Transmission Line Matrix Research Articles

Compact model to efficiently characterize TSV-to-transistor noise coupling in 3D ICs

A methodology is proposed to characterize through silicon via (TSV) induced noise coupling in three-dimensional (3D) integrated circuits. Different substrate biasing schemes (such as a single substrate contact versus regularly placed substrate contacts) and TSV fabrication methods (such as via-first and via-last) are considered. A compact π model is proposed to efficiently estimate the coupling noise at a victim transistor. Each admittance within the compact model is approximated with a closed-form expression consisting of logarithmic functions. The methodology is validated using the 3D transmission line matrix (TLM) method, demonstrating, on average, 4.8% error. The compact model and the closed-form expressions are utilized to better understand TSV induced noise as a function of multiple parameters such as TSV type, placement of substrate contacts, signal slew rate and voltage swing. The effect of differential TSV signaling is also investigated. Design guidelines are developed based on these results.

Modeling Thermal Radiation Effects in Nanowires Using the TLM Method

In this paper, the use of the transmission line matrix (TLM) method for the treatment of thermal effects in nanoscale systems is discussed. A new approach is presented, which combines the modeling of thermal diffusion and radiation effects using emissivity in a 1-D TLM model. This paper shows the suitability of using the TLM to model the heat dissipation in nanoscale engineering components. It offers an appropriate solver for thermal applications, such as heat dissipation, in nanodevices. Two types of nanowires are simulated to demonstrate the behavior of the proposed approach.

Novel CDRC-TLM algorithm for the analysis of magnetized plasma

This paper presents a novel approach to model the interaction of electromagnetic waves with the magnetized plasma medium based on the Transmission Line Matrix (TLM) method. Anisotropic and dispersive characters of magnetized plasma are modeled by voltage sources, where the formulation is developed using the Current Density Recursive Convolution (CDRC) technique. Computational examples illustrate not only the improved accuracy, but also significant CPU time saving in comparison with TLM Constant Recursive Convolution (CRC-TLM) approach.

The segmentation concept for frequency-domain TLM method combined to the variable mesh technique

In this paper, the segmentation method is implemented in the frequency-domain transmission line matrix (FD-TLM). The method is combined with the variable mesh technique. Although the procedure is general, the examples shown concern the design of waveguide discontinuities. Thus, the structure is decomposed into several sub-domains and a finer mesh is used in the computational domain around discontinuities. An important reduction in computing time and memory resources is achieved with a good accuracy.

전달선로행렬 모델링에 의한 수중물체의 이동 시뮬레이션 방법에 대한 연구

We do research on the simulation of Doppler effect from a target`s moving under the sea by Transmission Line Matrix modeling which is one of numerical methods on time domain. To implement the effect, the input signal was entered at a moving node according to a moving target`s moving speed. The result had maximum 2.47% error compared with the theoretical value. And from simulation results with speed control of a moving target, we could also obtain resonable results within 0.63% error range.

Application of the transmission line matrix method for outdoor sound propagation modelling – Part 1: Model presentation and evaluation

The present paper deals with an original time-domain approach applied to outdoor sound propagation under meteorological effects. The transmission line matrix method, based on the Huygens’ principle, had already been validated over impedant grounds and complex topography. The presented formulation proposes to take into account meteorological effects (wind speed and temperature) through the relative sound speed. The necessary wavefront direction is determined through the calculation of the averaged intensity vector direction. A good agreement is found between simulations of both the transmission line matrix and parabolic equation methods. A relevant use of the method is shown in the framework of environmental acoustics and initial applications are proposed in Part 2.

Application of the Transmission Line Matrix method for outdoor sound propagation modelling – Part 2: Experimental validation using meteorological data derived from the meso-scale model Meso-NH

Outdoor sound prediction is both a societal concern and a scientific issue. This paper deals with numerical simulations of micrometeorological (temperature and wind) fields for environmental acoustics. These simulations are carried out using the reference meso-scale meteorological model at the Meteo-France weather agency (Meso-NH). Meso-NH predictions at very fine scales (up to 3m), including new developments (drag force approach), are validated both numerically and experimentally under stable, unstable and neutral conditions. Then, this information can be used as input data for the acoustic propagation model. The time-domain acoustic model is based on the Transmission Line Matrix method. Its development has also been promoted for application to outdoor sound propagation, i.e. to take into account topography, ground impedance, meteorological conditions, etc. In part 1, the presentation and evaluation of the Transmission Line Matrix method showed the relevance of this method’s use in the context of environmental acoustics. Finally, simulated noise levels under different propagation conditions were compared to in situ measurements. Satisfactory results were obtained regarding the variability of the observed phenomena.

A simple absorbing layer implementation for transmission line matrix modeling

An absorbing layer formulation for transmission line matrix modeling is proposed. The approach consists in attenuating the incident pulse propagating toward the absorbing layer only, using an attenuation factor which gradually decreases as the sound wave propagates along the absorbing medium. The formulation of the damping function followed by the attenuation factor along the absorbing layer is depicted and discussed. The efficiency of the present formulation is validated by comparison with another absorbing layer model and virtual boundary conditions proposed in the literature. Numerical simulations are also given in order to evaluate the effects of both the attenuation factor and the depth on the absorbing layer efficiency. As expected, results are consistent with absorbing layer implementation in other numerical methods; firstly, the attenuation at the entrance of the absorbing layer must be gentle, and secondly the efficiency increases with the layer depth. Lastly, it is shown that the unwanted reflection seems to vanish over the time when increasing the layer depth, meaning that reflections continuously occur within the absorbing layer and not on the geometrical limits of the absorbing layer. Although the approach is dedicated to outdoor sound propagation modeling (only an example on urban acoustics application is given), the proposed formulation of absorbing layers can be applied in other domains of acoustics. However, its application in shielded areas should be avoided because unwanted reflections due to an insufficient attenuation can be significant in comparison with the ambient noise in such quiet environments.

Computationally Efficient MR-FDPF and MR-FDTLM Methods for Multifrequency Simulations

We propose a modification of the multi-resolution frequency domain ParFlow (MR-FDPF) method that allows simulating radio propagation channels in a frequency range. The performance of the proposed MR-FDPF implementation has been analyzed based on different realistic propagation scenarios. We also analyze the possibility of applying the multi-resolution frequency domain approach to the well-known transmission-line matrix method. The proposed multi-resolution frequency domain transmission-line matrix method provides a computationally efficient way of modeling radio wave propagation in three-dimensional space at multiple frequencies.

Absorbing boundary conditions for the FD-TLM method : the perfectly matched layer and the one-way equation technique

This paper investigates the absorbing boundary conditions for the frequency domain transmission line matrix method. Two approaches are presented, namely the perfectly matched layer (PML) technique and the one-way wave equation. Concerning the PML technique, two-dimensional and three-dimensional transmission line matrix (TLM) nodes, already used in time domain, are exploited in frequency domain where a rigorous formulation of these PML-TLM nodes is presented. In addition, two types of one-way wave operators are also transposed from time to frequency domain TLM approach: Taylor expansion and Higdon's boundary conditions. The simulation of a wideband matched load WR-28 rectangular waveguide is presented for validation. Excellent results are obtained with a very thin PML layer. Results concerning one-way operator techniques also show very good return loss performances. For instance, Higdon's boundary condition was extended beyond third-order approximation, and a return loss better than 160 dB was obtained. Copyright © 2013 John Wiley & Sons, Ltd.

Dispersive TLMZ-transform model of left-handed metamaterials

SUMMARY In this paper, a numerical model of electromagnetic left-handed metamaterials is proposed. The dispersive properties of these materials are accounted for in the time domain by using the transmission-line matrix method based on Z-transforms. The close agreements obtained between the analytic and numerical results verify the validity, accuracy and stability of the approach. Copyright © 2013 John Wiley & Sons, Ltd.

Cylindrical grid-based TLM model of a coaxially loaded cylindrical cavity

This paper explores the effectiveness of the Transmission–Line Matrix (TLM) method based on the cylindrical grid for the purpose of an analysis of a cavity with a circular cross–section and coaxial load. To consider the advantages of the cylindrical over rectangular TLM grid, coaxial inner load with different dielectric properties and dimensions have been used. Obtained numerical results have been verified comparing with corresponding analytic and measured results.

TLM modelling of receiving dipole antenna impact on shielding effectiveness of enclosure

Impact of receiving dipole antenna on shielding effectiveness of metallic enclosure is numerically considered in this paper. Transmission line matrix (TLM) method enhanced with compact wire model is used to efficiently describe the dipole antenna presence and its coupling with electromagnetic field inside enclosure. By using the presented numerical model, influence of receiving antenna on enclosure shielding effectiveness is demonstrated on several examples through comparison with the numerical and analytical approaches in which the antenna presence is neglected.

2D FDTLM HYBRIDIZATION WITH MODAL METHOD

This article focuses on the 2D hybrid technique between the Frequency Domain Transmission Line Matrix Method (FDTLM) and the Wave Concept Iterative Procedure (WCIP). 3D hybridization has already been studied, but results may be improved through a better knowledge of method order. Consequently, developing 2D hybridization aims at understanding the hybridization in simplest problems, especially because Transverse Electric (TE) and Transverse Magnetic (TM) are uncoupled. Our study dwells on accuracy and convergence order of the 2D hybrid method, which will help for 3D mesh use. In this perspective, the scattering nodes and electromagnetic flelds expressions are established in the 2D general case with anisotropic materials. As a result, validation examples are presented to check the approach.

ARBITRARY LOSS FACTORS IN THE WAVE PROPAGATION BETWEEN RHM AND LHM MEDIA WITH CONSTANT IMPEDANCE THROUGHOUT THE STRUCTURE

We investigate the wave propagation properties in lossy structures with graded permittivity and permeability involving left- handed metamaterials. An exact analytic solution to Helmholtz' equation for a lossy case with both real and imaginary parts of permittivity and permeability proflle, changing according to a hyperbolic tangent function along the direction of propagation, is obtained. It allows for difierent loss factors in RHM and LHM media. Thereafter, the corresponding numerical solution for the fleld intensity along the composite structure is obtained by means of a dispersive numerical model of lossy metamaterials that uses a transmission line matrix method based on Z-transforms. We present the expressions and graphical results for the fleld intensity along the composite structure and compare the analytic and numerical solutions, showing that there is an excellent agreement between them.

A Novel and Efficient Technique for Improving Shielding Effectiveness of a Rectangular Enclosure using Optimized Aperture Load

An efficient and practical method to enhance the shielding effectiveness of a rectangular enclosure with aperture against electromagnetic interferences is presented. In this paper an extra aperture as a matched load instead of a shorted waveguide has been proposed. Transmission line matrix method was used for simulation the rectangular enclosure under electromagnetic plane waves and the result was verified by analytical method and CST software. A complete range of simulations were performed to find the optimum size for second aperture. The proposed method resulted in a very good improving of shielding effectiveness of enclosure especially in resonant frequency.DOI: http://dx.doi.org/10.5755/j01.eee.18.10.3071

The Solution of Transient Electromagnetic Inverse Source Problems Using Time-Domain TLM Method

The electromagnetic inverse source problem (ISP) for homogeneous background medium is investigated numerically using the transmission-line matrix (TLM) method. By transforming all electromagnetic sources and fields into their equivalent link impulses within a TLM computational domain, a discrete linear inversion formulation is developed. Our formulation solves for the unknown source distribution inside a closed region using the knowledge of the near-field data on its boundary. Unlike the conventional frequency-domain treatments, both our source solution and the field measurements are in the time domain. The nonuniqueness of the ISP is addressed by additionally imposing smoothness constraints that minimize the first-order time and spatial derivatives of the source distribution. Our algorithm is illustrated through a number of numerical examples. It is also shown that our algorithm is robust against the noisy field measurements.

TIME DOMAIN ANALYSIS OF HELMHOLTZ SOLITON PROPAGATION USING THE TLM METHOD

The transmission line matrix method is used to study Helmholtz solitons as solutions of the two-dimensional time-domain Maxwell equations in nonlinear media. This approach permits to address, in particular, the propagation and intrinsic stability properties of subwavelength soliton solutions of the scalar nonlinear wave equation and the behavior of optical solitons at arbitrary interfaces. Various numerical issues related to the analysis of soliton beams using the time-domain method are also discussed.

전달선로행렬법을 이용한 흡음재 모델링에 대한 수치해석

본 연구에서는 해저의 반사면이나 흡음재와 같이 주파수에 따라 다른 특성을 가지는 매체를 시간영역에서 수치적으로 모델링하고자 시간 해석 기법의 하나인 전달선로행렬법을 이용하였다. 기존의 흡음재의 해석에 응용되던 감쇠를 이용하는 방법의 대안으로 유한임펄스응답 필터를 전달선로행렬법에 도입하였다. 7개의 탭을 가진 FIR 필터로 구현하였으며, 시간 지연, 저역통과필터, 고역통과필터의 시뮬레이션 결과를 이론치와 비교하였다. 여러 시뮬레이션 결과를 통해 흡음재의 주파수에 따른 흡음 특성을 유한임펄스응답 필터를 고려한 하나의 요소만으로 모델링하는 것이 가능하다는 것을 확인할 수 있었다. We introduced an approach of modeling of a sound absorbing medium that had different absorbing coefficient according to frequency. To obtain the time domain result of the frequency characteristics of a sound absorbing medium, transmission line matrix modeling was used. To input sound absorbing effect in TLM modeling, we added a FIR filter at a node instead of absorbing component using resistance component. There were simulated the characteristics of time-shift, low pass filter, high pass filter using the FIR filter with 7-tap coefficients, then compared with theoretical results. From various simulation results, we could find that added FIR filter coefficient in TLM modeling was an useful way to model a sound absorbing medium.

TLM Extension to Electromagnetic Field Analysis of Anisotropic and Dispersive Media: A Unified Field Equation

The transmission-line matrix (TLM) method, in time domain, is extended to account for the presence of anisotropic and dispersive media in electromagnetic structures or devices. The model is thoroughly constructed by using Maxwell's equations that make it a unified general TLM formulation. Numerical results are compared with experimental measurements; hence, in the case of ferrite-based structures, validating the model and showing the accuracy of the approach.