This paper describes the expanded generalized method of characteristics (GMC) in order to handle large linear interconnect networks. The conventional GMC is applied to modeling each of transmission lines. Therefore, this method is not suitable to deal with large linear networks containing many transmission lines. Here, we propose the expanded GMC method to overcome this problem. This method computes a characteristic impedance and a new propagation function of the large linear networks containing many transmission lines. Furthermore the wave propagation delay is removed from the new wave propagation function using delay evaluation technique. Finally, it is shown that the present method enables the efficient and accurate simulation of the transmission line networks.

This paper presents the selective orthogonal matrix least-squares (SOM-LS) method for representing a multiport network characterized by sampled data with the rational matrix, improving the previous works, and providing new criteria. Recently, it is needed in a circuit design to evaluate physical effects of interconnects and package, and the evaluation is done by numerical electromagnetic analysis or measurement by network analyzer. Here, the SOM-LS method with the criteria will play an important role for generating the macromodels of interconnects and package in circuit simulation level. The accuracy of the macromodels is predictable and controllable, that is, the SOM-LS method fits the rational matrix to the sampled data, selecting the dominant poles of the rational matrix. In examples, simple PCB models are analyzed, where the rational matrices are described by Verilog-A, and some simulations are carried out on a commercial circuit simulator.

This paper describes an efficient method to simulate lossy coupled transmission lines based on the delay evaluation technique. First, we review the previous methods, and refer to several problems concerned with these methods. Next, a novel waveform relaxation-based simulation method is proposed, which uses the delay evaluation technique. This method enables to obtain the accurate transient waveforms using smaller number of moments than the other moment methods use, and is modified for acceleration by the generalized line delay window partitioning (GLDW) technique. Finally, this method is implemented in the waveform relaxation-based circuit simulator DESIRE3T+, and the performance is estimated.

This paper presents generating stable and sparse reluctance/inductance matrix from the inductance matrix which is extracted under insufficient discretization. To generate the sparse reluctance matrix with guaranteed stability, the original matrix has to be (strictly) diagonally dominant M matrix. Hence, the repeated inductance extractions with a smaller grid size are necessary in order to obtain the well-defined matrix. Alternatively, this paper provides some ideas for generating the sparse reluctance matrix, even if the extracted reluctance matrix is not diagonally dominant M matrix. These ease the extraction tasks greatly. Furthermore, the sparse inductance matrix is also generated by using double inverse methods. Since reluctance components are not still supported in SPICE-like simulators, generating the sparse inductance matrix is more useful than the sparse reluctance one.

This report describes a new methodology for the optimal placement of decoupling capacitors on the printed circuit board (PCB). This method searches the optimal position of decoupling capacitor so that the impedance characteristics at the power supply is minimized in the specified frequency range. In this method, the PCB is modeled by the PEEC method to handle the 3-dimensional structures and Krylov-subspace technique is applied to obtain efficiently the impedance characteristics in the frequency domain.

This report describes an acceleration technique to synthesize time-domain macromodels of interconnects using FDTD method. In FDTD calculation, the characteristic impedance of the interconnect is inserted into every terminal in order to damp quickly the transient waveforms. Additionally, an efficient technique for analyzing the macromodels is proposed. We demonstrate the efficiency of this method with examples.

With the progress of integration of circuits and PCBs (Printed Circuit Boards), novel techniques have been required for verification of signal integrity. Noise analysis of the power/ground planes is one of the most important issues. This paper describes a high-speed simulator for PCBs which contain the interconnects with nonlinear terminations. This simulator is based on the environmental tool ASSIST (Assistant System for Simulation Study) constructed for development of the circuit simulators, and is combined with PRIMA (Passive Reduced-Order Interconnect Macromodeling Algorithm). In this simulator, an efficient implementation of PRIMA is considered with using a voltage-controlled current source (VCCS) model. Finally, this simulator is applied to the analysis of power/ground planes of the simple PCBs, and the validity is verified.

This paper describes a waveform relaxationbased coupled lossy transmission line circuit simulator DESIRE3T+. First, the generalized method of characteristics (GMC) is reviewed, which replaces a lossy transmission line with an equivalent disjoint network. Next, the generalized line delay window (GLDW) partitioning technique is proposed, which accelerates the transient analysis of the circuits including transmission lines replaced by GMC model. Finally GMC model and GLDW technique are implemented in hte relaxation-based circuit simulator DESIRE3T+ which can analyze bipolar transistor circuits by using the dynamic decomposition technique, and the performance is estimated.

Integration of spot-size converters (SSCs) with semiconductor optical amplifiers (SOAs) that improves chip-fiber optical coupling is inevitable for realizing high performance SOA modules. In this paper SSCs that can be easily integrated with SOAs and have little influence on the polarization sensitivity have been studied. We found that polarization insensitive active width-tapered SSCs can be realized by an optimum waveguide design of tensile-strained bulk structures. The SOA module exhibited large fiber-to-fiber gain (> 19 dB), small polarization sensitivity (< 0.4 dB), high fiber-coupled saturation output power (> +11.7 dBm) and record low module noise figure (< 6.3 dB) for the signal wavelength range of 1530-1560 nm.

This paper describes an efficient method for the macromodel generation of hybrid systems which are composed of electromagnetic systems and lumped RLC circuits. In our method, electromagnetic systems are formulated as finite-difference frequency-domain (FDFD) equations, and RLC circuits are formulated as nodal equations. Therefore, unlike the partial-element equivalent-circuit (PEEC) method, the technique presented here does not need any 3-dimensional capacitance and inductance parameter extractions to model interconnects, LSI packages and printed circuit boards. Also the lumped RLC elements can be easily included in the hybrid system of equations, thus it is convenient to model some passive components, such as bypass capacitors. The model order reduction technique is utilized in order to construct macromodels from hybrid system of equations. The accuracy of the proposed method is substantiated with some numerical examples.

This paper presents a fast transient simulation method for power distribution networks (PDNs) of the PCB/Package. Because these PDNs are modeled as large-scale linear circuits consisting of a large number of RLC elements, it takes large costs to solve by conventional circuit simulators, such as SPICE. Our simulation method is based on the leapfrog algorithm, and can solve RLC circuits of PDNs faster than SPICE. Actual PDNs have frequency-dependent dispersions such as the skin-effect of conductors and the dielectric loss. To model these dispersions, more number of RLC elements are required, and circuit structures of these dispersion models are hard to solve by using the leapfrog algorithm. This paper shows that the circuit structures of dispersion models can be converted to suitable structures for the leapfrog algorithm. Further, in order to reduce the simulation time, our proposed method exploits parallel computation techniques. Numerical results show that our proposed method using single processing element (PE) enables a speedup of 20-100 times and 10 times compared to HSPICE and INDUCTWISE with the same level of accuracy, respectively. In a large-scale example with frequency-dependent dispersions, our method achieves over 94% parallel efficiency with 5PEs.

In this paper, we show the generalized method of the time-domain circuit simulation based on LIM. Our method is applicable to any structure of circuits by combination with the SPICE-like method. In order to show the validity and efficiency of our method, an example circuit is simulated and the proposed method is compared with the conventional ones.

In this paper, we propose a new method which makes transient simulation faster for the circuit including both nonlinear and linear elements. First, the method for generating the projection matrix with Krylov-subspace technique is described. The order of the circuit equation is reduced by congruence transformation with the projection matrix. Next, we suggest a method which can calculate the reduced Jacobian matrix directly in each Newton-Raphson iteration. Since this technique does not need to calculate the original size of Jacobian matrix, the calculation cost is reduced drastically. Therefore, efficient circuit simulation can be achieved. Finally, our method is applied to some example circuits and the validity of the nonlinear circuit reduction technique is verified.

This paper presents a framework for modeling and mixed-mode simulation of circuits/interconnects and electromagnetic (EM-) radiations. The proposed framework investigates the signal integrity in VLSI chips, packages and wiring boards at the GHz-band level, and verifies the electromagnetic interference (EMI) and the electromagnetic compatibility (EMC) of high-speed systems. In our framework, the frequency characteristics of interconnects and EM-radiations are extracted by the full-wave FDTD simulation. The macromodels of interconnects are synthesized as SPICE subcircuits, and the impulse responses of EM-radiations are stored in the database. Once the macromodels are synthesized, the circuit simulation with the consideration of EM-effects can be performed by using SPICE. The EM-field distributions can be also easily calculated by taking convolutions of pre-simulated EM impulse responses and the SPICE results.