Yen-Hui Lin

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.

A novel power planes with low radiation and broadband suppression of ground bounce noise using photonic bandgap structures

A novel power/ground planes design for eliminating the ground bounce noise (GBN) in high-speed digital circuits is proposed by using low-period photonic bandgap (PBG) structure. Keeping solid for the ground plane and designing low-period PBG pattern on the power plane, the proposed structure omni-directionally behaves highly efficient suppression of GBN (over 50 dB) within broadband frequency range from 1 GHz to 4 GHz. Although the power plane has low-period perforation, the proposed structure still performs with relatively low radiation within the stopband compared with the solid power/ground planes. The low radiation and high suppression of the GBN for the proposed structure are checked both experimentally and numerically. Good consistency is seen.

Numerical and experimental investigation of radiation caused by the switching noise on the partitioned DC reference planes of high speed digital PCB

Influence of the partitioning and bridging of the power/ground planes on the radiation caused by the switching noise on the dc reference planes is investigated both theoretically and experimentally. Based on the three-dimensional finite-difference time-domain modeling, the electromagnetic interference (EMI) performance of the partitioned power/ground planes is studied. Radiated emission at the 3-m distance from the tested boards is measured in a fully anechoic chamber. The measured and the numerical results agree generally well. The radiation behavior of four kinds of partitioned configuration of the power/ground planes is studied. It is found that completely isolating the noise source by the etched slits, or moats, significantly reduces the radiation level at the frequencies near resonance. However, bridges connecting two sides of the moat not only significantly degrade the ability of the EMI protection of the moat, but also excite a new low-frequency resonant mode. The effect of the geometrical parameters, such as the moat size, moat location, bridge width, and bridge position, on the radiation behavior of the printed circuit board is considered. The radiation mechanism of the EMI behavior of the partitioned dc reference planes is discussed.

Investigation of signal quality and radiated emission of microstrip line on imperfect ground plane: FDTD analysis and measurement

Taking four kinds of imperfect ground planes as examples, the effect of the imperfect ground plane on the signal integrity (SI) and electromagnetic interference (EMI) for high-speed digital transmission line on the printed circuit boards (PCB) are investigated both by FDTD simulation and experimental measurement. It is found that good signal quality does not guarantee good EMI performance and ill signal integrity does not imply severe radiated emission. The dominant factor that affects the EMI performance of the signal trace on the reference plane is the path of return current. All simulated S-parameter and EMI behavior of the signal traces are compared with the measurement results. The agreement between them is good.

The effect of test system impedance on measurements of ground bounce in printed circuit boards

Based on the 3D-FDTD approach, an efficient equivalent model employing the embedded resistive voltage source is proposed to simulate the effect of test system impedance on the measurement of the ground bounce noise for the power planes structure in the printed circuit boards (PCB). Compared with the measured results by vector network analyzer, this equivalent model well predicts the impedance behavior of the V/sub cc//GND power planes. The influences of different probe loading conditions of the test system on the measurement of impedance behavior are studied. It is found that the effects of the probing loads on the measurement of the ground bounce noise is significant at the frequencies near the dc point and resonance, but the influences of the probes are small at the frequencies far from resonance. In addition, the transfer characteristics of the power bus in the realistic digital circuits with decoupling capacitance being considered are simulated in the FDTD model. The difference of the transfer behavior between the realistic case without coaxial feed and the measured results with probing effects is also numerically compared. We find that the ground bounce noise in the real circuit can be accurately measured at most frequencies, where the power planes act in very low impedance, except at the frequencies near dc and resonance frequencies, where the power planes behave in relatively higher impedance characteristics.

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.

Analysis of radiation caused by SSN and transmission line by combining the equivalent circuits of active IC into FDTD

Simultaneous switching noise (SSN) caused by transient currents degrades the signal integrity (SI) and electromagnetic interference (EMI) performance of high-speed digital circuits (HSDC). In order to analyze these effects, an accurate full-wave modeling approach, which includes active devices and passive interconnects (including power and ground planes), is required. We link the equivalent circuit of an active IC into an FDTD algorithm by the equivalent current-source method (ECSM). The radiation behavior of the switched IC on PCB circuits can thus be investigated. It is found that two mechanisms dominate for the radiations of the switched IC. One is the GBN (ground bounce noise) radiation and the other is the signal trace radiation. The interaction between them and an elimination method is discussed.

Crosstalk characterization of high-speed interconnects in time-domain

As the edge rate becomes faster in digital signals, signal integrity (SI) analysis, such as reflection, delay, and crosstalk becomes increasingly important. This paper proposes an efficient modeling approach, which combines the finite-difference time-domain (FDTD) method and multi-conductor layer peeling technique for differential transmission lines, to extract the equivalent model and the characteristic impedance of the differential transmission lines. These extracted models can be employed to predict the crosstalk of the high-speed signals.

NSTL evaluation of the compact EMC chamber with ferrite tiles being partially lined on the floor ground

Compact fully anechoic chambers may gradually replace open area test sites as the preferred type of testing facility for the measurement of radiated emissions. Based on FDTD modeling approach, a numerical tool with the measuring tunable dipole antennas being considered is established to simulate the NSTL performance of the compact EMC chamber with different layout design of ferrite tiles. This paper theoretically and experimentally investigates the suitability of a compact fully anechoic chamber with ferrite tiles being partially lined on the floor ground as a free-space environment at frequency range below 300MHz. Furthermore, several designs of reduced coverage of the ferrite tiles in the compact chamber are proposed and discussed.