Low-Level Radiated Emission Measurements Using the Chamber Gain of a VIRC

Abstract

For performing electromagnetic compatibility (EMC) as well as TEMPEST radiated emission (RE) measurements, conventional test sites such as anechoic rooms are used. These sites are location-bound, usually time-consuming, and require low-noise receivers and high-gain antennas along with multiple testing positions of the equipment under test (EUT). To overcome those limitations, the use of a vibrating intrinsic reverberation chamber (VIRC) is investigated as an alternative test environment for RE measurements, and a novel chamber-factor-based conversion method is introduced to enable a comparison with the conventionally applied semi-anechoic chamber (SAC). EUTs with distinct directivities and frequency-dense generated emanations are tested. Good agreement with the respective SAC measurements validates the proposed conversion method. The average difference between the two test sites is shown to be 4 dB with the introduced conversion method. The results expose the capabilities of the VIRC in terms of measurement time, cost, convenience, and efficiency while they also highlight the ability of the VIRC to detect low-amplitude signals close to or below the noise floor of the receiver because of its chamber gain, extending the measurable dynamic range for weak emissions.