GBN(GROUND BOUNCE NOISE) TO MITIGATION USING UNIPLANAR COMPACT EBG STRUCTURE WITH MEANDERED BRIDGE FOR UWB APPLICATIONS * B Dinesh raja, k Vasudevan Department Electronics and Communication Engineering,Thiagarajar College of Engineering Madurai – 625 015 1dineshrajameece@gmail.com 2kvasudevan@tce.edu Abstract— The main goal of this paper is to suppressed Ground bounce noise in ultra wide band(UWB). A modified uniplanar compact EBG(Electro magnetic band-gap) structure which integrates meandered bridged EBG structure with slits is proposed for UWB(Ultra wide band).Bandwidth to cover from 450 MHz to 10 GHz at -40 db isolations and also lower edge ot the bandgap is shifted towards the lower freqency.Existing uniplanar compact EBG is modified to improve isolation level, bridges are replaced with meander lines, are followed to improve isolation over band gap is simulated . Simulation work done in CST Microwave studio and analyze in frequency domain solver And Plot the results of s21 parameter Keywords— EBG( Electro magnetic bandgap),bandwidth,GBN (Ground bounce noise),Ultra wide band(UWB) I. INTRODUCTION In recent years current packaging technologies, data, video, voice sensing and other function modules such as digital, analog, RF, memory devices, sensors, etc. are required to be integrated into one package known as “system on package “or “system in package,” which are used more widely in cell phones and other communication systems . The forthcoming generation of processors will have several parts of chipsets integrated in the same package thus resulting in complex integrated circuits.GROUND bounce noise[1] (GBN) on the power/ground planes is becoming one of the major concerns for the high-speed digital computer systems due to fast edge rates, using high clock frequencies, and low voltage levels. Because of the parallel-plate waveguide structure between power and ground planes in the high-speed packages, the resonance modes of the parallel-plate waveguide can be excited by the GBN. The resonance noise propagating between the power and ground planes not only causes signal integrity (SI) problems for the circuits , but also results in significant radiation or electromagnetic interference (EMI) issues.[2] Simultaneous switching noise (SSN)[3], also known as ground bounce noise[1], or delta-I noise, on the power/ground buses have become one of the major concerns during the design because of high-speed digital communication systems with even faster edge rates, lower voltage levels, and higher integrations.In the current scenario, PCB design level it’s major bottleneck for designers to mitigate noise in power plane resonance while suppressing the propagation of waves generated noise by the switching devices .Many Methods introduced in past works, in order to eliminate ground bounce noise, all try to reduce the resonance effects of the cavity-like structure. The most widely used and effective of them include the use of decoupling capacitors[4] , and capacitors , the use of dissipative and lossy components along the PCB and at its edges , dividing power planes in power islands , and via stitching[5] The use of decoupling capacitors is the most wide spread method and it consists of placing large capacitors around the sources of noise to disrupt high-frequency fluctuations on the power planes by creating a low-impedance path between the planes at these frequency. Other methods try to overcome this frequency limitation, in one way or another. Embedded capacitors and capacitances try to minimize the length of the problematic leads. Power islanding is also widely used, but its applicability is limited to applications in which isolation is the goal such that the source of noise and the susceptible components are kept on different power islands. EBG is one of the most promising solution to suppressed noise in mixed signal circuits. Earlier days Mushroom structure[6] are first proposed. this structure is specially designed via is inserted between power and ground planes, which make the fabrication cost is more effective. Later many planar structure is designed because of cost effective and fabrications cost is less. EBG planar structures proposed over the past few years have inherent features that make them important in EMI applications in mixed signal circuits.It’s create High Impedance surface(HIS).This is primarily due to the fact that EBG structures suppress the propagation of surface waves over a specific frequency band that directly depends on the dimensions and type of the constitutive elements within the EBG structures This paper proposed a novel structure to widen the band gap of EBG by introducing Meandered bridge instead of Lshaped bridges proposed in [7] and This paper compared the results of existing uniplanar compact EBG structure and modified structure The meandered bridge will reduce the lower edge of the bandgap to attain wide isolation bandwidth of the proposed structure. patch.The substrate dielectric is FR4 with a relative permittivity of 4.4 and a loss tangent of 0.02. The thickness of the substrate is 0.4mm and Metal conductor is PEC(Perfect electric conductor) with thickness is 0.017mm and corresponding parameters is Length and width(a) =29.6 mm Width of the meandered bridges(w1) =0.2mm,Length of the slit is(L) =7.25mm ,Width of the slit(W)=1.0mm,Gap between the two meandered lines(g)=0.75mm,Slit length(S)=4mm II. DESIGN OF MEANDERED EBG STRUCTURE WITH SLITS(MBS) A . Electromagnetic band gap (EBG) The EBG structure is behaves as distinctive properties in Microwave application and arranged in periodic structures(some cases as non-periodic), that materials may have not found in nature and Engineered made it artificially and altered the surface properties of the structure, EBG structure otherwise called as FSS(frequency selective surface),AMC(Artificial magnetic conductor) or HIS(high impedance surface ),PBG(photonic band gap structure).The properties of This structure is to restricts the propagation of electromagnetic waves in a forbidden band. Fig 1(a) shows in side view of EBG structure Fig 1(b) Unit cell of meandered bridge EBG with slits and dimensions Fig 1(a) Side view of EBG Structure B. Design concept The proposed EBG structure is a two-dimensional (2-D) structure, and consisting of a metal patch with four connecting meandered bridges, it can be realized with metal patches connected by meandered bridges to form a distributed LC network (where L is inductance and C is capacitance).The unit cell of this EBG structure is shown in Fig 1(b) The meandered bridges connecting the neighbouring unit cells will influence the inductance, while the patch and the gap between two neighbouring unit cells will induce the capacitance. Therefore, a higher inductance from effective increased meandered bridges will lead to more efficient lower edge. Meandered bridge EBG structure with slits(MBS) is proposed .It’s not only improve the inductance value but also supressed the noise at lower frequency. Dimensions of the slits and meandered bridges as properly designed to supressed the ground bounce noise in UWB Applications III. ULTRA WIDEBAND SUPPRESSIONS We considered a two layer PCB with dimensions of 64×64mm in 2×2 cells as shown in fig 1(b).The unit cell of the EBG as shown in fig 1(a). A power plane consists of one square patch with four narrow slits inserted at the boundary of the patch, and four meandered bridges on each side of the Fig 1(b) Modified Uniplanar compact EBG structure with meandered bridges and slits(MBS), Showing the location of the ports for s21 measurement Cases Parameter Reference board L-Bridgedwith slits Proposed(MB-EBG) -40 db suppressions Frequency Bandwidth none 750Mhz to 10Ghz 450Mhz to 10Ghz none 9.250Ghz 9.550Ghz Centre frequency at 5Ghz Isolation level -30db -60db thickness is 0.017mm and corresponding parameters is Length and width(a) =29.6 mm Width of the L bridges(w1) =0.2mm,Length of the slit is(L) =7.25mm ,Width of the slit(W)=1.0mm,Gap between the two bridges lines(g)=0.75mm,Slit length(S)=4mm TABLE I -110db SUPPRESSED BEHAVIOR BETWEEN PORT 1 AND PORT 2 COMPARISON Fig 2(a) simulation s21 of the proposed meandered bridge EBG Structure with slits(MBS) Fig 2(a) and Table I Shows comparison results of suppressed behaviour between port 1 and port 2. The reference board provides isolation of -30 dB over 1GHZ to 10GHZ and produces Unwanted anti-resonance, which is induced by GBN(Ground bounce noise) in PCB board circuits. The proposed MB-EBG( Meandered bridge) structure provides a bandgap of 450MHZ to 10 GHZ beyond for satisfied UWB applications and also suppressed the anti resonance which is provided by the reference board. By introducing of meandered bridge, the lower edge of the band gap is shifted towards the lower frequency.the proposed MBS-EBG structure provide a wide band gap compared to conventional L-EBG structure An ultra wideband supressions is observed at starts from 750mhz to 10 GHz. A proposed MBS-EBG power plane can suppress the GBN from lower frequency (450 MHz)to higher frequency (10 GHz), which can cover the whole UWB IV. CONCLUSIONS Fig 2(b) Comparison between L –bridged with slits(LBS) and proposed structure MBS-EBG structure In this paper, an efficient method for noise suppression of Ground bounce noise in UWB Applications using a Modified uniplanar compact EBG structure is designed in the chosen commercial software tools CST Microwave Studio to suppressed Ground bounce noise in ultra wide band(UWB) applications at frequency starts from 750MHZ to 10GHZ,isolation level below -40db is noted. By using meandered bridges in uniplanar compact EBG structure to improve good isolation level is observed at below -40db is observed and bandwidth covered from 450 MHZ to 10GHZ beyond. . REFERENCES Fig. 2(a) shows the simulated for the designed MBS-EBG power/ground planes. An ultra-wideband suppression is observed starting at approximately 450 MHz and extending to 10 GHz. The definition of bandwidth adopted here is the continuous frequency range over which S21 is lower than -40 dB.Compare with conventional UC(uniplanar compact)-EBG which has the same subtrates and 2 × 2 cells The substrate dielectric is FR4 with a relative permittivity of 4.4 and a loss tangent of 0.02. The thickness of the substrate is 0.4mm and Metal conductor is PEC(Perfect electric conductor) with [1] S. Van den Berghe, F. Olyslager, Member, IEEE, D. De Zutter, Senior Member, IEEE, J. De Moerloose, Member, IEEE, and W. Temmerman “Study of the Ground Bounce Caused by Power Plane Resonances” IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 40, NO. 2, MAY 1998 [2] Shahrooz Shahparnia, Student Member, IEEE, and Omar M. Ramahi, Senior Member, IEEE “.Electromagnetic Interference (EMI) Reduction From Printed Circuit Boards (PCB) Using Electromagnetic Bandgap Structures. 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