Measurements of Dielectric Properties of Chang’E‐5 Lunar Samples

Abstract The Chang’E‐5 samples are the youngest lunar materials collected to date. Determining their dielectric properties is essential for understanding the physical characteristics of lunar regolith and refining its dielectric model. In this study, the real part of permittivity and the loss tangent of the Chang’E‐5 samples were systematically measured across a wide frequency range of 0.2–12.2 GHz. The results extend the existing database of lunar regolith dielectric properties and fill a key gap in this frequency band. The measurements show that the real part of permittivity exhibits strong frequency stability and increases exponentially with density. In contrast, the loss tangent decreases with frequency, with a decay rate significantly lower than that of Apollo samples below 0.2 GHz. Moreover, the correlation between loss tangent and density weakens near 10 GHz. This behavior differs from Apollo samples, which exhibit increasing loss tangent with density below 10 GHz. Based on these laboratory measurements, we revised the empirical coefficients for the real part of permittivity and loss tangent previously derived from Apollo data alone. These findings provide new experimental constraints for accurate modeling of lunar dielectric properties and their application in in situ exploration.