Three-dimensional Transmission Line Matrix Research Articles

Efficient 3D-TLM Modeling and Simulation for the Thermal Management of Microwave AlGaN/GaN HEMT Used in High Power Amplifiers SSPA

A three-dimensional thermal simulation investigation for the thermal management of GaN-on-SiC monolithic microwave integrated circuits (MMICs) of consisting multi-fingers (HEMTs) is presented. The purpose of this work is to demonstrate the utility and efficiency of the three-dimensional Transmission Line Matrix method (3D-TLM) in a thermal analysis of high power AlGaN/GaN heterostructures single gate and multi-fingers HEMT SSPA (solid state power amplifiers). The self-heating effects induce thermal cross-talk between individual fingers in multi-finger AlGaN/GaN that affect device performance and reliability. Gate-finger temperature differences only arise after a transient state, due to the beginning of thermal crosstalk which is attributed to the finite rate of heat diffusion between gate fingers. The TLM method accounts for the real geometrical structure and the non-linear thermal conductivities of GaN and SiC in order to improve the realistic calculations accuracy heat dissipation and thermal behavior of the device. In addition, two types of heat sources located on the top of GaN layer are considered in thermal simulations: Nano-scale hotspot as a pulsed wave heat source under gate and micro-scale hotspot as a continuous wave heat source, between gate and drain. Heat diffusion however, occurs not only between individual gate fingers (inter-finger) in a multi-finger HEMT, but also within each gate finger (intra-finger). To compare results, a Micro-Raman Spectroscopy experience is conducted to obtain a detailed and accurate temperature distribution. Good agreement between the microscopic spectral measurement and TLM simulation results is observed by accepting an error less than 2.2% relative to a maximum temperature. Results show that the 3D-TLM method is suitable for understanding heat management in particular for microwave devices AlGaN/GaN HEMTs SSPA amplifier. TLM method helps to select and locates the expected hot spots and to highlight the need of thermal study pre-design in order to minimize the system-level thermal dissipation and lead therefore to higher reliability.

An Accurate and Fast Substrate Noise Prediction Method With Octagonal TSV Model for 3-D ICs

In this paper, a refined equivalent circuit model considering semiconductor effect of 3-D ICs is proposed based on three-dimensional transmission line matrix method. In the proposed model, the depletion region around a through silicon via (TSV) is modeled as distributed voltage-dependent capacitors and resistors. With the proposed model, noise behaviors could be accurately obtained under relatively short simulation time when compared to the time needed by full wave simulators. The simulation result of the proposed model is aligned with both ANSYS HFSS and TCAD Sentaurus in frequency and time domains while the simulation time is greatly reduced to less than 1%. The influence of TSV-induced substrate noise on an active circuit is demonstrated using the proposed model. The CMOS inverter affected by the noisy substrate shows up to 34-mV deviation at the inverter output when compared to the inverter on a noise-free substrate.

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.

TLM modeling of a probe-coupled cylindrical cavity based on compact wire model in the cylindrical mesh

This article describes an implementation of a compact wire model into the three-dimensional transmission-line matrix (TLM) cylindrical mesh for the purpose of an efficient analysis of probe-coupled cylindrical microwave cavity devices. Because of a cylindrical grid structure and empirical nature of the compact model, this implementation has to take into account a change of wire model parameters with a variable cross section of the TLM nodes through which a wire conductor passes. The model accuracy has been experimentally verified and compared with the corresponding results reached by the TLM method based on a rectangular grid in order to consider its advantages. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012. © 2012 Wiley Periodicals, Inc.

Modeling and Analysis of Through-Silicon Via (TSV) Noise Coupling and Suppression Using a Guard Ring

In three-dimensional integrated circuit (3D-IC) systems that use through-silicon via (TSV) technology, a significant design consideration is the coupling noise to or from a TSV. It is important to estimate the TSV noise transfer function and manage the noise-tolerance budget in the design of a reliable 3D-IC system. In this paper, a TSV noise coupling model is proposed based on a three-dimensional transmission line matrix method (3D-TLM). Using the proposed TSV noise coupling model, the noise transfer functions from TSV to TSV and TSV to the active circuit can be precisely estimated in complicated 3D structures, including TSVs, active circuits, and shielding structures such as guard rings. To validate the proposed model, a test vehicle was fabricated using the Hynix via-last TSV process. The proposed model was successfully verified by frequency- and time-domain measurements. Additionally, a noise isolation technique in 3D-IC using a guard ring structure is proposed. The proposed noise isolation technique was also experimentally demonstrated; it provided -17 dB and -10dB of noise isolation between the TSV and an active circuit at 100 MHz and 1 GHz, respectively.

TLM method for thermal investigation of IGBT modules in PWM mode

The insulated gate bipolar transistor (IGBT) is popularly used in high power, high frequency power-electronic applications such as motor control and inverters. These applications require well designed thermal management system to ensure the protection of IGBTs. Choice simulation tools for accurate prediction of device power dissipation and junction temperature become important in achieving optimised designs. In this paper, thermal analysis of a 1200 A, 3.3 kV IGBT module was investigated and analysed using the three-dimensional transmission line matrix (3D-TLM) method. The results show a three-dimensional visualisation of self-heating phenomena in the device. Since the comparison TLM results with the analytical solutions do not exist for this IGBT module, we use the MSC.NASTRAN tool to find the similar range of the temperatures. Results are compared. Typically, IGBT is used in a three-phase inverter leg where the control signals are generated via PWM scheme so, the prediction of the temperature rise is important in the pulse operation conditions for the IGBT device. A view of the dynamic thermal temperature rise is obtained with 100 W-step pulse dissipation applied at IGBT chips. The temperature rises are calculated using TLM method during the PWM load cycles. Simulations give clear indications of the importance of the spreader material and are helpful in selecting the proper one. TLM has been successful in modelling heat diffusion problems and has proven to be efficient in terms of stability and complex geometry. The three-dimensional results show that method has a considerable potential in power devices thermal analysis and design.

Experimental analysis and modelling of textile transmission line for wearable applications

PurposeThe paper seeks, by means of measurement and modelling, to evaluate frequency dependent per‐unit‐length parameters of conductive textile transmission line (CTTL) for wearable applications and to study deterioration of these parameters when CTTL is subjected to washing.Design/methodology/approachThe studied transmission line is made of Nickel/Copper (Ni/Cu) plated polyester ripstop fabric and is subjected to standard 60°C cycle in a commercial off‐the‐shelf washing machine. The per‐unit‐length parameters (resistance and inductance) and characteristic impedance of the line are extracted from measurements before and after washing. Using the measurement data an equivalent circuit is created to model the degradation of the line. The circuit is then integrated in a three‐dimensional transmission line matrix (TLM) model of the transmission line.FindingsBoth an electrical equivalent circuit and a TLM model are developed describing the degradation of the conductive textile when washed. A severe deterioration of the electrical parameters of the line is noticed. Experimental and modelling results are in good agreement in the addressed frequency band.Research limitations/implicationsAnalysis is performed for frequencies up to 10 MHz. The developed TLM model can be used to conduct parametric studies of the CTTL. To counteract the degradation of the line, protective coating is to be considered in further studies.Originality/valueThis paper extends knowledge of the subject by experimental and simulation‐based characterization of the CTTL when subjected to washing cycles.

Experimental investigations and three-dimensional transmission line matrix simulation of Ca5−xAxB2TiO12 (A=Mg, Zn, Ni, and Co; B=Nb and Ta) ceramic resonators

Temperature-stable, low-loss Ca5−xAxB2TiO12 (A=Mg, Zn, Ni, and Co; B=Nb and Ta) dielectrics suitable for microwave telecommunication applications were prepared by the conventional solid-state ceramic route. Investigations were made on the structure and microstructure of the ceramics employing x-ray and scanning electron microscopic techniques. The dielectric properties were measured in the 3.5–7GHz frequency range. The time domain simulation of electromagnetic wave interaction with dielectric materials, using three-dimensional transmission line matrix modeling methods, is presented. Excellent agreement between experimental and simulated values of microwave dielectric properties was observed. The materials are potential candidates for applications in filters, oscillators and high efficiency low-loss dielectric antennas working especially at millimeter wave region.

Transmission Line Matrix Model for Detection of Local Changes in Permeability Using a Microwave Technique

A three-dimensional transmission-line matrix model was developed to simulate the microwave detection of local changes in permeability. The technique can be used to map local nonuniformities in magnetization. Numerical modeling was carried out for frequencies that are commonly used in microwave nondestructive testing (0.8-1 GHz). A comparison between experimental and numerically generated curves is provided. This comparison validated the proposed numerical model.

A three‐dimensional transmission line matrix (TLM) simulation method for thermal effects in high power insulated gate bipolar transistors

In this paper, thermal analysis for a 1,200 A, 3.3 kV insulated gate bipolar transistor (IGBT) module was investigated and analysed using the three‐dimensional transmission line matrix (3D‐TLM) method. This paper also reviews the present status of the use of various thermal heat spreaders such as AlSiC MMC, Cu‐Mo and graphite‐Cu MMC and compares these with copper based heat spreaders and the use of aluminium nitride (AlN), diamond and BeO as substrates and their effect to dissipate the heat flux in heat sources localised in IGBT module design. The TLM method was found to be a versatile tool which is ideally suited to the modelling of many power electronic devices and which proved very useful in the study of transient thermal effects in a variety of device structures.

A three-dimensional TLM simulation method for thermal effect in high power insulated gate bipolar transistors

The miniaturisation of electronic networks creates problems of heat dissipation. Good thermal management is therefore essential. Simulation of power electronic systems presents peculiar challenges due to the need of detailed modelling for both circuitry and control algorithms. Transmission Line Matrix method (TLM) is a powerful tool for analysing thermal effects in electronic circuits and high power devices. In this paper, thermal analysis for a 1200 A, 3.3 kV IGBT (Insulated Gate Bipolar Transistor) module has been announced at two levels, module and system level. For the module level analysis, the thermal of the IGBT module was investigated and analysed using the Three-Dimensional Transmission Line Matrix (3D-TLM) method. The results show a three-dimensional visualisation of self-heating phenomena in the device, including the effect of the use the Metal Matrix Composite (MMC) materials as base plate over conventional materials for electronic packaging thermal control and the use of the ceramics as substrate. This paper reviews the present status of the use of various thermal heat spreader such as Al SiC MMC, Cu–Mo and Graphite–Cu MMC and comparing those with copper-based heat spreader and the use of AlN, Diamond and Beo as substrates and their effect to dissipate the heat flux in heat sources localised in IGBT module design and taking into account effects of the geometry of the module, and specific material thickness because they play an important role in dissipating the generated heat and outweigh the thermal properties of the module. For the system level analysis, the total system that consists of the IGBT module and water-cooled heat sink is analysed suited to the modelling of many power electronics devices. The thermal simulations were run for various conditions and power levels including measurement and numerical results obtained by other simulators tools as MSC.PATRAN, FLOTHERM and LAASTHERM. Results are compared. The TLM method is found to be a versatile tool which is ideally suited to the modelling of many power electronic devices and proved very useful in the study of transient thermal effects in a variety of device structures.

Theoretical Comparison of TLM and Hybridization of MoM and GMT for the Numerical Analysis of the Electromagnetic Field Inside the Biological Bodies

The problem of determining electromagnetic fields (EMF), absorbed power density (APD), and specific absorption rate (SAR) inside arbitrarily shaped biological bodies is considered. The biological bodies are assumed as the human body or human brain illuminated by a plane wave, and EMF, APD, and SAR are calculated inside the biological bodies. The EMF, APD, and SAR theoretical derivation inside the biological bodies by a three-dimensional transmission line matrix (TLM) method with asymmetrical condensed node is given. The combination of the method of moment (MoM) and generalized multipole technique (GMT) is used to determine the field inside the biological bodies. A complete dispersion analysis is given for the TLM and combination of MoM and GMT. In TLM, wave amplitudes inside electric and magnetic field components represent the electromagnetic field. The correct mapping between the wave amplitudes and field components is described by the cell boundary mapping. The combination of MoM and GMT method is based on domain integral representation of the field inside the body. Both methods involve an iterative minimization of the defect between the number of cells and the field calculated by integral representation. The two algorithms are compared. The methods employed the same initial guess and a priori information that the characteristic function is nonnegative.

Optimization of the PML efficiency in 3-D TLM method

In this paper, the complete derivation of the new perfectly matched layer symmetrical condensed node (PML SCN) recently proposed for the implementation of the Berenger's PML's in the three-dimensional transmission-line matrix (TLM) method is given. Several comparisons between TLM and finite-difference time-domain experiments are performed in order to better understand the behavior of PML's in TLM simulations. In particular, the way to implement the numerical conductivity values with the PML SCN is considered. TLM simulations of waveguide and microstrip antennas are finally presented to prove that the use of this new PML SCN improves the absorbing boundary conditions in the TLM.

A three-dimensional transmission line matrix method (TLM) for simulations of logging tools

A three-dimensional (3-D) transmission line matrix method (TLM) in cylindrical coordinates for the simulation of logging tools is formulated and programmed. The radiation properties of a coil-type antenna in a conductive medium are analyzed and simulated with TLM formulations. The symmetrical condensed nodes (SCN) are adopted. This algorithm can be applied to both induction and measuring-while-drilling (MWD) tools in both the time and frequency domains, and the formation can be anisotropic. Perfectly matched layer (PML) absorbing boundary conditions are used to simulate an infinite boundary in real logging situations. Verifications and some examples are presented.

Matched absorbing medium techniques for full-wave tlm simulation of microwave and millimeter-wave components

This paper investigates the absorbing layer techniques for three-dimensional transmission-line matrix (3d-tlm) simulations. Applications are the full-wave analysis of structures such as microwave and millimeter-wave circuits open to free space. Two approaches are presented, namely the matched layer (ml) and the perfectly matched layer (pml) technique which is used for general cases. For the ml technique, which is efficient for matching guides operating in a quasi-TEM condition, a comparison of the different tlm condensed node is carried out. Concerning the more general case of the pml technique, the theoretical development of a new general three-dimensional (3d) tlm condensed cell is presented. Results pertaining to the characterization of planar circuits are compared with other solutions or measurements. It is found that a proposed unified approach, which includes the tlm simulation for matched layer media, yields very good performance in terms of the absorbing boundary condition (abc).

Absorbing-boundary conditions using perfectly matched-layer (PML) technique for three-dimensional TLM simulations

This paper describes the algorithm that interfaces the three-dimensional (3-D) transmission-line matrix (TLM) with an absorbing-boundary condition (ABC) based on the perfectly matched-layer (PML) approach. The algorithm uses a coupling between the TLM symmetrical condensed node (SCN) network and a finite-difference approximation of the PML equations. Examples are presented in scattering problems and S-parameter characterization of discontinuities. Excellent results are found even with absorbing walls located in the region of evanescent waves. Absorption performances obtained are significantly superior to ABC's based on the one-way equation approach and currently used for TLM simulations. Finally, it is found that for all tested situations, the algorithm is numerically stable.

The generalized TLM-based FDTD-summary of recent progress

The transmission-line-matrix (TLM)-based finite-difference time-domain (FDTD) method has been generalized recently to incorporate graded mesh and anisotropic media. The method is equivalent to the three-dimensional TLM symmetrical condensed node, but is formulated and computed in a FDTD fashion. Therefore, it retains certain features of both the TLM and FDTD methods. The authors report recent progress in modeling with the TLM-based FDTD method, namely, successful implementation of the perfectly matched layer (PML) and simulation of nonlinear wave propagation.

Antenna research at the Communications Research Centre

An overview is presented of the antenna research carried out by the Directorate of Antennas and Integrated Electronics (DAIE) of the Communications Research Centre (CRC). The antenna research within the DAIE can be categorized into two groups: antenna-hardware development and electromagnetic-software development. Research in antenna hardware has focused on printed multi-layer arrays, dielectric-resonator antennas, ferrite antennas, active-circuit integration, and low-loss feed networks. Research in electromagnetic software includes the development of three-dimensional transmission-line-matrix (TLM) code, and the application of cellular automata (CA) techniques for the analysis and modeling of antennas, microwave circuits, and general electromagnetic phenomena, such as scattering. This article concentrates on the antenna-hardware research and development within the DAIE. Radiation patterns are considered.

Application of the TLM method to half-space and remote-sensing problems

The problem of scattering and radiation in the presence of a material half-space is solved using the transmission line matrix (TLM) method. The TLM method is a general numerical method for obtaining an approximate solution to the time-dependent form of Maxwell's equations in the presence of complex environments. The method requires the discretization of the entire spatial domain of the problem and provides the transient response as well as (through discrete Fourier transform) the frequency domain response. The three-dimensional symmetric-condensed TLM node is applied. A total/scattered field formulation is applied to excite the space. The source used is an electrically short electric dipole and is described analytically in the time-domain. The method is used to calculate near field distributions (in both the time and frequency domain) and the change in source input impedance of a dipole radiator in the presence of a half-space. Numerical simulations relevant to the detection of buried objects are provided. >

Application of the transmission line matrix method to the analysis of scattering by three-dimensional objects

The transmission line matrix (TLM) method is applied to the analysis of electromagnetic scattering from finite-sized conducting and dielectric objects. The TLM method is a general numerical method for obtaining an approximate solution to the time-dependent form of Maxwell's equations in the presence of geometrically complex environments. The three-dimensional symmetrical-condensed TLM node together with a total/scattered field formulation and a local absorbing boundary condition are applied. Numerical results for a variety of conducting and dielectric objects demonstrate the accuracy of the method. Various guidelines for the successful application of the method to this class of problem are provided.