High Performance Parallel Computing for FDTD Numerical Technique in Electromagnetic Calculations for SAR Distribution Inside Human Head HESHAM ELDEEB # , HALA ELSADEK # , MAHA DESSOKEY # , HAYTHAM ABDALLAH # and NADER BAGHERZADEH * # Electronics Research Institute, Cairo, EGYPT # helsadek@mcit.gov.eg * Electrical and Computer Engineering, Henri Samuli school of Engineering, University of California, Irvine, Irvine, CA, USA Abstract: - The interest in high performance computing (HPC) nowadays has increased the need of computational resources to solve large scale problems. The technological improvements over the past few years in areas such as microprocessors, memory, networks, and software, have made it possible to assemble groups of economical personal computers and/or workstations into a cost effective system with high processing power. In this paper, three HPC platforms are utilized and performance is compared to calculate the electromagnetic power absorbed by human head due to radiation from antennas of handheld devices. Parallel processing performance comparison of the three platforms shows that the IBM BlueGene supercomputer still preserves the largest speedup and efficiency. However the cluster and grid computing offer far cheaper solutions for small to moderate size problems beside the more utilization of the already existing computing resources. Key-Words: - High Performance Computing (HPC), cluster computing, grid computing, BlueGene supercomputer, Specific Absorption Rate (SAR), Finite Difference Time Domain (FDTD), Microstrip antenna 1. Introduction Nowadays, it seems that electronic designs increasingly require electromagnetic characterization. Due to the ever increasing usage of the wireless hand held devices that radiates electromagnetic waves in all the surrounding environments. To facilitate such analysis, numerical techniques have been developed. Among the most common computational techniques for lossy materials is the Finite Difference Time Domain (FDTD) method. The FDTD is one of the most common and robust numerical techniques that are trusted in computing scattering inside inhomogeneous materials such as the human body [3-8]. The main problem with this technique is the large time and memory consumption when solving for real practical scattering problems. The time consumption increases by a factor related to the multiplication of the three dimensions of the computational domain and the number of time steps. Run times in the order of hours, days, or even longer are common when solving electromagnetic waves problems of realistic size. Thus, the need for parallel processing algorithms becomes a must especially for on spot/ real time applications. In the FDTD, the Electric field E and the magnetic field H are evaluated at each time step from the neighbourhood fields in the previous time step. Hence no need for more matrix inversion. The near-field is also evaluated directly and the far field can then be evaluated using near-field to far-field transformation as shown in eq. 1 to eq. 6, which represents the six fields’ components at each discretized domain cell as shown in figure 1, assuming a dielectric material having a dielectric constant ε , permeability μ and conductivity σ. ( ) ( ) + + = + + k j, 1/2, i n x Ε a C k j, 1/2, i 1 n x Ε ( ) ( ) { k j , 2 / 1 , 2 / − i n z k j i n z e N 1 2 / 1 , 2 / 1 , 2 / 1 2 / 1 + + Η − + + + Η ( ) ( ) } 1/2 k j, 1/2, − i 1/2 n y Η 1/2 k j, 1/2, i 1/2 n y Η + + − + + + − (eq.1) ( ) ( ) + + Ε = + + Ε k j i n y a C k j i n y , 2 / 1 , , 2 / 1 , 1 ( ) ( ) { 2 / 1 , , 2 / 1 − 2 / 1 2 / 1 , 2 / 1 , 2 / 1 + + Η − + + + Η i n x k j i n x e N ( ) k j ( ) } k j , 2 / 1 , 2 / 1 + i n z k j i n z 2 / 1 , 2 / 1 , 2 / 1 2 / 1 − + Η − + + + Η − (eq.2) LATEST TRENDS on COMPUTERS (Volume I) ISSN: 1792-4251 114 ISBN: 978-960-474-201-1