A Miniaturized Electromagnetic Bandgap Structure Using an Inductance-Enhanced Patch for Suppression of Parallel Plate Modes in Packages and PCBs

Myunghoi Kim

doi:10.3390/electronics7050076

Abstract

In the packages and printed circuit boards (PCBs) of high-speed and mixed-signal electronics, parallel plate waveguides (PPWs) are frequently used as the power/ground plane pair, resulting in a significant problem of electrical switching noise such as simultaneous switching noise and ground bounce noise. This noise inevitably deteriorates system performance. In this paper, we propose an electromagnetic bandgap (EBG) structure using an inductance-enhanced patch (IEP) to suppress PPW modes in high-speed and compact packages and PCBs. The noise suppression characteristics of the proposed IEP-EBG structure were thoroughly analyzed using a dispersion diagram based on a full-wave simulation as well as an equivalent circuit model of a unit cell structure with a Floquet boundary condition. The proposed IEP-EBG structure has the advantages of substantial reductions in the low cut-off frequency of the first stopband as well as unit cell size when compared to a conventional mushroom-type EBG structure without the inductance-enhanced technique. The suppression of the PPW modes of the proposed IEP-EBG structure was verified using measurements of scattering parameters. In the measurements, the low and high cut-off frequencies of the first stopband of the IEP-EBG structure were found to be 1.55 GHz and 2.48 GHz, respectively, while those of the conventional mushroom type EBG structure were 3.52 GHz and 5.3 GHz. For the low cut-off frequency, a 56% reduction was achieved, resulting in substantial miniaturization suitable for compact packages and PCBs.

Highlights

In current high-speed and mixed-signal electronics, the processor speed and communication data rate have been extremely increased to achieve massive computing platforms with high bandwidth data transfers
Structure, test vehicles (TVs) were fabricated using commercial printed circuit boards (PCBs) manufacturing process with a plated through hole (PTH)
An inductance-enhanced patch (IEP) technique was presented that efficiently miniaturized the electromagnetic bandgap (EBG) structure while suppressing the parallel plate waveguides (PPWs) modes in high-speed packages and PCBs

Summary

Introduction

In current high-speed and mixed-signal electronics, the processor speed and communication data rate have been extremely increased to achieve massive computing platforms with high bandwidth data transfers. Consumer electronics such as mobile phones and tablet PCs possess a CPU with several giga-hertz (GHz) clock speeds and a serial communication device with multi-giga byte per second (GBps) data rates. The significant increases in switching speeds and data rates induce a wideband switching noise called simultaneous switching noise (SSN) or ground bounce noise (GBN). The SSN characteristics of wideband bandwidth and high frequency harmonics allow it to be coupled to signal lines, which results in signal waveform distortion, low bit error rate (BER), and low reliability. Numerous studies have focused on suppressing the parallel plate waveguide (PPW) modes in packages and PCBs because SSN is mainly generated when a switching device excites a PPW, Electronics 2018, 7, 76; doi:10.3390/electronics7050076 www.mdpi.com/journal/electronics

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