Static and Dynamic Permittivity Measurement of High Explosives in the W Band to Investigate Shock and Detonation Phenomena

Abstract

AbstractRadio interferometry techniques are often used to investigate shock and detonation phenomena thanks to the radio‐transparency of high explosives in the gigahertz frequency band. These techniques require the knowledge of the permittivity of studied explosives. Although the permittivity has been thoroughly studied for many materials, very few data are available at high frequencies (>75 GHz) for high explosives. In this paper, we report static measurement data of the permittivity for various reactive materials using the standard line transmission method between 75 GHz and 110 GHz (W frequency Band), and we present dynamic measurement results at 94 GHz obtained from the so‐called detonation wavefront tracking method. It is shown that the measurement results provided by these two methods are in good agreement. As a consequence, this work validates the detonation wavefront tracking method for the dynamic measurement of high explosives permittivity, and shows that the static experimental results are relevant for shock wave propagation analysis from millimeter‐wave measurement techniques.