Two-Dimensional Full-Vectorial Finite Element Analysis of NRD Guide Devices

Nonradiative dielectric waveguide (NRD guide) is a promising platform for realizing compact millimeter waveguide circuits. NRD guide devices have been simulated by several numerical simulation approaches so far and these approaches treat 3-D structure because electric and magnetic fields in NRD guides vary in whole directions. In this letter, we propose a 2-D full-vectorial finite element analysis for efficient simulation of NRD guide devices

Optimal design of NRD guide devices using 2D full-vectorial finite element method

In this paper, we propose an optimal design approach based on a concept of mosaic-like structure for achieving high performance NRD devices. In order to improve design efficiency, we employ the recently proposed two-dimensional full vectorial finite element method (2D-FVFEM) which can accurately model 3D structure of NRD as a numerical simulation method. As an optimization method, we employ either direct binary search (DES) algorithm or genetic algorithm (GA) depending on design problems. In order to show the usefulness of our approach, design examples of crossing and T-branch waveguides are considered and high transmission efficiency greater than 99.9% for crossing waveguide and 49.8%: 49.8% for T-branch waveguide is achieved. The numerical results by 2D-FVFEM are verified by 3D-FVFEM

Relationship of external field strength with local and whole-body averaged specific absorption rates in anatomical human models

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines and the IEEE C95.1 standard are currently under revision. In the guidelines/standard, the dominant effect for electromagnetic field exposures at frequencies above 100 kHz is the thermal effect. The whole-body-and 10g-averaged specific absorption rates (SARs), which are surrogates for core and local temperature elevations, respectively, are set as metrics for exposure evaluation. The external field strengths or incident power density, corresponding to the limit for SARs, are also used as metrics for practical compliance purposes. Although the limits for the SARs are identical amongst the guidelines/standard, the limits for the external field strengths differ by a factor of 7.4-12.9 in an intermediate frequency range (100 kHz-100 MHz). Due to the fact that the standard/guidelines were published before the computation with anatomical human models was available, it is worth revisiting the relationship between the SARs and external field strengths by computations using the human models. Intercomparison using different numerical codes was also performed to verify the results. For the main finding, as expected, the 10g-averaged SAR was a less restrictive factor for whole-body exposure over the frequencies considered in this paper. It was also found that the relationship between SARs and external field strength was satisfied, but was more conservative in the ICNIRP guidelines, whereas there were slight discrepancies below 30 MHz in the IEEE standard. The computational results would be useful for revising the permissible external field strength based on scientific results.Peer reviewe