Electromagnetic Bandgap Structure For Isolation In Mixed-signal Systems

Electromagnetic bandgap (EBG) structures, systems incorporating EBG structures, and methods of making EBG structures, are disclosed. An embodiment of the structure, among others, includes a plurality of first elements disposed on a first plane of a device; and a second element connecting each first element to an adjacent first element, the second element being disposed on the first plane of the device. The structure is configured to substantially filter electromagnetic waves to a stopband floor of about -40 dB to about -120 dB in a bandgap of about 100 MHz to about 50 GHz having a width selected from about 1 GHz, 2 GHz, 3 GHz, 5 GHz, 10 GHz, 20 GHz, and 30 GHz. In addition, the structure has a center frequency positioned at a frequency from about 1 GHz to 37 GHz.Georgia Tech Research Corporatio

Complementary spiral resonators for ultrawideband suppression of simultaneous switching noise in high-speed circuits

Cataloged from PDF version of article.In this paper, a novel concept for ultra-wideband simultaneous switching noise (SSN) mitigation in high-speed printed circuit boards (PCBs) is proposed. Using complementary spiral resonators (CSRs) etched on only a single layer of the power plane and cascaded co-centrically around the noise port, ultra-wideband SSN suppression by 30 dB is achieved in a frequency span ranging from 340 MHz to beyond 10 GHz. By placing a slit in the co-centric rings, lower cut-off frequency is reduced to 150 MHz, keeping the rest of the structure unaltered. Finally, the power plane structure with modified complementary spiral resonators (MCSRs) is designed, fabricated, and evaluated experimentally. Measurement and simulation results are in well-agreement

A bandwidth enhanced multilayer electromagnetic bandgap structure to reduce the simultaneous switching noise

A bandwidth enhanced multilayer Electromagnetic Band Gap (EBG) structure to reduce the simultaneous switching noise (SSN) in high frequency operating circuits, which useful for the satellite communication application, is presented in this paper. A proposed stack structure is mathematically analyzed by the dispersion method and transmission matrix method. Simulation results show good mitigation of SSN in scattering parameters and signal integrity in terms of eye diagrams. We have also checked for power integrity analysis using self-impedance. The proposed structure gives a good SSN suppression at -30 dB from 817 MHz to 26.32 GHz, around 25.50 GHz bandwidth and also reduces the cavity mode resonance within the stopband range. The proposed multilayer structure is compared with planar EBG plane and reference board. It is also compared with published results

ELECTROMAGNETIC BANDGAP STRUCTURES FOR BROADBAND SWITCHING NOISE MITIGATION IN HIGH-SPEED PACKAGES

For the past two decades, silicon-based complementary metal-oxide semiconductor (CMOS) technology and circuits have been advancing along an exponential path of shrinking device dimensions, increasing density, increasing speed, and decreasing cost. Electronic design complexity is in constant acceleration and new designs have to incorporate new features, which inevitably will require faster processing time. In recent years this acceleration rate has drastically decreased because of various constraints, such as static power dissipation due to leakage current, the effect of wires and interconnects and the decreased immunity of modern devices to noise, interference and voltage fluctuations on their Power Distribution Network (PDN). Lowering the power supply voltages and hence the power consumption of a single transistor, has been possible due to the fact that these new technologies are able to provide smaller and faster transistors with lower threshold levels. The benefits associated with lowering the threshold levels of the transistors used in a given device comes at a high-price, specifically the decrease of immunity of such device to noise and fluctuations of the power supply voltage. The research work carried out in this dissertation, addresses the concept of embedding Electromagnetic Bandgap (EBG) structures in conventional power distribution networks in order to increase the immunity of the circuits that feed from such networks to noise and voltage fluctuations. Underlying theories of Embedded EBG (EEBG) structures and design methodologies are presented. Various design concepts, based on simulations, measurements and different modeling techniques developed during this research work are presented. The accuracy of these methods is analyzed by comparing results of these techniques with experimental results. Also, this work shows that EEBG structures are not only very effective in the suppression of switching noise in high-speed circuit but also they suppress Electromagnetic Interference (EMI) caused by such switching and they provide increased immunity for their PDN to external sources of noise. Finally new EEBG configurations, topologies and miniaturized structures are introduced that overcome the limitations of current switching noise mitigation techniques, including initial EEBG designs to provide immunity against high-bandwidth noise, voltage fluctuations and radiation, new EEBG configurations, topologies and miniaturized structures are introduced and their efficacy is demonstrated. The novel designs developed during this research provide noise mitigation over a wide range of frequencies, and also extends the suppression frequency range into the sub-gigahertz region, only using a single EBG design with smaller patches than those used in previous works

Electromagnetic interference reduction in printed circuit boards by using metamaterials: a conduction and radiation impact analysis

This work aims to compare the implementation of two metamaterials for reducing electromagnetic interference (EMI) in printed circuit boards. Specifically, complementary split-ring resonators (CSRRs) and electromagnetic bandgaps (EBGs) were etched on the ground plane of a microstrip transmission line. Both techniques were compared as EMI filters, taking into account frequency response, signal integrity, and near- and far-field radiation with regard to a reference (solid ground) board. The results of electromagnetic simulations and experimental tests show similar EMI rejection levels in both cases, but CSRRs have a significantly better signal integrity response whereas EBGs behave as lower electromagnetic radiation elements in the operation frequency band.Peer ReviewedPreprin

HIGH-IMPEDANCE ELECTROMAGNETIC SURFACES FOR MITIGATION OF SWITCHING NOISE IN HIGH-SPEED CIRCUITS

With the increasing gate density, the rising clock frequency, printed circuit board (PCB) level simultaneous switching noise (SSN) has become a major bottleneck for the signal integrity in high-speed microprocessors and computers. All approaches that are currently being used to address this problem have been proven inefficient for switching frequencies of 500 MHz and above. The research work carried out in this dissertation addresses a novel technique for mitigating high-frequency SSN by suppressing the natural parallel-plate resonant modes encountered in traditional power planes. This is done by replacing at least one of the power planes of the power distribution network with a high-impedance electromagnetic surface (HIS). The high-impedance electromagnetic surface, which indeed is an artificial magnetic conductor, prevents any surface wave propagation in its forbidden band-gap, therefore leading to the suppression of resonant modes. Using full wave electromagnetic simulation and experimental verification, the fundamental limitations of SSN mitigation using standard HIS is investigated. It is found that the thickness of the dielectric substrate and the metal line spacing offered by most PCB technologies are fundamental limitations for achieving broadband simultaneous switching noise mitigation at frequencies below 3 GHz for high-density packaging. This restriction is addressed by developing a new family of HIS, whose surface impedance is mainly controlled by the inductance density. These novel inductively-tuned HIS offer the possibility of mitigating switching noise at frequencies of 1 GHz and below frequencies and can be fabricated using conventional PCB technology. It is also demonstrated that the combination of these novel HIS with RC dissipative edge termination (DET) leads to broadband simultaneous switching noise mitigation from DC to about 3 or 4 GHz. Finally physics-based compact models that allow the use of the novel power planes with other components for full package simulation are developed and validated for power planes with integrated standard and double-layer HIS. These models utilize only frequency independent lumped-components and are, therefore, particularly attractive for transient analysis

Metamaterials for Decoupling Antennas and Electromagnetic Systems

This research focuses on the development of engineered materials, also known as meta- materials, with desirable effective constitutive parameters: electric permittivity (epsilon) and magnetic permeability (mu) to decouple antennas and noise mitigation from electromagnetic systems. An interesting phenomenon of strong relevance to a wide range of problems, where electromagnetic interference is of concern, is the elimination of propagation when one of the constitutive parameters is negative. In such a scenario, transmission of electromagnetic energy would cease, and hence the coupling between radiating systems is reduced. In the first part of this dissertation, novel electromagnetic artificial media have been developed to alleviate the problem of mutual coupling between high-profile and ow-profile antenna systems. The developed design configurations are numerically simulated, and experimentally validated. In the mutual coupling problem between high-profile antennas, a decoupling layer based on artificial magnetic materials (AMM) has been developed and placed between highly-coupled monopole antenna elements spaced by less than Lambda/6, where Lambda is the operating wavelength of the radiating elements. The decoupling layer not only provides high mutual coupling suppression (more than 20-dB) but also maintains good impedance matching and low correlation between the antenna elements suitable for use in Multiple-Input Multiple-Output (MIMO) communication systems. In the mutual coupling problem between low-profile antennas, novel sub-wavelength complementary split-ring resonators (CSRRs) are developed to decouple microstrip patch antenna elements. The proposed design con figuration has the advantage of low-cost production and maintaining the pro file of the antenna system unchanged without the need for extra layers. Using the designed structure, a 10-dB reduction in the mutual coupling between two patch antennas has been achieved. The second part of this dissertation utilizes electromagnetic artificial media for noise mitigation and reduction of undesirable electromagnetic radiation from high-speed printed-circuit boards (PCBs) and modern electronic enclosures with openings (apertures). Numerical results based on the developed design configurations are presented, discussed, and compared with measurements. To alleviate the problem of simultaneous switching noise (SSN) in high-speed microprocessors and personal computers, a novel technique based on cascaded CSRRs has been proposed. The proposed design has achieved a wideband suppression of SSN and maintained a robust signal integrity performance. A novel use of electromagnetic bandgap (EBG) structures has been proposed to mitigate undesirable electromagnetic radiation from enclosures with openings. By using ribbon of EBG surfaces, a significant suppression of electromagnetic radiation from openings has been achieved

Planar electromagnetic bandgap structures based on polar curves and mapping functions

A type of electromagnetic bandgap structure is described that is easily parameterized and can produce a range of square and spiral geometries. Individual electromagnetic bandgap (EBG) geometries are defined on a cell-by-cell basis in terms of their convolution factor , which defines the extent to which the elements are interleaved and controls the coupling slot length between adjacent elements. Polar equations are used to define the slot locus which also incorporate a transformation which ensures the slot extends into the corners of the square unit cell and hence extends the maximum slot length achievable. The electromagnetic properties of the so-called polar EBG are evaluated by means of numerical simulation and measurements and dispersion diagrams are presented. Finally, the performance is compared with other similar miniaturized EBG cell geometries. It is shown that the polar EBG has better angular stability than the equivalent square patch design and is comparable in terms of performance to other low frequency EBG elements. At the same time it retains the ability to fine tune the response by adjusting

Electromagnetic Interference Reduction using Electromagnetic Bandgap Structures in Packages, Enclosures, Cavities, and Antennas

Electromagnetic interference (EMI) is a source of noise problems in electronic devices. The EMI is attributed to coupling between sources of radiation and components placed in the same media such as package or chassis. This coupling can be either through conducting currents or through radiation. The radiation of electromagnetic (EM) fields is supported by surface currents. Thus, minimizing these surface currents is considered a major and critical step to suppress EMI. In this work, we present novel strategies to confine surface currents in different applications including packages, enclosures, cavities, and antennas. The efficiency of present methods of EM noise suppression is limited due to different drawbacks. For example, the traditional use of lossy materials and absorbers suffers from considerable disadvantages including mechanical and thermal reliability leading to limited life time, cost, volume, and weight. In this work, we consider the use of Electromagnetic Band Gap (EBG) structures. These structures are suitable for suppressing surface currents within a frequency band denoted as the bandgap. Their design is straight forward, they are inexpensive to implement, and they do not suffer from the limitations of the previous methods. A new method of EM noise suppression in enclosures and cavity-backed antennas using mushroom-type EBG structures is introduced. The effectiveness of the EBG as an EMI suppresser is demonstrated using numerical simulations and experimental measurements. To allow integration of EBGs in printed circuit boards and packages, novel miniaturized simple planar EBG structures based on use of high-k dielectric material (r > 100) are proposed. The design consists of meander lines and patches. The inductive meander lines serve to provide current continuity bridges between the capacitive patches. The high-k dielectric material increases the effective capacitive load substantially in comparison to commonly used material with much lower dielectric constant. Meander lines can increase the effective inductive load which pushes down the lower edge of bandgap, thus resulting in a wider bandgap. Simulation results are included to show that the proposed EBG structures provide very wide bandgap (~10GHz) covering the multiple harmonics of of currently available microprocessors and its harmonics. To speed up the design procedure, a model based on combination of lumped elements and transmission lines is proposed. The derived model predicts accurately the starting edge of bandgap. This result is verified with full-wave analysis. Finally, another novel compact wide band mushroom-type EBG structure using magneto-dielectric materials is designed. Numerical simulations show that the proposed EBG structure provides in-phase reflection bandgap which is several times greater than the one obtained from a conventional EBG operating at the same frequency while its cell size is smaller. This type of EBG structure can be used efficiently as a ground plane for low-profile wideband antennas

Laajakaistaisen sähkömagneettisen kohinan vaimentaminen piirilevyissä

Tietoliikenteen laitteiden kehityksessä on havaittavissa yhteisiä tekijöitä kuten alati kasvava kellotaajuus, pienenevä laitteen koko ja alenevat jännitetasot. Tämä kehityssuunta asettaa uusia vaatimuksia systeemin sähkömagneettiselle yhteensopivuudelle ja korostaa piirilevyn ominaisuuksien tärkeyttä. Samanaikaiset pulssisignaalit komponentin porteista saavat aikaan sähkömagneettista säteilyä tehonjakelutasoissa, joka on otettava huomioon piirilevyn pinnan lisäksi. Tulevissa standardeissa laitteille on asetettu rajoja jo useille gigahertseille asti. Perinteiset kohinan eristyskeinot kuten oikosulkukondensaattorit ja jaetut tehotasot eivät tarjoa ratkaisua korkeilla taajuuksilla. Muut vaihtoehdot kuten korkean permeabiliteetin väliaineet tai absorboivat materiaalit ovat taas kalliita massavalmistukseen. Metamateriaalit ovat kompleksinen materiaaliluokka, joille on yhteistä että niiden sähkömagneettiset ominaisuudet saavutetaan imitoimalla materiaalin mikroskooppista rakennetta makroskooppisella rakenteella. Sähkömagneettinen kaistanesto (Engl. EBG) on metamateriaalityyppi, joka vaimentaa sähkömagneettisia aaltoja rakenteen jaksoon verrannollisella aallonpituusalueella. Laajakaistaisen kohinan vaimentamiseen soveltuu kaksi rakenteen kehityssuuntaa; sieni-tyyppi ja planaari-tyyppi. Tämä työ esittelee ja analysoi rakenteita, joita on esitetty molempien kehityshaarojen julkaisuissa. Planaari-tyyppi tarjoaa ohuemman rakenteen, mutta samalla se vaatii apertuurien tekemistä tehonjakelutasoon, rajoittaa siirrettävän tehon määrää sekä vie laajan pinta-alan piirilevyltä. Näin ollen, työssä päädytään sieni-tyypin valintaan jatkotutkimukselle. Ensimmäisen yhdestä läpiviennistä ja johdintasosta koostuvan sieni-tyypin julkaisun jälkeen on julkaistu versioita useilla läpivienneillä estokaista kasvattamiseksi. Tässä työssä tutkitaan sieni-rakennetta neljällä läpiviennillä simuloinneilla sekä analyyttisin mallein. Tulokset osoittavat että rakenteen toiminta perustuu bi-periodisiin virtasilmukoihin, joista joka toisessa on kapasitiivinen kuorma. Täten rakenteen dispersio poikkeaa merkittävästi yhden läpiviennin sienirakenteesta ja siinä on useita resonanssipisteitä tehden rakenteesta laajakaistaisen. Läpivientien paikkaa säätämällä voidaan säätää estokaistan ominaisuuksia. Tulokset osoittavat, että yhden läpiviennin sieni-rakenne on neljän läpiviennin rakenteen erikoistapaus. Asettamalla läpiviennit salmiakkikuvioon neliön sijaan, huomattiin estokaistanleveyden kasvu kohtisuoran aallon tapauksessa. Työssä tehtiin testipiirilevy, jota mittaamalla selvitettiin rakenteen jaksojen lukumäärän vaikutusta saavutettavaan vaimennukseen. Jo yhdellä rivillä saavutettiin korkea vaimennus ja täysi estokaista neljällä rivillä