Simultaneous Switching Noise Reduction in High Speed Circuits

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.

In this paper, the bandwidth enhancement of planar type electromagnetic bandgap (EBG) structure using dissipative edge termination technique is investigated. Two termination schemes are presented; first with the termination elements along edges of every single EBG patches and second with termination along edges of the whole power plane. In the first case, simulations show that, both lower and upper cutoff frequency is improved for wideband suppression of simultaneous switching noise (SSN). For the second one, lower cutoff frequency is shifted downward from 800MHz of common planar EBG structure to 13MHz. which results in relative bandwidth of 63% higher than the commonly used EBGs. For fast simulation and validation of full-wave simulation, the circuit model of these structures is developed and simulation results are also presented.

Wen-Sheng Zhao from Hangzhou University, China, talks to Electronics Letters about the paper ‘Novel electromagnetic bandgap structure for wideband suppression of simultaneous switching noise’, page 1243 Wen-Sheng Zhao My research fields include interconnect modelling, multiphysics simulations and microwave sensor design. My major research topic is signal and power analysis of silicon via (TSV)-based 3D integrated systems. In recent years, the fourth industry revolution has shown an urgent need to develop next generation memory modules. As a key technology of industry 4.0, TSV-based high-bandwidth memory (HBM) has attracted a lot of interest from both the research and industrial worlds. To guarantee the system performance, it is necessary to perform signal/power/thermal integrity analysis for an HBM module. We are currently working on the issues related to the physical design of HBM modules (such as TSV modeling, equaliser design, and power noise suppression). Modern circuits are developing towards miniaturisation, high frequency and low power consumption, which puts strict constraints on the signal and power integrity design. For example, the operating voltages are continuously lowered, thereby limiting noise margin in power distribution network (PDN). Under such circumstances, power/ground noise is becoming a serious problem. To resolve this issue, various techniques including decoupling capacitor and electromagnetic bandgap (EBG) have been proposed and are under study. In comparison with decoupling capacitor, EBG structure can provide wideband noise suppression, and has been widely explored in the chip, package, and board. To improve the system performance, it is always desirable to increase the stopband bandwidth and rejection level of EBG structure. In this Letter, a power plane with coplanar EBG etched in the S-bridge EBG was proposed. With the proposed EBG structure, an ultrawide bandgap from 0.28 to 25 GHz with a high suppression level of -45 dB was achieved. Moreover, the signal integrity performance of the proposed EBG power plane was examined. The signal integrity can be ensured by utilising differential traces as the transmission structure. The proposed design can be used to reduce power/ground noise efficiently for mixed signal systems. We expect the proposed design to provide performance improvements in various mixed-signal systems in the immediate future. Currently, we are also working on developing EBG structures for silicon interposer and on-chip PDN. In the longer term, we expect that the EBG structures can be further explored and used in the physical design optimisation of HBM systems. As the clock frequency of the circuit system is continuously increased, the frequency of the simultaneous switching noise (SSN) also increases. However, the low-frequency components of the noise are not reduced accordingly. Therefore, the major issue we faced was developing a wide stopband EBG structure with a low cutoff frequency. Moreover, as grooves etched on the power/ground plane have an adverse impact on the signal transmission, we had to pay special attention to ensure signal integrity in the EBG design procedure. When we began studying TSV technologies, there was very little real-world deployment. Although several semiconductor giants such as Samsung presented some TSV based memory modules, these systems remained in the laboratory stage. Nowadays, TSV technology has matured, and the TSV-based HBM modules have been used in many graphics processing units since 2015. We are currently working on the physical design and optimisation (including signal and power integrity analysis) for TSV-based integrated systems. We have seen the introduction of many kinds of techniques (e.g., EBG, equaliser, differential signaling, and active decoupling) which will be helpful for future designs. There is no doubt that further improvements are always desirable to promote wide applications of TSV based integrated systems.

Electromagnetic Bandgap (EBG) structures have been successfully applied for suppressing the Simultaneous Switching Noise (SSN) between the power and ground planes. Aimed at the relative narrow bandwidth and the poor performance in low frequency of the conventional Uniplanar-Compact EBG (UC-EBG) structure, a novel EBG structure formed by adding spiral-shaped metal strips on the conventional UC-EBG is proposed. This new EBG structure significantly enhance the equivalent inductance between the neighboring nuit cells, as well as change the character of the stop-band. Simulation results show that the new EBG structure can achieve a bandwidth reach 4.35GHz.This stop-band is 47.5% wider than the conventional UC-EBG structure, and 17.5% wider than the reference EBG structure in literature. The excellent SSN suppression is achieved between 0.18-4.53GHz in the depth of -40dB.

This paper proposes a novel T-shape electromagnetic bandgap (EBG) structure to suppress simultaneous switching noise (SSN) in mixed-signal systems. Noise is generated due to simultaneous switching multiple drivers in the digital ICs. It is called as SSN. It could propagate between power and ground planes of underlying PCB platform and interfere with the functionality of nearby RF/Analog ICs. So, the RF modules are isolated from the digital module for proper functioning of entire mixed-signal system. A high-impedance surface, called T-shape EBG has been implemented between digital and RF modules. It will exhibit the characteristics of bandgap for a wide frequency range to suppress the propagation of switching noise. A single unit-cell of T-EBG is periodically patterned over one side of the PCB and the other side is kept continuous. In this paper different characteristics of T-EBG have been simulated and verified with the measurement results. A 3 × 3 T-EBG layout provides an isolation of −40 dB from 0.72 to 6.39 GHz. A scaled version of T-EBG is used to shift the bandgap towards higher frequency range from 2.22 to 7.19 GHz. Also, a novel layout methodology has been proposed to broaden the bandgap from 2.02 to 18.84 GHz without reducing the thickness of dielectric substrate.

Simultaneous switching noise (SSN) is one of the major bottlenecks for successful design of high-performance systems. Especially mixed-signal designs are very sensitive to SSN due to the low voltage levels applied in analog circuits. One way of isolation is by placing the digital and analog domains far from each other. Even then, the power planes can transfer noise voltages both vertically and horizontally through out the board and total board area is a major concern in microminiaturized convergent systems. Electromagnetic bandgap structures (EBG) have been successfully applied for such isolation. Although any periodical shape can be used for isolation, only a few shapes have been reported, with various analysis methods. We present a new EBG with narrow slits, which shows a higher attenuation constant compared with existing structures. We also present a new analysis methodology for 2D EBG structures. Finally, a method to scale such EBG structures for different stopband requirements is introduced

Aim of this paper is to describe the simultaneous switching noise (SSN) mitigation by means of a novel electromagnetic band gap (EBG) structure with triangle patches and hexagonal array. The proposed EBG structure allows achieving -40 dB stop band within the frequency range 6.5-9 GHz. Parametric analysis including the radius effect of the metal plated vias, the via length and the distance between the patches is performed by means of full wave simulations, based on the Finite Integration Technique. The impact of the proposed design on the signal integrity is also investigated both in time domain (eye-diagrams and TDR) and frequency domain (S-parameters). Finally dispersion diagrams of the singular unit EBG cell are analyzed by means of eigenmode solver and periodic boundary conditions.

Electromagnetic Bandgap (EBG) structures are increasingly utilized by a variety of microwave and optical devices as filters for unwanted signals. One such application is their incorporation in power distribution network (PDN) of electronic circuits where the EBG structure replaces one of the reference voltage planes thus forming a shielded EBG structure. The EBG induces a wide (on the order of few GHz) omni-directional stopband in the operating frequency range of the PDN which mitigates the so called simultaneous switching noise (SSN) on the power plane. The challenging aspect in designing an EBG for such applications is to achieve a wide stopband centered at low GHz frequencies while maintaining a reasonably small unit cell size and a low profile. Indeed, the dimensions of the unit cell of the EBG structure for low frequency designs can become relatively large with respect to the size of the host dielectric substrate. Therefore, availability of a systematic design approach that can provide a fast and accurate means of performance prediction to enable geometry tweaking and design optimization will be of critical importance in utilizing EBG structures in such applications.

Electromagnetic band gap (EBG) structures can exhibit high impedance surface (HIS) performance on a lossless substrate. However, the performance of an EBG structure is not only determined by the type of element or physical dimensions, but also by the electrical characteristics of the dielectric substrate. The evolution of an EBG structure from HIS to metamaterial absorber with different lossy silicon substrates is analyzed and presented in a reflection magnitude and phase graph. The conductivity of the used substrate is introduced to represent the loss tangent of the silicon substrate. An equivalent circuit model is developed that models the EBG on a lossy silicon substrate. The small differences between calculated and simulated results are explained by ignoring the patch series inductance Ls and the capacitance Ch between the patch and ground plane. Based on the analysis of the reflection characteristics on lossy silicon substrates, this planar EBG structure provides an acceptable performance in BiCMOS technologies, but cannot be used in low-Ohmic CMOS technologies.

To build a stable power distribution network for high-speed digital systems, simultaneous switching noise (SSN) should be sufficiently suppressed in multi-layer PCBs. In this paper, novel uni-planar compact electromagnetic bandgap (UC-EBG) structures with triangular-type unit cells designed on power/ground planes are proposed for the ultra-broadband suppression of SSN. The effect of the structural parameters on the EBG bandgap changing their parameter values is investigated. The SSN suppression performance of the proposed structure is validated both numerically and experimentally. A -30 dB suppression bandwidth for SSN is achieved, starting at 830 MHz and extending to 15 GHz and beyond, thereby covering almost the entire noise band.

The partial element equivalent circuit (PEEC) method and the field equivalence principle are coupled by edge node voltage to quantify the radiation emission of a power/ground plane pair in this paper. Simulation results using the proposed method show a good agreement with the measurement. Meanwhile, in order to suppress the propagation of simultaneous switching noise (SSN) that leads to radiation in packaging, a novel electromagnetic bandgap (EBG) structure is proposed in this paper and it can achieve ultrawideband suppression of SSN.

In this letter, we propose a vertical inductive bridge electromagnetic bandgap (VIB-EBG) structure for size reduction of a unit cell and the wideband suppression of simultaneous switching noise (SSN) in a multi-layer package. With the proposed vertical inductive bridge, the inductance of an EBG unit cell is effectivel increased within a compact unit cell size. Compared to the previous planar bridge EBG structure, the proposed VIB-EBG structure achieves an 86% enhancement of the fractional stopband bandwidth and a 58% reduction in unit cell size. The starting frequency of the first bandgap (fL) is significantly reduced from 4.0 to 1.7 GHz. Wideband SSN suppression with a size reduction was successfully verified by HFSS simulations and measurements.

This paper proposes a reconfigured horn antenna with reduced side-lobe radiation by using electromagnetic band gap (EBG) structure. A mushroom-like structure with a circular-shaped patch as unit cell is designed to achieve a complete EBG. The EBG structure is lined on the metal wall along the E-plane of the horn antenna. This causes the surface waves on the metal wall to be suppressed, resulting in lower side-lobe emission. A conducting wedge is inserted on the gap between the EBG structure and waveguide feed aperture to achieve impedance matching in the antenna. In addition, the proposed horn antenna is suitable for high power systems due to a purely metallic construction of the EBG structure.

The paper aims to determine the Green's functions for different realizations of electromagnetic band-gap (EBG) structures and to calculate the coupling between two dipoles placed above these EBG structures. The applied method avoids the complexity of the Floquet mode approach and the limitations of the surface wave approach. For each considered structure, some sort of asymptotic boundary conditions are derived in which the periodicity of the structure is assumed to be negligible compared to the wavelength. The goal (and the test) of the applied method is to determine properties of each considered EBG structure. Therefore, all important physical phenomena should be taken into account. In order to be able to analyze multilayer structures, the analysis model has been implemented in the G1DMULT algorithm that calculates the spectral domain Green's functions of planar, circular-cylindrical and spherical multilayer structures (Sipus, Z. et al., App. Computational Electromagnetics Soc. J., vol.13, p.243-54, 1998).

In this paper, we present an equivalent circuit (EC) based technique which combined with the numerical method to optimize the EBG structures with simple square-loop frequency selective surfaces (FSSs), they can take on in-phase reflection characteristic in some broad-band electromagnetic band gap (EBG) structures. By using the multilayered FSSs in this type of EBG structure, the surface waves and current could stopped effectively. The geometry and working of the antenna with this EBG structure are detailed and the design method is proposed.