An efficient approach for power delivery network design with closed-form expressions for parasitic interconnect inductances

Investigation of a dc power delivery network, consisting of a multilayer PCB using area fills for power and return, involves the distributed behavior of the power/ground planes and the parasitics associated with the lumped components mounted on it. Full-wave methods are often employed to study the power integrity problem. While full-wave methods can be accurate, they are time and memory consuming. The cavity model of a rectangular structure has previously been employed to efficiently analyze the simultaneous switching noise (SSN) in the power distribution network. However, a large number of modes in the cavity model are needed to accurately simulate the impedance associated with the vias, leading to computational inefficiency. A fast approach is detailed herein to accelerate calculation of the summation associated with the higher-order modes. Closed-form expressions for the parasitics associated with the interconnects of the decoupling capacitors are also introduced. Combining the fast calculation of the cavity models of regularly shaped planar circuits, a segmentation method, and closed-form expressions for the parasitics, an efficient approach is proposed herein to analyze an arbitrary shaped power distribution network. While it may take many hours for a full-wave method to do a single simulation, the proposed method can generally perform the simulation with good accuracy in several minutes. Another advantage of the proposed method is that a SPICE equivalent circuit of the power distribution network can be derived. This allows both frequency and transient responses to be done with SPICE simulation.     

Partial uniplanar compact electromagnetic bandgap combined with high-impedance surface to suppress simultaneous switching noise

Proposed is a design for a partial uniplanar compact electromagnetic bandgap (UC-EBG) structure, in conjunction with a high-impedance surface (HIS), to suppress simultaneous switching noise (SSN) over the wide frequency range 0.38-15.494-GHz. Different from the conventional methods, which use an EBG plane, the proposed structure uses only two UC-EBGs at the excitation and receiving ports to suppress SSN. This technique can be applied to sensitive circuits to maintain their power integrity. The other region maintains good signal integrity when a signal return path is referenced to an EBG plane.     

A simple finite-difference frequency-domain (FDFD) algorithm for analysis of switching noise in printed circuit boards and packages

Simultaneous switching noise (SSN) compromises the integrity of the power distribution structure on multilayer printed circuit boards (PCB). Several methods have been used to investigate SSN. These methods ranged from simple lumped circuit models to full-wave (dynamic) three-dimensional Maxwell equations simulators. In this work, we present an efficient and simple finite-difference frequency-domain (FDFD) based algorithm that can simulate, with high accuracy, the capacity of a PCB board to introduce SSN. The FDFD code developed here also allows for simulation of real-world decoupling capacitors that are typically used to mitigate SSN effects at sub 1 GHz frequencies. Furthermore, the algorithm is capable of including lumped circuit elements having user-specified complex impedance. Numerical results are presented for several test boards and packages, with and without decoupling capacitors. Validation of the FDFD code is demonstrated through comparison with other algorithms and laboratory measurements.     

Full-wave simulation of electromagnetic coupling effects in RF and mixed-signal ICs using a time-domain finite-element method

This paper describes the computer simulation and modeling of distributed electromagnetic coupling effects in analog and mixed-signal integrated circuits. Distributed electromagnetic coupling effects include magnetic coupling of adjacent interconnects and/or planar spiral inductors, substrate coupling due to stray electric currents in a conductive substrate, and full-wave electromagnetic radiation. These coupling mechanisms are inclusively simulated by solving the full-wave Maxwell's equations using a three-dimensional (3-D) time-domain finite-element method. This simulation approach is quite general and can be used for circuit layouts that include isolation wells, guard rings, and 3-D metallic structures. A state-variable behavioral modeling procedure is used to construct simple linear models that mimic the distributed electromagnetic effects. These state-variable models can easily be incorporated into a VHDL-AMS simulation providing a means to include distributed electromagnetic effects into a circuit simulation.     

Bandwidth Enhancement for SSN Suppression Using a Spiral‐Shaped Power Island and a Modified EBG Structure for a λ/4 Open Stub

This paper proposes a spiral‐shaped power island structure that can effectively suppress simultaneous switching noise (SSN) when the power plane drives high‐speed integrated circuits in a small area. In addition, a new technique is presented which greatly improves the resonance peaks in a stopband by utilizing λ/4 open stubs on a conventional periodic electromagnetic bandgap (EBG) power plane. Both proposed structures are simulated numerically and experimentally verified using commercially available 3D electromagnetic field simulation software. The results demonstrate that they achieve better SSN suppression performance than conventional periodic EBG structures.     

Double-Stacked EBG Structure for Wideband Suppression of Simultaneous Switching Noise in LTCC-Based SiP Applications

We propose a novel electromagnetic bandgap (EBG) structure with a significantly extended noise isolation bandwidth, called a double-stacked EBG (DS-EBG) structure, fabricated on a low-temperature co-fired ceramic (LTCC) multilayer substrate. The DS-EBG structure was devised for wideband suppression of simultaneous switching noise (SSN) coupling in system-in-package (SiP) applications. Our design approach was enabled by combining two EBG layers embedded between the power and ground planes. The two EBG layers had different bandgaps from using different cell sizes. Enhanced wideband suppression of the SSN coupling was validated using a 11.4-GHz noise stop bandwidth with 30-dB isolation in time and frequency domain measurements up to 20GHz.     

A Novel Time-Domain Approach for Extracting Broadband Models of Power Delivery NetworksWith Resonance Effect

Resonance noise, or power/ground bounce noise, on the power and ground planes of high-speed circuit packages is one of the main concerns of signal integrity or power integrity issues. A novel time-domain approach is proposed to synthesize the broadband models of the power/ground planes with resonance effect. Using waveforms either from measurements by time-domain reflectrometry or simulations by the finite-difference time-domain method, the time-domain step response of the planes is characterized with a pole-residue representation obtained through the matrix pencil method. Lumped circuit equivalent circuit models are then synthesized through the pole-residue representations. The synthesized model can accurately predict the resonance behavior of power/ground planes over a wide frequency range. These models can be efficiently incorporated into the currently available circuit simulator such as HSPICE for the consideration of power/ground bouncing noise in high-speed circuits. Three cases are tested to demonstrate the validity and broadband accuracy of the proposed approach.      

A compact multilayer IC package model for efficient simulation, analysis, and design of high-performance VLSI circuits

A multilayered integrated circuit (IC) package structure is composed of many signal layers, power layers, and ground layers. Particularly, the whole planes are assigned for the power and ground of the system. Accordingly, the generic circuit representation of such a complicated multilayer IC package becomes too complicated to efficiently evaluate its electrical performance. In this work, a novel compact package circuit model for the efficient simulation and analysis of such complicated IC packages is presented. Unlike the conventional models, current distributions within the package are modeled by introducing a compact partial plane circuit model. Thus, the proposed package model is much simpler than the conventional generic circuit models, while its accuracy is preserved. Thereby, today's complicated IC packages can be efficiently evaluated and analyzed. Its accuracy and efficiency are verified by benchmarking it with a conventional generic package circuit model; this conventional model may not be practical to use for package evaluation and analysis. It is then shown that the proposed model can be efficiently applied for the signal integrity verification of complicated IC packages and high-performance VLSI circuits.     

Scalable Compact Circuit Model for Differential Spiral Transformers in CMOS RFICs

A new compact circuit model for differential spiral transformers in CMOS radio frequency integrated circuits (RFICs) is developed in this paper. The model consists of two coupled “$hbox2-pi$” subcircuits for each inductor coil in the transformer. All the values of the circuit elements can be analytically calculated according to the process parameters and the device's geometric dimensions, making the model highly scalable and predictive. The model has very good accuracy as validated by comparison to a 2.5-dimensional full-wave numerical electromagnetic field solver.     

Analysis of power delivery network constructed by irregular-shaped power/ground plane including densely populated via-hole

The high speed and low power trend has imposed more and more importance on the design of the power distribution network (PDN) using multilayer printed circuit boards (PCBs) for modern microelectronic packages. This paper presents a fast and efficient analysis methodology in frequency domain for the design of a PDN with a power/ground plane pair, which considers the effect of irregular shape of the power/ground plane and densely populated via-holes. The presented method uses parallel-plate transmission line theory with equivalent circuit model of unit-cell grid considering three-dimensional geometric boundary conditions. Characteristics of PDNs implemented by perforated planes including a densely populated via-hole structure is quantitatively determined based on full-wave analysis using the finite-difference time-domain (FDTD) periodic structure modeling method and full-wave electromagnetic field solver. Using a circuit simulator such as popularly used SPICE and equivalent circuit models for via-hole structure and perforations, the authors have analyzed input-impedance of the power/ground plane pair. Since the presented method gives an accurate and fast solution, it is very useful for an early design of multilayer PCBs.     

A Double-Surface Electromagnetic Bandgap Structure With One Surface Embedded in Power Plane for Ultra-Wideband SSN Suppression

In this letter, a double-surface electromagnetic bandgap (EBG) structure with one EBG surface embedded in power plane is proposed for ultra-wideband simultaneous switching noise (SSN) suppression in printed circuit boards. The SSN suppression bandwidth is broadened to wider than 30 GHz with a low start frequency by combining traditional EBG structure and the coplanar EBG structure which is embedded in the power plane. Because the coplanar EBG surface is embedded in the power plane, no additional metal layer is introduced by the double-surface EBG structure. Simulations and measurements are performed to verify the broadband SSN suppression, high performance is observed.     

A Compact Broadband PHEMT MMIC Power Amplifier for K through Ka-band Applications

A compact and broadband MMIC power amplifier operating from 18 GHz to 35 GHz is developed for K- through Ka-band applications implementing a rigorous electromagnetic (EM) simulation of closely spaced matching networks. The EM simulation results in a compact chip size as small as 2.16 mm × 2.0 mm and isolations of less than -25 dB up to 40 GHz between neighboring distributed structures. The two-stage balanced power amplifier fabricated using a 0.25 µm AlGaAs/InGaAs/GaAs PHEMT technology has an average gain of 11 dB, return losses less than -10 dB, and P1 dB above 20.5 dBm from 18 GHz to 35 GHz. This compact and broadband MMIC power amplifier is suited for power amplifiers for most K through Ka-band communication systems such as the FSS, LMDS, and ITS.     

基于低温共烧陶瓷技术的Ku波段低噪声放大器

设计了一种基于低温共烧陶瓷(Low temperature co-fired ceramic)技术的Ku波段低噪声放大器。将低噪声放大器的MMIC芯片集成于LTCC基板中,利用三维全波电磁场软件设计和优化了LNA的无源模型,包括金丝、通孔阵列和多层地平面。金丝用来连接MMIC芯片和微带,通孔用来连接不同地平面。分析了两根平行金丝的π型等效模型并提取了该模型的参数,研究了通孔阵列的间距以得到良好的接地效果。为了得到LNA完整的仿真,将整个无源模型的电磁场数据导出到ADS软件中,并和MMIC芯片的S参数一起协同仿真,最终得到优化结果。测试结果表明该LNA在12~17GHz的频段内,具有40dB的增益,±1.215dB的带内平坦度,2.9dB的噪声系数。     

A novel ultra-compact resonator for Superconducting thin-film filters

This paper proposes a novel thin-film resonator structure, which combines the microstrip resonator and the coplanar resonator to form an integrated resonator. This resonator structure has an extremely compact size, as compared to the thin-film resonator structures from the literature, and its resonant frequency was shown theoretically to be less sensitive to, or even insensitive to, the thickness of the substrate. An eight-pole quasi-elliptic filter based on this novel resonator was designed. The exact filter layout was simulated and optimized by full-wave electromagnetic simulation using IE3D software. The full-wave simulated filter response was in good agreement with the theoretical filter response. A filter was fabricated on a double-sided YBa/sub 2/Cu/sub 3/O/sub 7/ thin film epitaxially grown on a 2-in-diameter MgO wafer. The measured filter response showed a bandwidth of 1.5 MHz and a center frequency of 850.3 MHz at 78 K. The insertion loss at the passband center was 1 dB, corresponding to a filter Q of 28 000. Steep rejection slopes were obtained at the band edges and rejections reached over 70 dB in approximately 300 kHz from the passband edges. No pronounced changes were observed for input power levels between -20-0 dBm, indicating a relatively high power-handling capability of the filter.     

Compact model generation for on-chip transmission lines

An approach for the fast and accurate generation of compact distributed circuit models for on-chip transmission lines on lossy silicon substrates is presented. Using a novel ABCD matrix partitioning procedure, accurate distributed circuit models are extracted from scattering parameters obtained from measurements and calibrated full-wave electromagnetic simulations for a small set of transmission-line geometries spanning ranges of design parameter values. A feedforward artificial neural network is trained using the extracted results, and applied to generate accurate compact models for arbitrary values within the bounds of the training ranges. Consequently, the model generation time is greatly reduced compared to conventional approaches by exploiting the interpolation capabilities of the neural network. The compact model generator is fully compatible with HSPICE and SPECTRE-RF and is easily incorporated into parasitic-aware RF circuit design and optimization tools.     

介质型EBG结构对同步开关噪声抑制的有限元分析

研究了介质型电磁带隙结构对高速电路中电源/ 地平面间同步开关噪声的抑制作用。该介质型电磁带隙结构在抑制同步开关噪声的同时未破坏高速信号的电流返回路径,使高速信号的信号完整性得以保持。利用电磁场有限元方法将电源/地平面间同步开关噪声抑制的三维问题转化成二维问题进行处理,提高了计算效率。分析了介质型电磁带隙结构的介电常数对噪声抑制带宽的影响,利用了三维全波电磁场仿真软件HFSS对二维数值结 果进行仿真验证,仿真结果与数值计算结果基本吻合,验证了二维数值算法的正确性。     

Fast analysis of bounces on power/ground planes using even-odd partition

A novel method for analyzing the bounces on structure of parallel power/ground planes by using the even-odd mode partition is presented in this paper. Based on the distributed RLCG circuit model derived from the two dimensional electromagnetic field equations of the power/ground planar structure, this method can speed up the circuit simulation of the bounces on power/ground planes by using even-odd mode partition. Furthermore, the method can be used to evaluate the effects of the terminated decoupling capacitors and the hole structures on power/ground plane. The numerical examples demonstrate that the method has both high efficiency and good precision.     

Stable and Effective Full-Wave PEEC Models by Full-Spectrum Convolution Macromodeling

A novel technique for time domain partial element equivalent circuits (PEECs) modeling is presented. The PEEC method is a well-known numerical method for creating full-wave models of interconnection structures in the frequency and time domains, which are being used for modeling electromagnetic compatibility (EMC) problems. The time domain solutions by PEEC can show the so-called late-time instabilities. Several attempts to overcome this problem have been made in the literature. The cause for instability has been revealed, and a stable time domain model has been given, however, with a reduced computational efficiency. A stable full-wave PEEC model based on a convolution macromodeling with a faster computation time is developed and tested in this paper     

Physics-Based Via and Trace Models for Efficient Link Simulation on Multilayer Structures Up to 40 GHz

Analytical models for vias and traces are presented for simulation of multilayer interconnects at the package and printed circuit board levels. Vias are modeled using an analytical formulation for the parallel-plate impedance and capacitive elements, whereas the trace-via transitions are described by modal decomposition. It is shown that the models can be applied to efficiently simulate a wide range of structures. Different scenarios are analyzed including thru-hole and buried vias, power vias, and coupled traces routed into different layers. By virtue of the modal decomposition, the proposed method is general enough to handle structures with mixed reference planes. For the first time, these models have been validated against full-wave methods and measurements up to 40 GHz. An improvement on the computation speed of at least two orders of magnitude has been observed with respect to full-wave simulations.