Christophe Lemoine

Various estimations of composite Q-factor with antennas in a reverberation chamber

This paper deals with the estimation of the composite Q-factor in a reverberation chamber using one or two antennas (possibly a set of them). Most of Q-factor estimations provided in literature are based on the estimation of the ensemble average of the electric power captured at the terminal of a receiving antenna, the EM field being produced with another one. We first highlight that using two antennas and a vector network analyzer, three different estimations are possible and they are found experimentally to be almost equivalent. Second, removing one antenna the Q-factor may change mainly in the frequency range for which the Q-coefficient of an antenna is no more negligible. Furthermore a post-processing of these two types of measurements allows to extract an estimation of this Q-coefficient alone. This estimation is quite favorably compared to its theoretical estimation based on ideal random field hypothesis.

Design and Experimental Validation of a Mode-Stirred Reverberation Chamber at Millimeter Waves

The purpose of this paper is to analyze the behavior of a mode-stirred reverberation chamber at millimeter waves. An experimental chamber with 0.423m × 0.412m × 0.383m dimensions has been built taking into account mechanical, electromagnetic, and measurement constraints for operation in Ka, U, and V bands. Its design warrants a relatively high quality factor (9 ×104 at 60 GHz), which is confirmed by measurements using frequency stirring. The statistical behavior of the experimental electromagnetic field inside the chamber in the 58.5-61.5-GHz range is consistent with that of a classical reverberation chamber. To the best of our knowledge, this is one of the first reverberation chamber designed and optimized around 60 GHz. It can be used as a test facility for electromagnetic interference and compatibility measurements at millimeter waves as well as for bioelectromagnetic applications.

Characterizing integrated circuit susceptibility with on-chip sensors

With the growing concerns about susceptibility of integrated circuits to electromagnetic interferences, the need for accurate prediction tools and models to reduce risks of non-compliance becomes critical for circuit designers. However, on-chip characterization of noise is still necessary for model validation. This paper presents an on-chip noise sensor dedicated to the time-domain measurement of voltage fluctuations and failures induced by electromagnetic interference coupling.

Radiation pattern measurements in reverberation chamber based on estimation of coherent and diffuse electromagnetic fields

In a recent publication, authors showed that measurements of the maximum directivity of antennas were achievable in a reverberation chamber through extraction of the coherent part of the field. In this communication, we extend the method to the measurement of the radiation pattern within the main lobe of radiation. One is thus able to estimate the 3dB aperture of the antenna without need of an anechoic chamber. Some preliminary results are reported and possible improvements are discussed.

An empirical statistical detection of non-ideal field distribution in a reverberation chamber confirmed by a simple numerical model based on image theory

In this article, the effect of the size of the antennas on the distribution of the electric field observed in a reverberation chamber is analyzed. Our hypothesis is that the more the antenna is voluminous, the more the behavior of the chamber appears to be ideal through measurement analysis. A simple numerical model is presented and used to verify the phenomenon and give credence to the assumption.

A probabilistic approach to susceptibility measurement in a reverberation chamber

In this article, we propose an alternative approach for measuring the susceptibility level of an equipment under test in a reverberation chamber. Instead of using a statistical estimation of the maximum, our estimation is based on an estimation of the probability of failure of the equipment under test. We show through Monte Carlo simulations that the probability of failure of an equipment under test allows to predict with a good accuracy its susceptibility level. An experimental validation with a simple equipment under test shows that the susceptibility levels measured in a reverberation chamber are consistent with measurements performed in a GTEM cell.