Numerical technique for wireless communication system with high speed movement

Numerical technique for the analysis of EM field with high speed moving dielectric body by using FDTD method with Overset Grid Generation method considering Lorentz transformation is presented. The characteristic of EM field when incident wave hits the moving dielectric body with high velocity value are analyzed. The accuracy of the proposed technique is validated. Good agreements are obtained between numerical results and theoretical results. The development of this numerical technique will give a great impact for many areas, particularly for the future high speed mobile communication systems used in transportation and aerial radar systems to detect the high speed motion of a moving boundar

Numerical analysis of the EM field from a moving source and the application for a moving vehicle

Many practical engineering applications require the numerical solution for the analysis of the EM field by a moving source and/or a moving body. We have previously proposed the Overset Grid Generation method coupled with FDTD method for the analysis of the EM field with moving boundaries considering Doppler Effect. By overlapping one moving sub-mesh on a static main mesh, each mesh is calculated alternately by using interpolation technique. For higher velocity value, Lorentz transformation is applied to the FDTD method. In this paper, after verifying the accuracy of this technique, it is applied for the EM field at an intersection when the input source is moving towards the moving vehicle

FDTD method for the analysis of the EM field from a moving source

A numerical technique for the analysis of the EM field by a moving source or a moving body can be significantly important for the realization of new optical/nanotechnology devices. We have previously proposed the Overset Grid Generation method coupled with FDTD method for the analysis of the EM field with moving boundaries considering Doppler Effect. By overlapping one moving sub-mesh on a static main mesh, each mesh is calculated alternately by using interpolation technique. For higher velocity value, Lorentz transformation is applied to the FDTD method. In this paper, this technique is proposed for solving the EM field when the input source is moving. As a bench mark, the received wave at the observation point is calculated when the source moves for x-direction in free space intersect at right angle by the dielectric object. The numerical results are compared with the stationary case and the moving case

A Numerical Approach to the Efficient Analysis of2D RF-MEMS Capacitor with Accelerated Motion

The advancement in new numerical technique is the key to success of newer generation RF MEMS devices. In this paper, a novel time-domain modeling technique that has the capability to accurately simulate the transient effect of RF MEMS variable capacitors with accelerated motion controlled by the coupling of the electrostatic and mechanical forces is presented. The relation between the sinusoidal modulations of the frequency with the acceleration is shown. Its validity has been demonstrated in comparison between the computational results of the displacement with the theoretical results. Both results are in very good agreement. The next work will be considered to include the damping coefficient. Due to its numerical efficiency, the proposed technique can be a useful technique, which makes it suitable for the numerical analysis of the moving boundary problem in the near futur

An Efficient of Overlapping Grid Method with Scattering Technique in Time Domain for Numerical Modeling

An Overlapping Grid Method (OGM) with Biquadratic Spline Interpolation in scattering technique was developed to solve the direct and inverse scattering issues. A two-dimensional (2D) numerical image model was used to analyze the accuracy of the proposed method in a direct scattering process. It was discovered that when the sub-grid, s ∆x increased, the absolute error for the electric field amplitude will also increase. The results also discovered that as the grid size ratio increased, the absolute error of the amplitude EZ will also increase. The findings show that smaller grid spacing and a finer grid size can produce more accurate results. The Overlapping Grid Method (OGM) with Biquadratic Spline Interpolation was expanded by incorporating with Forward-Backward Time Stepping (FBTS) technique to solve inverse scattering issues. Homogenous embedded objects with a square and circular shape are used to validate the efficiency of the proposed method. The findings showed that the proposed numerical method could detect and reconstruct embedded objects in different shapes. The efficiency of the proposed method was examined by Mean Square Error (MSE) and normalizing the functional error. The findings revealed that the MSE of dielectric profiles for the proposed method were lower than the FDTD method in FBTS. The relative permittivity and conductivity profile differed by 27.06% and 20%, respectively. Hence, it was proven that the proposed method successfully solved a known drawback to the FDTD method and produced more accurate and efficient results

A New Approach for Solving Inverse Scattering Problems with Overset Grid Generation Method

This paper presents a new approach of Forward-Backward Time-Stepping (FBTS) utilizing Finite-Difference Time-Domain (FDTD) method with Overset Grid Generation (OGG) method to solve the inverse scattering problems for electromagnetic (EM) waves. The proposed FDTD method is combined with OGG method to reduce the geometrically complex problem to a simple set of grids. The grids can be modified easily without the need to regenerate the grid system, thus, it provide an efficient approach to integrate with the FBTS technique. Here, the characteristics of the EM waves are analyzed. For the research mentioned in this paper, the ‘measured’ signals are syntactic data generated by FDTD simulations. While the ‘simulated’ signals are the calculated data. The accuracy of the proposed approach is validated. Good agreements are obtained between simulation data and measured data. The proposed approach has the potential to provide useful quantitative information of the unknown object particularly for shape reconstruction, object detection and others

An efficient of overlapping grid method with scattering technique in time domain for numerical modeling

An Overlapping Grid Method (OGM) with Biquadratic Spline Interpolation in scattering technique was developed to solve the direct and inverse scattering issues. A two-dimensional (2D) numerical image model was used to analyze the accuracy of the proposed method in a direct scattering process. It was discovered that when the sub-grid, sxΔ increased, the absolute error for the electric field amplitude will also increase. The results also discovered that as the grid size ratio increased, the absolute error of the amplitude ZE will also increase. The findings show that smaller grid spacing and a finer grid size can produce more accurate results. The Overlapping Grid Method (OGM) with Biquadratic Spline Interpolation was expanded by incorporating with Forward-Backward Time Stepping (FBTS) technique to solve inverse scattering issues. Homogenous embedded objects with a square and circular shape are used to validate the efficiency of the proposed method. The findings showed that the proposed numerical method could detect and reconstruct embedded objects in different shapes. The efficiency of the proposed method was examined by Mean Square Error (MSE) and normalizing the functional error. The findings revealed that the MSE of dielectric profiles for the proposed method were lower than the FDTD method in FBTS. The relative permittivity and conductivity profile differed by 27.06% and 20%, respectively. Hence, it was proven that the proposed method successfully solved a known drawback to the FDTD method and produced more accurate and efficient results

B2-Spline Interpolation Technique for Overset Grid Generation and Finite-Difference Time-Domain Method

—In this paper, B2-spline interpolation technique for Overset Grid Generation and FiniteDifference Time-Domain (OGG-FDTD) method was developed. B2-spline or biquadratic spline interpolation offers better accuracy than bilinear interpolation. Two-dimensional (2D) numerical simulations were carried out for electromagnetic (EM) field analysis to measure the scattered fields for an unknown object in free space and dielectric medium. In this work, two antennas were utilised as transmitter and receiver sequentially to transmit microwave pulses and collect the scattered fields for an unknown object in OGG-FDTD lattice. In order to analyse the stability and efficiency of the proposed method, the scattered fields for the unknown object were investigated with error analysis. The results showed that the OGG-FDTD method with B2-spline interpolation gave lower relative error than bilinear interpolation with 0.0009% of difference in free space, 0.0033% of difference in Case A dielectric medium, 0.236% of difference in Case B dielectric medium, and 0.003% of difference in Case C dielectric medium. Besides, the Mean Square Error (MSE) for the OGG-FDTD method with B2-spline interpolation was also lower than the bilinear interpolation. Hence, it proves that the OGG-FDTD method with B2-spline interpolation has the ability to measure the scattered fields around an unknown object accurately. For future work, the proposed method can be applied to inverse scattering to detect and reconstruct buried objects with arbitrary shapes in a complex media

A new approach for solving inverse scattering problems with overset grid generation method

This paper presents a new approach of Forward-Backward Time-Stepping (FBTS) utilizing Finite-Difference Time-Domain (FDTD) method with Overset Grid Generation (OGG) method to solve the inverse scattering problems for electromagnetic (EM) waves. The proposed FDTD method is combined with OGG method to reduce the geometrically complex problem to a simple set of grids. The grids can be modified easily without the need to regenerate the grid system, thus, it provide an efficient approach to integrate with the FBTS technique. Here, the characteristics of the EM waves are analyzed. For the research mentioned in this paper, the 'measured' signals are syntactic data generated by FDTD simulations. While the 'simulated' signals are the calculated data. The accuracy of the proposed approach is validated. Good agreements are obtained between simulation data and measured data. The proposed approach has the potential to provide useful quantitative information of the unknown object particularly for shape reconstruction, object detection and others. © 2017 Universitas Ahmad Dahlan