# Research on Penetration Loss of D-Band Millimeter Wave for Typical Materials
## 3 Results  
Figure 8 and Table 4 show the experimental measurement results of placing occluders of different materials in the 100-m D-band mmWave wireless transmission experiment. It can be observed from the experimental results that the attenuation of the D-band millimeter-wave signal transmission by obstacles is positively correlated with the thickness or number of obstacles. Signal attenuation increases with the thickness and number of obstacles. For example, in Figure 8a, the penetration loss of one pot of vegetation is about 12 dB, the penetration loss of two pots of vegetation is about 16 dB, and the penetration loss of three pots of vegetation is greater than 21 dB. Due to the irregular distribution of vegetation stems and leaves, the power of the signal transmission path is greatly reduced when the signal transmission path is blocked by vegetation. It is important to emphasize that attenuation varies greatly with the irregular nature of the vegetative medium, which means that penetration losses depend on a wide range of vegetation types, densities, and the actual amount of water contained. Figure 6: Schematic diagrams of the relative position of the occluders and the transceiver in the experiment. Figure 7: The separation of the pots. \begin{table}
\begin{tabular}{c c} \hline \hline
**Material** & **Size (cm2)** \\ \hline Wood board & 49.2 \(\times\) 35.8 \\ Regular glass & 88.2 \(\times\) 42.9 \\ Slate & 59.7 \(\times\) 39.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The details about the occluders. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multirow{2}{*}{\begin{tabular}{c} **Thickness** \\ **(m)/Number** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Penetration** \\ **Loss (dB)** \\ **140 GHz** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Penetration** \\ **Loss (dB)** \\ **145 GHz** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Penetration** \\ **Loss (dB)** \\ **150 GHz** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Loss (dB)** \\ **155 GHz** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Loss (dB)** \\ **160 GHz** \\ \end{tabular} } \\ \hline \multirow{2}{*}{Vegetation} & One pot & 11.9 & 11.8 & 11.8 & 11.7 & 12.1 \\  & Two pots & 16.0 & 16.0 & 15.9 & 16.1 & 17.0 \\  & Three pots & 21.7 & 21.5 & 21.6 & 21.3 & 22.0 \\ \hline \multirow{2}{*}{Glass} & 0.005 & 4.5 & 4.6 & 4.3 & 4.1 & 5.0 \\  & 0.01 & 9.0 & 8.9 & 8.8 & 8.7 & 10.1 \\ \hline \multirow{2}{*}{Wood board} & 0.003 & 2.5 & 2.4 & 2.4 & 2.5 & 2.5 \\  & 0.006 & 6.0 & 6.2 & 5.9 & 7.5 & 6.4 \\  & 0.0175 & 24.9 & 25.1 & 23.1 & 25.1 & 26.5 \\ \hline \multicolumn{2}{c}{State} & 0.05 & 22.0 & 19.9 & 19.2 & 21.9 & 22.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The attenuation loss of D-band millimeter-wave signal through different obstructions measured experimentally. Figure 8: The attenuation loss of D-band millimeter-wave signal through different obstructions measured experimentally. The obstructions are listed as: (**a**) the relationship between penetration loss and frequency under the shielding of different numbers of vegetation; (**b**) the relationship between penetration loss and frequency under the shielding of different thicknesses of wooden boards; (**c**) the relationship between penetration loss and frequency under the shielding of different thicknesses of glass; (**d**) the relationship between penetration loss and frequency under the shielding of 5 cm-thick slate. In Figure 8b, the loss of the 0.3 cm-thick board is about 2 dB, the loss of the 0.6 cm-thick board is about 6 dB, and the loss of the 1.75 cm-thick board is greater than 23 dB. Penetration loss may be proportional to the thickness of the occluded board, and D-band mmWave signals cannot penetrate boards thicker than 1.75 cm. As shown in Figure 8c, the loss of 5 mm-thick glass is about 4 dB, and the loss of 10 mm-thick glass is about 9 dB. Path loss can be positively related to the thickness of the shielding glass.