater than 1 5 dB, shall be connected to the transmit antenna and receive antenna, for matching purposes between each antenna and cable.
c) Free-space test environment requirements:
I) The validity of the free-space test environment at the selected antenna height shall be verified by measuring the site insertion loss in both horizontal polarization and vertical polarization. The difference between the two measurement results shall he less than 1 dB.
2) If the requirement of 5.1 .3 item ci) is not met, then raise the height of both antennas, or add RF absorber material on the ground plane between the antennas, until the requirement is met.
3) Time gating of the data may also be used to meet the requirement of 5.1.3 item ci) and to obtain free-space AFs (FSAFs) (i.e., see Camell Ct al. [B4j and Annex K), as outlined in 5.1 .3.2.
d) Standard gain horn antennas are pyramidal horn antennas designed to have the gain (or AF) established by their physical dimensions, the frequency of interest, and the distance to the measurement point (see
12.3.1 of IEEE Std 149-1979). While reasonable gain values can be calculated using the physical dimensions and analytical formulas, a calibration measurement provides AFs specific to a particular antenna along with the associated traceability. For the purposes of this standard, it is acceptable to determine AF for a standard gain horn by calculation from the physical dimensions, or using individual antenna calibration measurements in accordance with this subclause. Either method of determination of AF will have its own stated measurement uncertainty.
5.1.3.2 Time gating to determine FSAFs above I GHz to 40 GHz
Time-domain processing techniques may be used to remove unwanted signals from antenna calibration measurement results to emulate a free-space environment response. By applying proper gating techniques to site insertion loss data in the time domain, a free-space environment can be mathematically simulated. This method may be accomplished by using internal functions of a typical vector network analyzer (VNA), or by post-processing of transmission measurement results. See Camell et al. [B4] and Annex K for guidance and details about appropriate gating procedures. Time gating may be applied to determine FSAF along with the other basic conditions of 5.1.1 and 5.1.3.
