740 IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 8, 2009 Ultrawideband Suppression of Ground Bounce Noise in Multilayer PCB Using Locally Embedded Planar Electromagnetic Band-Gap Structures Long Li, Member, IEEE, Qiang Chen, Member, IEEE, Qiaowei Yuan, and Kunio Sawaya, Senior Member, IEEE Abstract—A novel uniplanar compact electromagnetic band-gap (EBG) structure is proposed for ultrawideband (UWB) suppres- sion of ground bounce noise (GBN) in multilayer PCB. The power plane integrates the features of L-shaped bridges and slits (LBS), which can suppress the GBN at lower and higher frequencies, respectively, without using hybrid periods cascading structures. The GBN suppression bandwidth is broadened from 432 MHz to 15 GHz covering almost the whole noise band for UWB applica- tions. A locally embedded LBS-EBG structure in power plane is proposed to improve signal integrity (SI). Full-wave simulation and measurement are performed to verify the high performance. Index Terms—Electromagnetic band-gap (EBG), ground bounce noise (GBN), locally embedded, multilayer printed circuit board (PCB), signal integrity. I. INTRODUCTION W ITH the trends of mix-signal system integration, high- speed microprocessors, radio frequency (RF) circuits, memory, sensors, and optical devices, etc., are required to be integrated into a tight module, which is known as “system on package”. The ground bounce noise (GBN) [1], also known as simultaneous switching noise (SSN), on the power/ground planes is becoming one of the major bottleneck for designing the high-speed circuits in multilayer printed circuit board (PCB). As the systems operate toward higher frequency range, the GBN will excite the resonance modes of the parallel-plate waveguide structure between power and ground planes, which behave as radial waves and travel outwards from noise source to the edges of circuit board. Some portion of the energy is reflected in- wards affecting the signal integrity (SI) and some part is radiated into free-space causing the electromagnetic interference (EMI) problems [2]. Especially in ultrawideband (UWB) communica- tion technology, since the maximum signal power is limited to a very low level, any noise from digital circuits could destroy the functionality of RF circuits and cause system failure. Manuscript received August 05, 2008; revised October 25, 2008. First pub- lished November 17, 2008; current version published July 28, 2009. This work is supported in part by the National Natural Science Foundation of China under Contract 60601028 and by the JSPS Postdoctoral Fellowship of Japan. L. Li was with Tohoku University, Sendai, 980-8579, Japan. He is now with the School of Electronic Engineering, Xidian University, Xi’an, 710071, China (e-mail: lilong@mail.xidian.edu.cn; lilong@ecei.tohoku.ac.jp). Q. Chen, Q. Yuan, and K. Sawaya are with the Department of Electrical and Communication Engineering, Tohoku University, Sendai, 980-8579, Japan (e-mail: chenq@ecei.tohoku.ac.jp; qwyuan@ecei.tohoku.ac.jp; sawaya@ecei. tohoku.ac.jp). Color versions of one or more of the figures in this letter are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/LAWP.2008.2009363 Some typical ways [3], such as adding decoupling capacitors, splitting the power and/or ground planes, and using the isolation moat, have been proposed to eliminate the GBN, but they are not effective above 1 GHz. Recently, a new idea for eliminating the GBN was introduced by using electromagnetic band-gap (EBG) structures [4], [5]. There are many researches focused on EBG structure design to broaden the stopband for high efficient GBN suppression [6]–[11]. In this letter, a novel uniplanar compact EBG structure which integrates L-bridged EBG structure with slits is proposed for ultra-wideband GBN suppression in multilayer PCB. The GBN suppression bandwidth is broadened to cover from 432 MHz to 15 GHz without using cascading different period structures. To improve the SI, a locally embedded EBG structure in power plane is used. -parameters for multiport network and -field distribution on each layer are investigated. The distinctive be- havior of the new EBG power plane in ultra-wideband suppres- sion of the GBN is validated by simulations and measurements. II. DESIGN OF NEW L-BRIDGED EBG STRUCTURE WITH SLITS To filter out GBN propagating within the power/ground planes while providing a low-impedance path for DC current on each layer, a two-layer EBG embedded power plane struc- ture is used, and the ground plane is kept continuous for SI view. Fig. 1(a) shows the proposed L-shaped bridges with slits (LBS) EBG power/ground planes design. The unit cell of the EBG power plane consists of one square patch with four narrow slits inserted at the boundary of the patch, and four L-shaped bridges on each side of the patch [11]. The unit cell of the LBS-EBG and its corresponding notations of parameters are shown in Fig. 1(b). The key feature of this new structure is an integration of L-bridges with slits. Compared to the traditional UC-EBG struc- ture with straight bridges [5], the L-shaped bridges not only improve the inductance between two neighboring patches so that they can suppress the noise at lower frequencies, but also keep signal quality acceptably well [6]. Compared to the pre- vious L-bridged EBG structures, the narrow slits inserted at the boundary of the patch change the flow paths of currents. Due to the slits perturbation, the resonant mode of the square patch will be split so that they can suppress the noise at higher frequencies. As a result, the geometry of the slit and bridge can be designed properly based on the requirement of suppression bandwidth. III. ULTRAWIDEBAND GBN SUPPRESSION To demonstrate the effectiveness of the LBS-EBG power plane, we consider a design of a two-layer PCB with the dimension 90 mm 150 mm consisting of 3 5 unit cells. 1536-1225/$26.00 © 2009 IEEE Authorized licensed use limited to: TOHOKU UNIVERSITY. Downloaded on August 6, 2009 at 22:36 from IEEE Xplore. Restrictions apply.