As a numerical algorithm, the finite-difference time domain (fdtd) is effective in solving electromagnetic scattering problem of medium with high complexity. The computional efficiency is low by the traditional centra...
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ISBN:
(数字)9781665458641
ISBN:
(纸本)9781665458641
As a numerical algorithm, the finite-difference time domain (fdtd) is effective in solving electromagnetic scattering problem of medium with high complexity. The computional efficiency is low by the traditional central processing unit (CPU) platform. Therefore, the GPU-based fdtd method used to speed up its computational efficiency for bistatic RCS prediction of 3-D object is realized in this paper. Both the validation and efficiency of our implemen is verified by comparison of parallel result versus CPU's. A speedup of about 38x is realized on two NVIDIA K40 GPUs, which improves the computational efficiency. The results also show that the computional efficiency of the parallel method is related to the number of Yee cells.
The role of electromagnetic properties in the properties of meta materials is very important, but there is a problem of inaccurate evaluation of results. The light transformation theory cannot solve the problem of ele...
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In this paper. a modified fdtd algorithm is applied to analyze various anisotropic planar circuits in multilayer configuration via a new formulation of updated equations. This formulation takes into account the bianis...
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ISBN:
(纸本)9781728140643
In this paper. a modified fdtd algorithm is applied to analyze various anisotropic planar circuits in multilayer configuration via a new formulation of updated equations. This formulation takes into account the bianisotropic character of the substrate. For the first time, the effect of anisotropy on the cutoff frequency and bandwidth of rectangular waveguide is investigated as well as shielding effect on S parameters. Moreover, a new mesh function is proposed to reduce the CPU time. The computed results were compared to available data in literature and simulated results and a good agreement was observed.
In this study, finite-difference time-domain (fdtd) algorithm has been used to work out the cell light scattering problem. Before beginning to do the simulation contrast, finding out the changes or the differences bet...
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ISBN:
(数字)9781510609921
ISBN:
(纸本)9781510609914;9781510609921
In this study, finite-difference time-domain (fdtd) algorithm has been used to work out the cell light scattering problem. Before beginning to do the simulation contrast, finding out the changes or the differences between normal cells and abnormal cells which may be cancerous or maldevelopment is necessary. The preparation of simulation are building up the simple cell model of cell which consists of organelles, nucleus and cytoplasm and setting up the suitable precision of mesh. Meanwhile, setting up the total field scattering field source as the excitation source and far field projection analysis group is also important. Every step need to be explained by the principles of mathematic such as the numerical dispersion, perfect matched layer boundary condition and near-far field extrapolation. The consequences of simulation indicated that the position of nucleus changed will increase the back scattering intensity and the significant difference on the peak value of scattering intensity may result from the changes of the size of cytoplasm. The study may help us find out the regulations based on the simulation consequences and the regulations can be meaningful for early diagnosis of cancers.
This study assesses the shielding efficacy of local electromagnetic shield for the thyroid gland. The investigation employed a mechanical model of a thyroid shield gear, integrating it within a high-resolution three-d...
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This study assesses the shielding efficacy of local electromagnetic shield for the thyroid gland. The investigation employed a mechanical model of a thyroid shield gear, integrating it within a high-resolution three-dimensional virtual model (Duke). The simulation environment and biological electromagnetic model were constructed from 1 to 6 GHz, with the Finite-Difference Time-Domain (fdtd) algorithm. The results indicated that the specific absorption rate (SAR) values of the thyroid were significantly elevated under forward irradiation and in the L band (1-2 GHz). In addition, the local electromagnetic shield reduced the SAR values at the thyroid position, with a shielding efficiency ranging from 15 to 40 dB across the evaluated frequency range. Further, the local shielding effectiveness of the thyroid have obvious variety between frequency and polarization. However, the data also indicated a potential increase in SAR values in other tissues, notably the eyes by up to 4 dB. The study determines that local electromagnetic shields markedly reduce radiofrequency radiation to the thyroid, necessitating a balanced design approach that accounts for both protective benefits and side effects on other tissues. The method and result provide a new perspective and quantitative data for thyroid protection, which has important guiding significance for the design and practical application of electromagnetic protection products.
This research aims to contribute significantly to the field of plasmonic filtering technology within modern optical communication systems. By focusing on the development of a high-performance, more compact, and effici...
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This research aims to contribute significantly to the field of plasmonic filtering technology within modern optical communication systems. By focusing on the development of a high-performance, more compact, and efficient design, this study explores the potential of hybrid plasmonic filters to revolutionize optical filtering applications. The approach leverages an innovative active material with electrically tunable permittivity, allowing for dynamic control over the filter's optical properties. The research specifically examines four types of filters: low-pass filters (LPF), high-pass filters (HPF), band-pass filters (BPF), and band-reject filters (BRF). These filters are designed to operate effectively across a broad wavelength range of 1200-1800 nm, achieving a transmittance exceeding 98% at the output port, while maintaining isolation with transmittance below 2% at the isolated ports. The structure demonstrates a FWHM of approximately 216 nm for the band-pass filter and approximately 223 nm for the band-reject filter, which are considered moderate values, ensuring the versatility and multifunctionality of the design. The ultra-compact size, with a footprint of just 21 mu m2, makes these filters particularly advantageous for integration into space-constrained optical communication systems.
In this letter, an explicit and absolutely stable finite-difference time-domain (fdtd) algorithm is designed for electromagnetic analysis. The algorithm works through a structure composed of several vectors and matric...
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In this letter, an explicit and absolutely stable finite-difference time-domain (fdtd) algorithm is designed for electromagnetic analysis. The algorithm works through a structure composed of several vectors and matrices acting on these vectors. Excitation source is linearly approximated in a time interval, fields in the computation domain are expressed by a vector, and these matrices are derived based on the fdtd method. The proposed algorithm solves electromagnetic problems in an explicit way, its time step size is beyond the Courant-Friedrich-Levy (CFL) stability condition and the computation efficiency of the proposed method is also higher than the conventional fdtd method. Two numerical examples are tested and validate that the proposed algorithm can solve electromagnetic problems correctly and also improves calculation efficiency.
A new plasmonic metal-insulator-metal (MIM) band pass filter has been proposed. This paper has shown some advantages of this novel design, which includes circular air holes, and works in a longer wavelength as well as...
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ISBN:
(纸本)9781665433655
A new plasmonic metal-insulator-metal (MIM) band pass filter has been proposed. This paper has shown some advantages of this novel design, which includes circular air holes, and works in a longer wavelength as well as is sensitive to the size parameters of circular air holes and the resonator. The proposed structure has a multiple-mode with two resonance wavelengths;each of them has reached an acceptable transmission peak and a higher-quality factor than the previous structures. The main advantages of this plasmonic filter combined with air holes are to present a dual-mode filter with a sharp transmission in the wavelength range from 700 to 2000 nm. The size of the geometrical parameters in this structure will be adjusted in order to successfully achieve this aim. Subsequently, the characteristics of the proposed novel filter will be improved. The proposed structure has been investigated numerically utilizing the finite difference time domain (fdtd) method and the Drude model has been used for the modeling of the metal in the structure. Our device produces the maximum quality factor (Q-Factor) as well as the minimum FWHM by the values of 62.79 and 13.13, respectively. Also, the bandwidth of the structure is smaller than the previous structures. Moreover, a higher peak of transmittance (T-max) is 70% and the longer resonance wavelength is obtained at 1754 nm. This device is a good candidate for filtering applications which is used in optical circuits.
The optical switch is a crucial component in optical communications that plays an important role in transmitting the optical signal within a photonic circuit. In this paper, an all-optical plasmonic switch composed of...
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ISBN:
(纸本)9781728172965
The optical switch is a crucial component in optical communications that plays an important role in transmitting the optical signal within a photonic circuit. In this paper, an all-optical plasmonic switch composed of five nanodisks made from gold, planted inside SiO2 substrate, based on Fano resonance, has been proposed. The simulation results disclose that the structure can work as an infrared optical switch by adjusting the pump light at 825 nm wavelength. The occurrence of the second Fano resonance (FR) due to the reduction in the distance between nanodisks was reviewed. The two-dimensional simulations using the finite-difference time-domain algorithm are utilized to reveal apparent optical bistability and notable switching mechanism of the signal light. The results show -4.00 dB and -36.84 dB transmissions when the pump is OFF and ON, respectively. As known, in highly integrated optical communication, ultrasmall all-optical switches are of great importance. This switch has a nanoscale size of 450 nmx450 nm.
This paper, based on plasma generalized Zakharov model in ionosphere, studies the non-uniform nested grid in fdtd algorithm under plasma background. It is used to improve the fdtd algorithm for studying the nonlinear ...
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ISBN:
(纸本)9781538673027
This paper, based on plasma generalized Zakharov model in ionosphere, studies the non-uniform nested grid in fdtd algorithm under plasma background. It is used to improve the fdtd algorithm for studying the nonlinear process of the ionospheric Langmuir disturbance. A non-uniform nested grid method which can reduce the computational complexity of explicit fdtd algorithm while guaranteeing the computational accuracy is studied. A non-uniform nested grid fdtd method for calculating electromagnetic problems involving different orders of magnitude is proposed. Finally, the correctness and superiority of the non-uniform nested grid are verified by simulating the electromagnetic field distribution and propagation characteristics of the ionospheric Langmuir disturbance.
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