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American National Standards Committee (ANSC) C63's (Electromagnetic Compatibility) active technical contributors will meet in person at UL Solutions in Raleigh, North Carolina, the week of May 13, 2024.  The committee convenes regularly both virtually and in person to address the standards maintained and developed by ANSC C63, including the seminal ANSI C63.4 “Methods of Measurement of Radio-Noise Emissions from Low-Voltage Electrical and Electronic Equipment in the Range of 9 kHz to 40 GHz,” as well as the new ANSI C63.25 series of standards for EMC test site validation.  

The series includes C63.25.1 “Validation Methods for Radiated Emission Test Sites, 1 GHz to 18 GHz,” which includes the application of Time Domain (TD) and Site Voltage Standing Wave Ratio (SVSWR); new procedures for site validation measurements in C63.25.2 (30 MHz to 1 GHz); and a novel technique using Cylindrical Mode Filtered SVSWR (CMF SVSWR) measurements for test site validation and antenna calibration from 18 GHz to 40 GHz included in the draft standard C63.25.3.

ANSI C63.25.3 is particularly significant since the standard provides the latest test methodology for validating performance of an EMC test site in the frequency range of 18 GHz to 40 GHz, the natural evolution of measurements for the C63.25 standard series since the publication of the standards ANSI C63.25.1 and C63.25.2.  “This is a new frequency range to explore for EMC test sites.  A standard in this frequency range currently does not exist, yet industry demand for testing products at higher frequencies is increasing,” said Zhong Chen, Chief Engineer with ETS-Lindgren and Vice Chair of the C63 Committee.  “C63 is addressing this industry-driven challenge with the new draft standard C63.25.3.  Our goal is to provide a site validation measurement technique that is relatively easy and fast to perform and, most importantly, yields results that are reliable and repeatable.  Time is money with commercial test and internal R&D labs, so if the new technique expedites the site validation measurement process, then test labs have more time for customers and staff.”

A hallmark of the draft C63.25.3 standard is the new capability to provide greater information beyond the basic chamber reflection levels.  “The current SVSWR standard method under-samples data collection and offers no information on the coverage of the receive antenna; only at a few positions within the quiet zone are evaluated.  In contrast, the CMF SVSWR method specified in C63.25.3 provides a comprehensive view of the chamber reflection levels as well as the quality of the entire quiet zone, all with a faster test time compared to the traditional SVSWR method,” offered Mr. Chen.

In light of the significance of the draft C63.25.3 standard in expediting EMC test site validation time as well as offering greater performance diagnostics, Mr. Chen and Yibo Wang, RF Engineer with ETS-Lindgren, have produced a video demonstration of the CMF SVSWR method, now available here, to educate test lab operators and managers on this novel technique.  Viewers will learn how the CMF SVSWR is measured by placing the transmit antenna (typically a low-gain omni-directional antenna) at the edge of an EMC test chamber turntable and performing a single-cut vector-pattern measurement.  A comprehensive evaluation of an EMC chamber quiet zone is then readily measured without any special positioning fixtures.  The video shows the entire measurement process, including the post-processing, which can be performed in real time.

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