## 3 Experiment Results  
In order to verify the absorption performance of the designed absorber, a 300 mm \(\times\) 300 mm sample was fabricated, as shown in Figure 8. The production flow chart of the sample is shown in Figure 9. The preparation process was consistent with that described in our previous paper [38]. Firstly, the conductive glass was obtained by coating the ultra-white glass with ITO film by the magnetron sputtering technique. We prepared conductive glass with sheet resistance of 3 \(\Omega\)/sq, 45 \(\Omega\)/sq and 200 \(\Omega\)/sq, respectively. Secondly, the corresponding patterns on the conductive glass were etched by laser-etching technology. Finally, two layers of PVB films were used to combine the three layers of glass into a complete wave-absorbing structure under high temperature and pressure. At the same time, the use of PVB also helped to reduce the profile because PVB reduces the refractive index difference between interfaces. We used an autoclave for this lamination process.  
Figure 8: Photograph of the fabricated absorber sample.  
Figure 7: Absorption performance at different polarization angles \(\varphi\).  
We measured the absorption performance of the transparent absorber by the arch test system. The comparison of the measured and simulated absorptance of the transparent absorber is shown in Figure 10. It can be seen from Figure 10 that the experimental and simulated results are in good agreement. The overall trend of the measured results is consistent with the simulation results. The measured results also have two absorption peaks, at 7.1 GHz and 14.3 GHz respectively. It can be found that the two absorption peaks of the experimental results moved slightly towards low frequency and high frequency, respectively; thus, the absorption bandwidth was slightly increased (6.0-16.7 GHz, absorptance > 85%). At the same time, the experimental values of absorptivity in the absorption band were slightly lower than the simulation results, which was reduced by about 3%. The sheet resistance SR\({}_{2}\) of the second ITO layer was non-uniform and less than the optimal value, which may cause this spectral displacement, as shown in Figure 4b. In addition, PVB was used to bond three layers of glass, which resulted in the thickness between the glasses not being precisely controlled, which may also have led to the reduction in the absorption peak. Although there were some deviations between the experimental value and the simulation value, these deviations are within the acceptable range and can be reasonably explained, and the deviations can be reduced by optimizing the process parameters.  
The optical transmittance of the fabricated absorber was measured by the Agilent spectrophotometer (Carry5000), as shown in Figure 11. It can be observed that the average transmittance of the transparent absorber in the visible band was approximately 85.7%. Therefore, the absorber designed in this paper proved to have a high transmittance in the visible band. This property can effectively improve the working environment in practical applications.  
Figure 10: Comparison of measured and simulated absorptance of the absorber.  
Figure 9: The production flow chart of the sample.  
Finally, the characteristics of the previously reported transparent absorbers are summarized in Table 2. The results show that the proposed absorber not only has a wide absorption band, but also has advantages in relative thickness and visible light transmittance. Therefore, its broadband absorption, high transparency, low profile, polarization insensitivity and oblique incidence stability mean that the proposed transparent absorber has potential use in many practical applications, such as observation windows in communication vehicles, electromagnetic shielding rooms and transparent radio-frequency identification systems.