Hideki Asai

Synthesis of time-domain models for interconnects having 3-D structure based on FDTD method

This work describes an efficient method to simulate transient responses of multilayer and multiconductor interconnects having three-dimensional structure. First, the impulse responses between any pair of terminals of lines are obtained by the finite-difference time-domain (FDTD) method, Next, the frequency responses are obtained by the Fourier transform of these transient waveforms. The time-domain models are synthesized from the frequency responses by using the least-square approximation and the complex frequency-hopping technique. Finally, with this model, the transient responses are rapidly simulated by the conventional circuit simulators. In conclusion, the validity of this method is verified by comparison with the time-consuming FDTD simulation.

A synthesis technique of time-domain interconnect models by MIMO type of selective orthogonal least-square method

This paper describes an efficient synthesis technique of time-domain models for interconnects characterized by sampled data. In this method, poles are derived from the sampled data in the frequency domain. Next, the dominant poles and the residues are obtained efficiently by multiinput-multioutput type of selective orthogonal least-square method. Furthermore, time-domain models are derived from the frequency-domain models. Finally, the accuracy and efficiency of the proposed method are substantiated by transient simulation of example circuits using this model.

Optimal placement of decoupling capacitors on PCB using Poynting vectors obtained by FDTD method

This paper describes the searching method for positions of decoupling capacitors on the printed circuit board (PCB). In this method, first, the distributions of electromagnetic field between power and ground planes in the time domain are simulated, using FDTD method. Next, the distribution of Poynting vectors in the frequency domain is investigated, using fast Fourier transform (FFT). Furthermore, this method finds the optimal location of decoupling capacitor so that the Poynting vector is the highest. Finally, we analyze the distribution of magnetic field emission above the signal plane in the x and y axes in the specified range of frequency and verify the validity of our method.

Analysis of power/ground planes by PCB simulator with model order reduction technique

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 interconnects with nonlinear terminations. This simulator is based on the ASSIST environmental tool 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 use of a voltage-controlled current source (VCCS) model. Finally, this simulator is applied to the analysis of power/ground planes of simple PCBs, and the validity is verified.

A synthesis technique of time-domain interconnect models by MIMO type of adaptive least square method

This paper describes an efficient synthesis technique of time-domain models for interconnects characterized by sampled data. In this method, poles are derived from sampled data in the frequency domain. Next, the dominant poles and the residues are obtained efficiently by a MIMO (multi-input multi-output) type of adaptive least squares method. Furthermore, time-domain models are derived from the frequency domain models. Finally, the accuracy and efficiency of the proposed method are substantiated by transient simulation of an example circuit using this model.

An alternating implicit block overlapped FDTD (AIBO-FDTD) method and its estimation with parallel computation

The finite-difference time-domain (FDTD) method has been widely used for solving various types of electromagnetic problems such as anisotropic and nonlinear problems. The FDTD method provides accurate predictions of field behaviors. In this paper, a new algorithm for two-dimensional (2-D) finite-different time-domain (FDTD) is presented in order to increase the maximum time step size and reduce the simulation time by simulating in parallel computation.

Noise analysis of power/ground planes on PCB by SPICE-like simulator with model order reduction technique

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 interconnects with nonlinear terminations. This simulator is based on the environmental tool ASSIST constructed for the development of circuit simulators, and is combined with PRIMA (passive reduced-order interconnect macromodeling algorithm). In this simulator, an efficient implementation of PRIMA is considered using a voltage-controlled current source (VCCS) model. Finally, this simulator is applied to analysis of the power/ground planes of simple PCBs, and the validity is verified.

Efficient synthesis technique of time-domain models for interconnects having 3-D structures based on FDTD method

This paper describes a novel method to simulate transient responses of interconnects having 3-dimensional structure. First, the impulse responses between any pair of terminals of lines are obtained by the finite-difference time-domain (FDTD) method. In this calculation, the characteristic impedance of the interconnect is imposed at every terminal in order to converge quickly the transient waveforms. Next, the frequency responses are obtained by the Fourier transform of these transient waveforms. Then, the time-domain models are synthesized from the frequency responses by using the least square approximation and the complex frequency hopping technique. Finally, with this model, the transient responses are rapidly simulated by the conventional circuit simulators. In conclusion the validity of this method is verified by comparison with the time-consuming FDTD simulation.

High-speed interconnect simulation using MIMO type of adaptive least square method

This paper describes an efficient synthesis technique of time-domain models for interconnects characterized by sampled data. In this method, poles are derived from the sampled data in the frequency domain. Next, the dominant poles and the residues are obtained efficiently by MIMO (multi-input-multi-output) type of adaptive least squares method. Furthermore, time-domain models are derived from the frequency domain models. Finally, the accuracy and efficiency of the proposed method are substantiated by transient simulation of an example circuit using this model.

Expanded GMC for transient analysis of transmission line networks

This paper describes the expanded generalized method of characteristics (GMC) in order to handle large linear interconnect networks. The conventional GMC is applied to model each of transmission lines. Therefore, this method is not suitable for dealing 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 a delay evaluation technique. Finally, it is shown that the present method enables the efficient and accurate simulation of the transmission line networks.