This program generates reference EM fields and calibrates EM probes required for their accurate measurement. Accurate EM field measurements are needed to characterize our wireless world and ensure that the valuable electromagnetic spectrum is optimally used, that electronic systems are compatible and neither sources nor victims of EM interference, and that people are not exposed to hazardous fields. As instrumentation and electronics achieve higher clock rates, EM field parameter metrology is needed at ever higher frequencies. The program is working to extend current methods and facilities to higher frequencies, and develop new test methods to increase accuracy and reduce measurement costs.
The program is working on extending open area test site test methods to frequencies above the 1 gigahertz specified by most international electromagnetic compatibility (EMC) standards. Fully anechoic chambers are accepted as standard sites for approximate free-space measurements. Time-domain methods are being studied as a way to measure the characteristics of these rooms and to improve the results obtained therein. This type of chamber is also being evaluated for EMC product testing up to 40 gigahertz. Closed test systems such as transverse EM cells have been widely adopted for testing small antennas, sensors, and probes, but are normally limited by geometrical constraints to below 1 gigahertz. EEEL recently finished construction and testing of a new closed-cell co-conical geometry system that can be used to test such devices up to 45 gigahertz. This new test fixture reduces test times from weeks to hours.
The program provides information to standards organizations to help correlate measurements between various EMC test facilities. The program also cooperates with the national test laboratories of our international partners to perform round-robin testing and comparison of standard antennas and probes. This assures international agreement in their performance and reduces the uncertainties in the areas of metrology that affect international trade. Our goal is to develop and evaluate reliable and cost-effective standards, test methods, and measurement services related to complex EM fields for EMC of electronic devices and other applications in health, defense, and homeland security.