Random-Walk Technique for Measuring the Electromagnetic Environment in Electrically Large Reflective Spaces

An efficient and accurate “walk-around” technique is presented for making on-site measurements of the electromagnetic environment in enclosed reflective spaces found in ship below-deck compartments, aircraft cabins and bays, and buildings such as hangars and prefabricated metal storage facilities. To assess the potentially disruptive or harmful effects to electronics equipment or ordnance from accumulated radio frequency emissions, these reverberant spaces are characterized as overmoded complex cavities, and a statistical analysis is exercised to obtain important information about maximum and average power densities in the space and their associated uncertainties. This new technique utilizes lightweight and portable test equipment, and is particularly well suited for measurements in field-operational spaces, where the use of more conventional techniques has been proven to be very difficult due to severe constraints on time, working volume, equipment size and weight, and test costs. The efficiency and accuracy of the walk-around technique are demonstrated in this paper by comparison to measurements obtained by the more conventional techniques in a large reverberation chamber. Results indicate a substantial reduction in test time, a vast improvement in the ease of test execution that can be realized at remote sites, and equal or better accuracy in the characterization of the electromagnetic environment.