Ting-Kuang Wang

Electromagnetic bandgap power/ground planes for wideband suppression of ground bounce noise and radiated emission in high-speed circuits

A power/ground planes design for efficiently eliminating the ground bounce noise (GBN) in high-speed digital circuits is proposed by using low-period coplanar electromagnetic bandgap (LPC-EBG) structure. Keeping solid for the ground plane and designing an LPC-EBG pattern on the power plane, the proposed structure omnidirectionally behaves highly efficiently in suppression of GBN (over 50 dB) within the broad-band frequency range (over 4 GHz). In addition, the proposed designs suppress radiated emission (or electromagnetic interference) caused by the GBN within the stopband. These extinctive behaviors of low radiation and broad-band suppression of the GBN is demonstrated numerically and experimentally. Good agreements are seen. The impact of the LPC-EBG power plane on the signal integrity for the signals referring to the power plane is investigated. Two possible solutions, differential signals and an embedded LPC-EBG power plane concept, are suggested and discussed to reduce the impact.

A novel power plane with super-wideband elimination of ground bounce noise on high speed circuits

A novel L-bridged electromagnetic bandgap (EBG) power/ground planes is proposed with super-wideband suppression of the ground bounce noise (GBN) from 600Mz to 4.6GHz. The L-shaped bridge design on the EBG power plane not only broadens the stopband bandwidth, but also can increase the mutual coupling between the adjacent EBG cells by significantly decreasing the gap between the cells. It is found the small gap design can prevent from the severe degradation of the signal quality for the high-speed signal referring to the perforated EBG power plane. The excellent GBN suppression performance with keeping reasonably good signal integrity for the proposed structure is validated both experimentally and numerically. Good agreement is seen.

Overview of Power Integrity Solutions on Package and PCB: Decoupling and EBG Isolation

Mitigating power distribution network (PDN) noise is one of the main efforts for power integrity (PI) design in high-speed or mixed-signal circuits. Possible solutions, which are based on decoupling or isolation concept, for suppressing PDN noise on package or printed circuit board (PCB) levels are reviewed in this paper. Keeping the PDN impedance very low in a wide frequency range, except at dc, by employing a shunt capacitors, which can be in-chip, package, or PCB levels, is the first priority way for PI design. The decoupling techniques including the planes structure, surface-mounted technology decoupling capacitors, and embedded capacitors will be discussed. The isolation approach that keeps part of the PDN at high impedance is another way to reduce the PDN noise propagation. Besides the typical isolation approaches such as the etched slots and filter, the new isolation concept using electromagnetic bandgap structures will also be discussed.

A Novel Power/Ground Layer Using Artificial Substrate EBG for Simultaneously Switching Noise Suppression

A novel power/ground plane for eliminating the power noise in the high-speed digital circuits using an artificial substrate electromagnetic bandgap (AS-EBG) structure is proposed. The AS-EBG is designed by embedding the air rods and high dielectric constant (DK) rods between the coplanar EBG power/ground planes to enhance the stopband bandwidth. A 2-D transmission-line model of the AS-EBG power planes is also developed with experimental verification to explain the mode perturbation and predict the bandgap of the AS-EBG. It is found that over 60% enhancement of bandwidth (from 1.5 to 2.4 GHz) can be achieved for a 3 times 3 AS-EBG power plane compared to the coplanar-EBG power planes by proper design of the high DK rod with DK of 92. Based on SPICE-based modeling, the excellent power/signal integrity performance of the AS-EBG structure is also presented by the chip-package co-simulation in the time domain. It is found over 70% reduction of the simultaneously switching noise can be obtained with good signal eye-diagram improvement.

Design and Modeling of a Stopband-Enhanced EBG Structure Using Ground Surface Perturbation Lattice for Power/Ground Noise Suppression

Based on the ground surface perturbation concept, a novel stopband-enhanced electromagnetic-bandgap (EBG) structure has been proposed to suppress the power/ground noise on a three-layer package. This structure consists of a coplanar periodic pattern on the top layer, a ground plane on the third layer, and a ground surface perturbation lattice on the second layer with eight vias connecting to the ground plane. By designing the dimension and via numbers, the ground surface perturbation lattice can significantly enhance the stopband bandwidth. A generic 1-D circuit model is proposed for the three-layer EBG structure. The reason why the proposed structure can possess wider stopband will be explained. Several test samples are fabricated. The agreement of the stopband between the circuit model and measured results are good.

Modeling Noise Coupling Between Package and PCB Power/Ground Planes With an Efficient 2-D FDTD/Lumped Element Method

An efficient numerical approach based on the 2-D finite-difference time-domain (FDTD) method is proposed to model the power/ground plane noise or simultaneously switching noise (SSN), including the interconnect effect between the package and the print circuit board (PCB). The space between the power and ground planes on the package and PCB are meshed with 2-D cells. The equivalent R-L-C circuits of the via and the solder balls connecting the package and PCB can be incorporated into a 2-D Yee cell based on a novel integral formulation in the time domain. An efficient recursive updating algorithm is proposed to fit the lumped networks into the Yee equations. A test sample of a ball grid array (BGA) package mounted on a PCB was fabricated. The power/ground noise coupling behavior was measured and compared with the simulation. The proposed method significantly reduces the computing time compared with other full-wave numerical approaches.

A novel HU-shaped common-mode filter for GHz differential signals

A novel low-cost filter design for common-mode noise suppression in high-speed differential signals is proposed. It is realized by etching a HU-shaped defected-ground structure (DGS) to perturb the return current of the common-mode noise. A simple LC resonator model for the proposed structure is also developed with good agreement to the full-wave simulation and measurement result. It is found that over 15 dB of common-mode noise suppression can be achieved over a wide frequency ranges from 3.6 to 9.1 GHz, while the differential signals still keep good signal integrity in eye-pattern observation.

A Novel EBG Power Plane with Stopband Enhancement using Artificial Substrate

Based on the conventional low-period coplanar EBG (LPC-EBG) structure, a novel power plane is proposed to extend the bandwidth of the stopband for ground bounce elimination using artificial substrate EBG (AS-EBG) structure. With properly embedded high-K rods and air rods in the substrate of the LPC-EBG power plane, the resonance frequencies can be shifted and thus result in the enhancement of the first stopband. Over 60% improvement of the stopband bandwidth can be achieved in this work. This improvement is also verified by the dispersion diagram calculated using the 2-D transmission-line model.

A new frequency selective surface power plane with broad band rejection for simultaneous switching noise on high-speed printed circuit boards

A novel L-bridged frequency selective surface (FSS) power/ground planes is proposed with super-broadband rejection for simultaneous switch noise (SSN) from 600 Mz to 4.6 GHz. The L-shaped bridge design on the FSS power plane not only broadens the stop-band bandwidth, but also increases the mutual coupling between the adjacent FSS cells with allowing the significant decrease of the gap between the cells. It is found the small gap design can ease the degradation of the signal quality for the signal referring to the perforated FSS power plane. The excellent SSN suppression performance with keeping reasonably good signal integrity for the proposed structure is validated both experimentally and numerically. Good agreement is seen.

A novel stopband-enhanced EBG planes using an Embedded Slow-wave Structure in Low-cost RF-SiP

Based on the slow-wave concept, an EBG power planes with stopband enhancement is proposed by using ground surface perturbation lattice (GSPL) between the coplanar EBG power and ground planes. This structure has 73% and 100% stopband enhancement, respectively, compared to the conventional coplanar and mush-room typed EBG planes. A test sample of 16 unit-cells on a 40 mm square substrate is fabricated with 4 GHz stopband and is validated both by simulation and experiment. It is a low-cost design in SiP because no high-K material is required. Two test chips, C-band LNA (5.6 GHz) and off-chip digital drivers (1.3 GHz), is designed and integrated on the EBG substrate. In the chip-package co-simulation, over 40 dB suppression for the 1.3 GHz harmonics noise on the LNA output is seen for the proposed EBG planes.