Permeability and permittivity uncertainty effects in modeling absorbing coatings and ferrites on cables

A semi-empirical approach for predicting the performance of multiphase composites at microwave frequencies

“…The ability to predict R, T, and A based on volume loadings of the phases for these materials is robust, although future studies are required to fully assess the applicability to different materials and different setups. Additionally, we note oscillations at higher frequencies (above 15 GHz), which could be artifacts of the sample holder used here [54][55][56]. Future work could focus on using a more robust sample holder, such as the 3.5-mm precision adapter as used by Jing, et al, to provide better resolution at higher frequencies [56].…”

“…We note that the quality of the washer-like sample, its placement in the coaxial line, the presence of gaps, and the accuracy of thickness measurements may create non-monotone artifacts, particularly at approximately 18 GHz [54][55][56]. We used this approach to assess the feasibility of the approach we outline in Section 3.…”

“…Future analyses could also incorporate fibers, which have lower percolation thresholds and could achieve useful shielding behavior at lower volume loadings/weights. We note the increase in A and the decrease in R above 15 GHz, which would be approximately the frequency limit of the 7 mm line [54][55][56]; therefore, we turn to the calculated  and  for one of the samples in Figure 2 to explore their behavior at these frequencies. Figure 3 shows the measured  eff and  eff for the sample containing 10% flakes and 20% spheres.…”

“…Figure 3 shows the measured  eff and  eff for the sample containing 10% flakes and 20% spheres. Measured  eff and  eff can then be used to calculate R, T, and A with slight variations from directly extracting R, T, A above 18 GHz due to the nonmonotone artifacts [54][55][56]. We point out that while we extracted and  from our measurements, we fit A x and s using R, T, and A because these potential non-monotone artifacts that may arise at approximately 18 GHz [54][55][56] may impact the ability to accurately extract  eff and  eff using our sample setup.…”