| Popis: |
RF absorbers dissipate the incident electromagnetic wave by converting the RF energy into heat. In many applications, the absorbers can be subjected to high power incident fields. It is imperative to characterize and analyze the thermal behaviors for these high power applications. In this paper, a multi-physics (of EM and thermal) study has been conducted. The absorbers are first simulated in the ANSYS HFSS for electromagnetics. The absorbers are placed under plane wave incident field as well as from a pyramidal horn antenna in the near field. The output of the HFSS model is then imported to the thermal and computational fluid dynamics (CFD) tool, ANSYS ICEPAK. In order to obtain accurate thermal properties of the material, an experimental setup was designed. The simulation results are validated against measured data. Several effects are shown to affect the absorber internal temperatures for the same incident field level at the front of the absorbers, such as the antenna test distance to the absorber, the shape of the pyramid, and the measurement frequency. These simulation data provide greater insights into the heat dissipation and temperature distribution inside the absorbers. |
