The ground surface perturbation lattice (GSPL) structure is investigated to suppress power noise in the power distribution network of mixed signal circuits. In order to enhance the bandwidth of the noise suppression, the GSPL structure is implemented by using multiple vias in the mushroom-like electromagnetic bandgap structure. Under the concept of multiple vias, the lower and upper bound cutoff frequencies of the bandgap are influenced by the position of the vias. An optimum position for the vias is found to achieve maximum stopband bandwidth. In this paper, the stopband mechanism of GSPL structure is investigated and the corresponding equivalent circuit model is proposed to quickly predict the lower and upper bound cutoff frequencies. Suitable test boards are fabricated and measured to demonstrate the accuracy of the design concept. The result shows that there is a good consistency between simulated, modeled, and measured results.

Bandwidth Enhancement Based on Optimized Via Location for Multiple Vias EBG Power/Ground Planes

The present contribution performs a systematic analysis of the impact of planar (or 2-D) EBG structures on the signal transmission performances of single ended and differential striplines that have the patterned plane of the EBG structure as a current reference.

Signal Integrity Analysis of Single-Ended and Differential Striplines in Presence of EBG Planar Structures

This paper approaches the filtering behavior of Electromagnetic Bandgap (EBG) structures. The transfer function, in terms of S-parameters, of a single ended and a differential microstrip line referenced to an EBG plane are considered: the notches (causing signal attenuation) and flat regions (causing signal propagation) are related to the geometry and characteristics of the EBG structure and can be designed to filter out unwanted harmonic components of the signal. A different EBG-like structure is proposed and its performances analyzed.

Common mode filtering performances of planar EBG structures

In this paper, a power plane with localized planar electromagnetic bandgap (EBG) structure is designed for suppressing simultaneous switching noise (SSN) in mixed-signal systems. Nonbianisotropic complementary split ring resonator with a bandgap behavior is used to constitute the EBG cells, which are partially located on the power plane to prohibit the noise propagation within the board. An equivalent circuit model is proposed to predict the lower cutoff frequency of the transmission behavior. From the measured results, an ultrawideband mitigation of SSN from 0.26 to 25 GHz is achieved with a high suppression level of -50 dB. Furthermore, signal integrity problem is investigated, and it is found that partial discontinuities of the proposed design can reduce the influence on signal quality compared with the traditional global EBG structure. In addition, the proposed design can lower the electromagnetic interference radiation from edges of the board.

Localized Planar EBG Structure of CSRR for Ultrawideband SSN Mitigation and Signal Integrity Improvement in Mixed-Signal Systems

An efficient analysis using the contour integral method (CIM) for the modeling of inhomogeneous substrates with circular or arbitrarily shaped dielectric inclusions in planar structures is presented. It is shown how the segmentation method is applied to obtain circuit parameters as well as field values and how different boundary conditions can be implemented. Such an analysis is especially useful for the modeling of photonic crystals power/ground layers (PCPLs) in power delivery networks (PDNs) on printed circuit boards (PCBs). For circular inclusions, an analytical solution is presented, which improves efficiency and accuracy of the proposed method. An equivalent circuit model for cylindrical inclusions is derived, in order to obtain an effective capacitance for low frequencies and an estimate for parasitic effect at higher frequencies. It is shown how circular inclusions can be compared to decoupling capacitors on a basis of impedances. The method is validated with full-wave simulations showing a reduction in simulation time of about one order of magnitude.

An Efficient Analysis of Power/Ground Planes With Inhomogeneous Substrates Using the Contour Integral Method

A photonic crystal fence is proposed for simultaneous switching noise mitigation in power/ground plane pairs with minimum use of the high dielectric constant for the rods. In particular a 45 degree rotated square lattice consisting in three rows of periodic rows is used for the fence. Broadband and high efficient noise suppression can be still achieved while minimizing the cost of the structure. A sensitivity analysis investigating the impact of 1) the normalized rods radius, 2) the number of rods rows, and 3) the value of the dielectric rods is performed and design parameters for the calculation of the stop bands are extracted. The normalized radius is not sufficient to correctly predict the stop band of the fence; instead multiple design parameters are necessary. It is found that an extra row of high dielectric constant material introduces an attenuation for the noise coefficient of around 8-10 dB per row and multiple stop bands are predicted while increasing the relative dielectric constant of the rods from 50 to 300. A one-dimensional circuit model is finally developed for a quick and efficient prediction of the stop band performances of these structures.

Noise Coupling Mitigation in PWR/GND Plane Pair by Means of Photonic Crystal Fence: Sensitivity Analysis and Design Parameters Extraction

Object of this paper is the signal integrity analysis of printed circuit boards with electromagnetic bandgap structures. In particular the signal quality of single-ended and DIFF lines is discussed both in time and frequency domain (S-parameters, TDR and eye-diagrams). Two different configurations (two dimensional and three dimensional) of electromagnetic bandgap structures are analyzed by means of a three dimensional full wave field simulator based on the finite integration technique. Results show a consistent improvement of the signal integrity when DIFF signaling is used, while keeping the typical advantage of noise mitigation due to electromagnetic bandgap layers.

Signal integrity analysis of single-ended and differential signaling in PCBs with EBG structure

The present paper discusses the need of using full wave analysis for signal integrity studies on high speed differential backplane pairs with signals ranging from 2.5 to 6.25Gbs. The traces and the associated vias are imported from a commercial layout tool and then simulated by means of a 3D full wave simulator. The impact of the back drilling technique to control the via stub effect and the impact of the ground vias surrounding the signal pair is studied in terms of both S- parameter and eye-diagram waveforms. An equivalent circuit model is then extracted by using the Model Order Reduction (MOR) technique built in the same simulation tool.

Broadband signal integrity characterization of a high speed differential backplane pair

This paper investigates the impact of return path discontinuities on both signal and power integrity of high speed interconnects. A test board is built for the purpose and 4 different configurations are analyzed and correlation between measurements and simulations (coming from a full wave 3D EM field simulator) results is also presented. Both time and frequency domain results are analyzed and design guidelines are provided. It is observed that return path discontinuities have a sensible impact on ground bounce in single-ended signals; however the differential signaling can drastically reduces it. Discontinuities from gaps in return paths (e.g. plane splits) and connectors impact the differential signals on both insertion loss and cross talk. The real value of return/grounding vias is to reduce the common signal noise.

Analysis of return path discontinuities in multilayer PCBs and their impact on the signal and power integrity

This paper investigates the suppression of unwanted noise in high speed power buses by the adoption of Photonic Crystal Power/Ground Layer (PCPL) structure. The performance of PCPL with different densities of high dielectric rods is analyzed in terms of S-parameters and Electric field distribution. An attempt is made in order to relate geometrical properties (like rods' density and filling ratio) to the shift of the central frequency of the band gaps a well as bandwidth. The simulated results are validated by means of comparison with measured data.

A. Ciccomancini Scogna

Papers

Noise Coupling Mitigation in PWR/GND Plane Pair by Means of Photonic Crystal Fence: Sensitivity Analysis and Design Parameters Extraction

Signal integrity analysis of single-ended and differential signaling in PCBs with EBG structure

Broadband signal integrity characterization of a high speed differential backplane pair

Analysis of return path discontinuities in multilayer PCBs and their impact on the signal and power integrity

Impact of Photonic Crystal Power/Ground Layer density on power integrity performance of high-speed power buses