To explore the sensitivity for absorber, PI films of different thicknesses were spin coated on the absorber. The absorber sensor characteristics were simulated using CST Microwave Studio (Fig. 5). From the above analysis, we know that the third peak was relatively weak, so we mainly discuss the sensing characteristics for resonances and . Figure 5(b) shows the simulated absorption spectra of the absorber under different thicknesses () of solid analyte; the red frequency shifts of the resonance for the film thicknesses 4, 8, and were 90, 116, and 134 GHz, respectively. The frequency shifts of 198, 364, and 491 GHz for the 4, 8, and thicknesses of the analyte for the resonance were significantly higher than those of frequency shift . Additionally, the change in the amplitude absorption was apparent with the different thicknesses of the PI film for the resonance .