On-Site Radiated Emissions Measurements in Semireverberant Environments

Abstract

Radiated emission tests are generally performed in either free space, reflection-free environments, such as an open area test site or semi-or full-anechoic chambers, or in reverberation chambers. This paper describes measurements in semireflecting environments such as an office, a workshop of a large industrial apparatus or installation. The objective is to develop test methods and associated correction factors and uncertainties for measurements which are performed on-site, near large industrial apparatus which cannot be moved to an EMC laboratory. The measurement technique is based on reverberation chambers and tools such as insertion loss, quality factor, as well as a goodness of fit test were used to perform the test site analysis. The advantages and drawbacks of on-site measurements of large apparatus are discussed. A simplified, but not limited to perfect reverberation chambers, method of finding the measurement uncertainties was used to calculate the errors associated with imperfect reverberation and field uniformity, as well as the influence of noise and equipment nonlinearities. The results are given in form of a guideline, concluding that such measurements are possible.

A Review On Links Between Different EMC Test Environments in Medical Technologies

“…In [29], a measurement technique based on RC (and other parameters including Q-factor, IL, and GoF) for on-site emission measurements in semi-reverberant environments was introduced. A simplified method to determine uncertainties for calculating correction factors was given.…”

Risk-based EMC Approach in Hospital Environment

“…Various papers show measurements of EM fields in hospitals [15], [16], [17] justifying the importance of the environmental influence, implying that the risk-based approach is more practical than the rule-based approach. It is very important to keep in mind that the environment in the hospital is much more complex than the free space because a hospital can behave like a semireverberant environment [18], [19]. The location of the sources changes unpredictably over time as people in the hospital carry mobile devices, electric cars move through the corridors 24/7, elevators move from floor to floor [20], antennas are placed in different positions inside or outside of the building, routers are present inside rooms, etc.…”

Characterization of Reverberation Chamber - A Comprehensive Review

“…The total antennas efficiencies of the transmit and receiving antennas in an RC are estimated using (18) (18) In (18), S F S nn T x/Rx is the free space reflection coefficient of the 'nth' Tx/Rx antenna in free space. It can also be predicted from the measured ensembles averaged reflection coefficient of the antenna in an RC i.e.…”

“…The RC offers comprehensive advantages of generation of high field strength with a moderate input power, shorter testing time, large testing volume, and no EUT rotation requirements as compared to open area test sites (OATS) and semi/full anechoic chambers [5], [18]- [21]. The assurance of spatial field uniformity depicting the overmoded or wellstirred condition of RC is essential before the conduction of any kind of testing in an RC.…”