Andrzej Karwowski

Adapting MoM With RWG Basis Functions to GPU Technology Using CUDA

In this letter, a CUDA-enabled graphics processing unit (GPU)-accelerated implementation of the method of moments (MoM) for solving three-dimensional conducting body-wire problems is presented. The solution is based on the mixed potential integral equation (MPIE) discretized using Rao-Wilton-Glisson (RWG) basis functions. The CUDA environment is employed to port a single-CPU sequential code to the parallel GPU platform, and some relevant issues are discussed. Numerical results are given for a helical antenna with a cylindrical cup reflector. The measured speedup of about eight times over the CPU implementation is demonstrated.

Efficient wide-band interpolation of MoM-derived frequency responses using Stoer-Bulirsch algorithm

Availability of computationally efficient techniques for system performance simulation over a broad frequency range is essential in electromagnetic compatibility. Deriving samples of the desired observable from frequency-domain computations at uniform intervals may be prohibitively time consuming for highly resonant structures. This paper examines a technique for generating of wide-band data from Method-of-Moments (MoM) simulation by employing the Neville-type Stoer-Bulirsch inter-polation algorithm supported by adaptive frequency sampling of the observable. The key feature of the approach is its ability to perform interpolation over a wide frequency band with a single rational interpolant. Sample numerical examples demonstrate capability of the approach to greatly improve computational efficiency of MoM-based simulation over a broad frequency band.

Improving accuracy of FDTD simulations in layered biological tissues

This letter demonstrates a possibility of improving accuracy of the continuous wave steady-state FDTD prediction of the EM field distribution in the layered biological tissues by reducing the numerical dispersion error via appropriate direct modification of the constitutive parameters of the tissues. The attractiveness of the approach lies in that the enhanced accuracy of the FDTD prediction is obtained at the negligible cost of a trivial pre-processing of the material parameters.

Using GPU accelerated version of MoM for solving scattering and radiation electromagnetic problems

In this paper, a CUDA-enabled GPU accelerated implementation of Method of Moments (MoM) for solving scattering and radiation electromagnetic problems is presented. The solution is based on the frequency-domain Electric Field Integral Equation (EFIE) formulation for arbitrary configuration of conducting bodies and wires. The CUDA environment is employed to port a single-CPU sequential code to the parallel GPU platform. Numerical results and measured speedups over CPU implementation are given for a testing structure.

Wide-Band Hybrid MM-PO Computational Electromagnetics Technique Using [Z] Matrix Interpolation and Adaptive Frequency Sampling

In this paper, we present a highly efficient computational electromagnetics technique for wide-band analysis of antennas radiating in the presence of electrically large conducting bodies (platforms). The technique is based upon the well known moment method-physical optics (MM-PO) hybrid formulation combined with the impedance matrix interpolation and a dynamic adaptive frequency sampling of the desired observable. Numerical examples are given to demonstrate considerable saving in both computer memory and CPU time offered by the proposed approach.

Application of the Improved PO Technique for Analysis of Scattering Problems

The major drawback of the physical optics (PO) approximation to the solution of scattering problems is that the edge effects can not be taken into account. Therefore, the PO-derived current should be usually corrected by including additional terms that account for diffraction phenomena. In this paper, the effect of the correction terms associated with diffraction on edges of a flat polygonal scatterer, and corresponding to the wedge diffraction is examined. Selected numerical examples demonstrate usefulness and limitations of the approach for analysis of the scattering problems.

Improving accuracy of FDTD modelling in biological applications

This contribution demonstrates a possibility of improving accuracy of the continuous wave steady-state FDTD prediction of the EM field and the specific absorption rate (SAR) distributions in the layered biological tissues by reducing the numerical dispersion error via appropriate direct modification of the constitutive parameters of the tissues. The attractiveness of the approach lies in that the enhanced accuracy of the FDTD prediction is obtained at the negligible cost of a trivial pre-processing of the material parameters.

Accelerating frequency-domain simulations using small shared-memory CPU/GPU cluster

Numerical approach to frequency response problems usually requires that the system governing equation is solved repeatedly at many frequencies. The computational efficiency of the overall process can be increased by departing from traditional sequential computing model in favor of utilizing the parallel processing capability commonly offered by modern hardware. In this paper, we consider a hybrid programming pattern, OpenMP + CUDA, from the perspective of a user of a rather typical low-cost multi-core CPU-based workstation that can accommodate up to four GPUs. Such the small-scale heterogeneous platforms have recently gained wide popularity in scientific computing as an inexpensive massively parallel architecture. The relevant programming model issues and performance questions are addressed. Experimental results for the example physics problem, that is, the electromagnetic scattering from perfectly electrically conducting body, show that significant performance improvement can be attained with the OpenMP + CUDA programming model.

On the convergence of adaptive bisectional frequency sampling technique combined with Stöer-Bulirsch algorithm

A simple adaptive frequency sampling scheme employing interval bisection combined with the Cauchy method implemented through Stöer-Bulirsch algorithm is examined as a tool for interpolating wideband system responses from numerical electromagnetic (EM) simulation. Emphasis is placed on examining the convergence of the method. Numerical experiments show that reliable interpolation can be done at substantially reduced computational effort compared to that of conventional uniform sampling. The relevant procedures can be easily interfaced with existing EM simulators.

GPU-accelerated MoM-based broadband simulations using Stoer-Bulirsch algorithm

This communication introduces a CUDA-enabled GPU accelerated technique for broadband analysis of arbitrary 3D conducting body-wire radiating/scattering structure. The solution is based on the integral equation dis-cretized by the method of moments (MoM) with the use of RWG-type basis functions. Wide-band data are generated from MoM simulation employing an adaptive frequency sampling of the observed quantity, and supported by implicit rational macromodelling via Stoer-Bulirsch algorithm. Numerical results are given for a helical antenna with a cylindrical cup reflector. The GPU-CUDA offers a speedup ratio nearly 9× over the CPU implementation.