We have measured the relative complex permittivity of epoxy resinous material under changes in temperature. The variation of the temperature of the single-layer absorber has been analyzed using the FDTD-HTE method. As a result, the following three aspects were confirmed:1. If the relative complex permittivity of the sample depends on the temperature, its real part increases from 14.7 to 16.8, and its imaginary part increases from 1.5 to 4.2 under the condition that the temperature increases from 24°C to 160°C. 2. The temperature inside the single-layer absorber increases rapidly with increased irradiation power. It is observed that the heat generated inside the absorber tends to equal to heat radiated from the surface of one after 120 min of irradiation. The stabilization temperatures are about 40°C at 100 W/m 2 , about 110°C at 500 W/m 2 , and about 170°C at 1000 W/m 2 . 3. The absorption of the absorber becomes 25 dB in the initial state. Then the absorption increases gradually, shows a peak value of about 60 dB, and decreases gradually after that.In the near future, we would like to measure the temperature characteristics of various materials for the radiowave absorbers. Moreover, we will also try to examine the absorption characteristics of other types of radiowave absorbers under irradiation power.

generate a sufficiently long time response for accurate frequencydomain parameter estimation. The results show that the PSO can efficiently obtain the optimal hyperparameter value needed in the LS-SVM algorithm. Also, the PSO_LS-SVM method can greatly reduce the CPU time as compared to the direct FDTD method. In the future, the PSO_LS-SVM will be widely used in computational electromagnetics.

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