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1
Palreddy, Sandeep R. "Wideband Electromagnetic Band Gap (EBG) Structures, Analysis and Applications to Antennas." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/54004.
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In broadband antenna applications, the antenna's cavity is usually loaded with absorbers to eliminate the backward radiation, but in doing so the radiation efficiency of the antenna is decreased. To enhance the radiation efficiency of the antennas EBG structures are used, but they operate over a narrow band. Uniform electromagnetic band gap (EBG) structures are usually periodic structures consisting of metal patches that are separated by small gaps and vias that connect the patches to the ground plane. The electrical equivalent circuit consists of a resonant tank circuit, whose capacitance is represented by the gap between the patches and inductance represented by the via. EBG structures are equivalent to a magnetic surface at the frequency of resonance and thus have very high surface impedance; this makes the EBG structures useful when mounting an antenna close to conducting ground plane, provided the antenna's currents are parallel to the EBG structure. Because EBG structures are known to operate over a very narrow band, they are not useful when used with a broadband antenna. Mushroom-like uniform EBG structures (that use vias) are compact in size have low loss, can be integrated into an antenna to minimize coupling effects of ground planes and increase radiation efficiency of the antenna. The bandwidth of an EBG structure is defined as the band where the reflection-phase from the structure is between +900 to -900. In this dissertation analysis of EBG structures is established using circuit analysis and transmission line analysis. Methods of increasing the bandwidth of EBG structures are explored, by cascading uniform EBG structures of different sizes progressively and vertically (stacked), and applications with different types of antennas are presented. Analyses in this dissertation are compared with previously published results and with simulated results using 3D electromagnetic tools. Validation of applications with antennas is carried by manufacturing prototypes and comparing measured performance with analysis and 3D electromagnetic simulations. The improvements in performance by using wideband progressive EBG and wideband stacked EBG structures are noted.Ph. D.
2
Chauraya, Alford. "Photoconductive switching using silicon and its applications in antennas and reconfigurable metallodielectric Electromagnetic Band Gap (EBG) structures." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/34254.
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The aims of this research work were to investigate the microwave properties of photoconductive semiconductor switches (PCSS), and how the properties might be used to optically control microwave and millimetre wave devices. Tunable devices (such as antennas, filters and metamaterials) have the ability to increase flexibility performance in multiband systems for example. In this thesis the performance of microwave switches from microstrip discontinuities, with high resistivity silicon dice placed cross the gaps were investigated. Under optical illumination, the electrons in silicon can be excited from the valence band to the conduction band. This photoconductivity in silicon has been employed to design a small microwave switch that can be operated using optical signal. The optically activated switch offers a wide range of applications. Potential applications have been demonstrated in integrating the microswitch in microstrip patch antenna, microstrip couple line filter, and Electromagnetic Band Gap (EBG) structures.
3
Saleh, Gameel [Verfasser], Klaus [Akademischer Betreuer] Solbach, and Daniel [Akademischer Betreuer] Erni. "High Impedance Surface – Electromagnetic Band Gap (HIS-EBG) Structures for Magnetic Resonance Imaging (MRI) Applications / Gameel Saleh. Gutachter: Daniel Erni. Betreuer: Klaus Solbach." Duisburg, 2013. http://d-nb.info/104601157X/34.
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Kambisseri, Roby Neelu. "Wireless communication using metasurfaces for condition monitoring in motor." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-246051.
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Wireless sensors are used widely for condition monitoring in electric machines. The metal enclosure of an electric motor restricts the signal from sensors to radiate outside. The signal from the metal cavity needs to be guided to the only opening in the enclosure, through a narrow gap between the stator and the rotating rotor. Gap waveguide technology is proposed as a solution by texturing the stator surface with electromagnetic band gap (EBG) structures. Arrays of periodic holey structures are used to realize the metasurface waveguide. Two Bravais lattice structures – square and hexagonal, are explored for guiding waves along a desired path in a parallel plate waveguide. Simulations are carried out to study the influence of various dimensions of the unit cells. A waveguide with hexagonal hole-type unitcell is designed and manufactured for experimental verification. The possibility of extending the same technology to cylindrical surface is confirmed by simulations.Trådlösa sensorer används allmänt för tillståndsövervakning i elektriska maskiner. Metallhöljet hos en elektrisk motor begränsar signalen från sensorerna från att stråla utåt. Signalen från metallhåligheten behöver styras till den enda öppningen i höljet, genom ett smalt mellanrum mellan statorn och den roterande rotorn. Gap-vågledarteknik föreslås som en lösning genom att strukturera statorytan med elektromagnetiska bandgap-strukturer (EBG). Arrayer av periodiskt håliga strukturer används för att realisera metayt-vågledare. Två Bravais gitterkonstruktioner –kvadratiska och sexkantiga, undersöks för styrning av vågor längs en önskad väg i en parallellplattvågledare. Simuleringar utförs för att studera påverkan av olika dimensioner hos enhetscellerna. En vågledare med hexagonal håltypsenhetscell är konstruerad och tillverkad för experimentell verifiering. Möjligheten att utvidga samma teknik till cylindrisk yta bekräftas genom simuleringar.
5
Pítra, Kamil. "Antény pro oblasti (sub)milimetrových vln." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-233662.
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Disertační práce se zabývá návrhem a optimalizací kruhově polarizované anténa pro oblast terahertzových kmitočtů. V práci se věnuji zjednodušené teorii terahertzového zdroje a návrhu vhodné antény pro tento zdroj. Návrh je zaměřen na dosažení kruhové polarizace z lineárně polarizovaných antén. Abych potlačil šíření povrchové vlny na elektricky tlustém dielektrickém substrátu, věnuji se návrhu a optimalizaci specifických periodických struktur. Návrh těchto struktur je poměrně komplikovaný, protože neexistuje přímočarý vztah mezi vlastnostmi struktur s elektromagnetickým zádržným pásmem (EBG) a geometrií buňky. Abych vhodně koncentroval vyzařovanou energii do úzkého svazku, věnuji se návrhu a optimalizaci částečně odrazného plochy (PRS), které působí jako planární čočka pro terahertzovou anténu.
6
Abidin, Z. Z. "Design, modelling and implementation of antennas using electromagnetic bandgap material and defected ground planes. Surface Meshing Analysis and Genetic Algorithm Optimisation on EBG and Defected Ground Structures for Reducing the Mutual Coupling between Radiating Elements of Antenna Array and MIMO Systems." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5385.
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The main objective of this research is to design, model and implement several antenna
geometries using electromagnetic band gap (EBG) material and a defected ground
plane. Several antenna applications are addressed with the aim of improving
performance, particularly the mutual coupling between the elements.
The EBG structures have the unique capability to prevent or assist the propagation of
electromagnetic waves in a specific band of frequencies, and have been incorporated
here in antenna structures to improve patterns and reduce mutual coupling in multielement
arrays. A neutralization technique and defected ground plane structures have
also been investigated as alternative approaches, and may be more practical in real
applications.
A new Uni-planar Compact EBG (UC-EBG) formed from a compact unit cell was
presented, giving a stop band in the 2.4 GHz WLAN range. Dual band forms of the
neutralization and defected ground plane techniques have also been developed and
measured. The recorded results for all antenna configurations show good improvement
in terms of the mutual coupling effect.
The MIMO antenna performance with EBG, neutralization and defected ground of
several wireless communication applications were analysed and evaluated. The
correlation coefficient, total active reflection coefficient (TARC), channel capacity and
capacity loss of the array antenna were computed and the results compared to
measurements with good agreement.
In addition, a computational method combining Genetic Algorithm (GA) with surface
meshing code for the analysis of a 2×2 antenna arrays on EBG was developed. Here the
impedance matrix resulting from the meshing analysis is manipulated by the GA
process in order to find the optimal antenna and EBG operated at 2.4 GHz with the goal
of targeting a specific fitness function. Furthermore, an investigation of GA on 2×2
printed slot on DGS was also done.Ministry of Higher Education Malaysia and Universiti Tun Hussein Onn Malaysia (UTHM)
7
Abidin, Zuhairiah Zainal. "Design, modelling and implementation of antennas using electromagnetic bandgap material and defected ground planes : surface meshing analysis and genetic algorithm optimisation on EBG and defected ground structures for reducing the mutual coupling between radiating elements of antenna array MIMO systems." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5385.
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The main objective of this research is to design, model and implement several antenna geometries using electromagnetic band gap (EBG) material and a defected ground plane. Several antenna applications are addressed with the aim of improving performance, particularly the mutual coupling between the elements. The EBG structures have the unique capability to prevent or assist the propagation of electromagnetic waves in a specific band of frequencies, and have been incorporated here in antenna structures to improve patterns and reduce mutual coupling in multielement arrays. A neutralization technique and defected ground plane structures have also been investigated as alternative approaches, and may be more practical in real applications. A new Uni-planar Compact EBG (UC-EBG) formed from a compact unit cell was presented, giving a stop band in the 2.4 GHz WLAN range. Dual band forms of the neutralization and defected ground plane techniques have also been developed and measured. The recorded results for all antenna configurations show good improvement in terms of the mutual coupling effect. The MIMO antenna performance with EBG, neutralization and defected ground of several wireless communication applications were analysed and evaluated. The correlation coefficient, total active reflection coefficient (TARC), channel capacity and capacity loss of the array antenna were computed and the results compared to measurements with good agreement. In addition, a computational method combining Genetic Algorithm (GA) with surface meshing code for the analysis of a 2×2 antenna arrays on EBG was developed. Here the impedance matrix resulting from the meshing analysis is manipulated by the GA process in order to find the optimal antenna and EBG operated at 2.4 GHz with the goal of targeting a specific fitness function. Furthermore, an investigation of GA on 2×2 printed slot on DGS was also done.
8
Lancaster, Greg A. "A Tunable Electromagnetic Band-gap Microstrip Filter." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/952.
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In high frequency design, harmonic suppression is a persistent struggle. Non-linear devices such as switches and amplifiers produce unwanted harmonics which may interfere with other frequency bands. Filtering is a widely accepted solution, however there are various shortcomings involved. Suppressing multiple harmonics, if desired, with traditional lumped element and distributed component band-stop filters requires using multiple filters. These topologies are not easily made tunable either. A new filter topology is investigated called Electromagnetic Band-Gap (EBG) structures.
EBG structures have recently gained the interest of microwave designers due to their periodic nature which prohibits the propagation of certain frequency bands. EBG structures exhibit characteristics similar to that of a band-stop filter, but in periodically repeating intervals making it ideal for harmonic suppression. The band-gap frequency of an EBG structure may be varied by altering the periodicity of the structure. However, EBG materials are generally static in structure making tuning a challenge.
In this thesis, a novel solution for tuning the band-gap properties of an EBG structure is investigated. Designs aimed to improve upon existing solutions are reached. These designs involve acoustic and mechanical tuning methods. Performance is simulated using Agilent’s Advanced Design System (ADS) and a device is constructed and evaluated. Comparing all measured test cases to simulation, band-gap center frequency error is on average 4.44% and absolute band-gap rejection error is 1.358 dB.
9
Gao, Bo. "Passive UHF RFID tag using electromagnetic band gap (EBG) material for metallic objects tracking /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?MECH%202007%20GAO.
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Kim, Tae Hong. "Electromagnetic Band Gap (EBG) synthesis and its application in analog-to-digital converter load boards." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/22712.
Full textAbstract:
With increase in frequency and convergence toward mixed signal systems, supplying stable voltages to integrated circuits and blocking noise coupling in the systems are major problems. Electromagnetic band gap (EBG) structures have been in the limelight for power/ground noise isolation in mixed signal applications due to their capability to suppress unwanted electromagnetic mode transmission in certain frequency bands. The EBG structures have proven effective in isolating the power/ground noise in systems that use a common power supply. However, while the EBG structures have the potential to present many advantages in noise suppression applications, there is no method in the prior art that enables reliable and efficient synthesis of these EBG structures.
Therefore, in this research, a novel EBG synthesis method for mixed signal applications is presented. For one-dimensional periodic structures, three new approaches such as current path approximation method, border to border radius, power loss method have been introduced and combined for synthesis. For two-dimensional EBG structures, a novel EBG synthesis method using genetic algorithm (GA) has been presented. In this method, genetic algorithm (GA) is utilized as a solution-searching technique. Synthesis procedure has been automated by combining GA with multilayer finite-difference method and dispersion diagram analysis method. As a real application for EBG structures, EBG structures have been applied to a GHz ADC load board design for power/ground noise suppression.
11
Slavíček, Radek. "Návrh periodických struktur pro zvýšení směrovosti dielektrických rezonátorových antén." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377333.
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The thesis deals with linearly polarized dielectric rectangular resonator antenna (DRA) operating in the basic mode TEy11 and higher order mode TEy131 at f0 = 10GHz surrounded by an electromagnetic band gap structure (EBG). The dielectric resonator antennas, the EBG structure were designed and a method of integration of both components was developed. The simulated results show a significant improvement of the radiation pattern in the E-plane radiation pattern (narrower main beam, lower level of side lobes, higher directivity) in comparison to a conventional DRA. This was verified by the TEy11 measurement.
12
Guo, Yunchuan. "Analysis and design of novel electromagnetic metamaterials." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/7864.
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This thesis introduces efficient numerical techniques for the analysis of novel electromagnetic metamaterials. The modelling is based on a Method of Moments modal analysis in conjunction with an interpolation scheme, which significantly accelerates the computations. Triangular basis functions are used that allow for modelling of arbitrary shaped metallic elements. Unlike the conventional methods, impedance interpolation is applied to derive the dispersion characteristics of planar periodic structures. With these techniques, the plane wave and the surface wave responses of fractal structures have been studied by means of transmission coefficients and dispersion diagrams. The multiband properties and the compactness of the proposed structures are presented. Based on this method, novel planar left-handed metamaterials are also proposed. Verifications of the left-handedness are presented by means of full wave simulation of finite planar arrays using commercial software and lab measurement. The structures are simple, readily scalable to higher frequencies and compatible with low-cost fabrication techniques.
13
Govind, Vinu. "Design of Baluns and Low Noise Amplifiers in Integrated Mixed-Signal Organic Substrates." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7208.
Full textAbstract:
The integration of mixed-signal systems has long been a problem in the semiconductor industry. CMOS System-on-Chip (SOC), the traditional means for integration, fails mixed-signal systems on two fronts; the lack of on-chip passives with high quality (Q) factors inhibits the design of completely integrated wireless circuits, and the noise coupling from digital to analog circuitry through the conductive silicon substrate degrades the performance of the analog circuits. Advancements in semiconductor packaging have resulted in a second option for integration, the System-On-Package (SOP) approach. Unlike SOC where the package exists just for the thermal and mechanical protection of the ICs, SOP provides for an increase in the functionality of the IC package by supporting multiple chips and embedded passives. However, integration at the package level also comes with its set of hurdles, with significant research required in areas like design of circuits using embedded passives and isolation of noise between analog and digital sub-systems.
A novel multiband balun topology has been developed, providing concurrent operation at multiple frequency bands. The design of compact wideband baluns has been proposed as an extension of this theory. As proof-of-concept devices, both singleband and wideband baluns have been fabricated on Liquid Crystalline Polymer (LCP) based organic substrates. A novel passive-Q based optimization methodology has been developed for chip-package co-design of CMOS Low Noise Amplifiers (LNA). To implement these LNAs in a mixed-signal environment, a novel Electromagnetic Band Gap (EBG) based isolation scheme has also been employed.
The key contributions of this work are thus the development of novel RF circuit topologies utilizing embedded passives, and an advancement in the understanding and suppression of signal coupling mechanisms in mixed-signal SOP-based systems. The former will result in compact and highly integrated solutions for RF front-ends, while the latter is expected to have a significant impact in the integration of these communication devices with high performance computing.
14
Haghpanahan, Roohollah. "Metamaterials and their applications on antenna gain enhancement." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/12869.
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This thesis is devoted to potential applications of metamaterials in antenna structures as well as metamaterials behaviour, characterisation, structure design, simulation and extraction of parameters. The focus of this work is on the practical application of metamaterial structures for antenna performance enhancement. This thesis comprises three key parts; In the first part, theory of metamaterials is investigated including fields, polarisation, effective and average parameters, parameters extraction and transmission line (TL) model. In part two, zero index metamaterials (ZIM) theory is studied. The use of ZIM to form a highly directive medium is illustrated. A comparative study between different ZIM structures is conducted with a special attention to their operational bandwidth. ANSYS HFSS is used to model ZIM structures where simulation results show a bandwidth between 7.4% and 14.0%. Then two novel ZIM structures with a bandwidth of up to 33% are proposed. The first proposed ZIM is used to form a highly directive shell. Four directive shells are designed and placed around the dipole antenna where a gain increase of up to 6.8 dBi is obtained along the desired direction. Further, proposed ZIM cells are integrated with a quasi-Yagi antenna in order to increase its gain. Simulation results demonstrate gain enhancement for frequencies over which the proposed structure expresses ZIM properties. In part three, a new technique is stablished to design a metamaterial lens. The new technique is based on wave interference phenomena where engineered wave interference results in a desired spatial energy distribution. It is shown theoretically that having 180° phase difference between interfering waves results in a focused emission. Both hypothetical and metamaterial realisation models of a 180° phase shifter for a patch antenna are designed and simulated where a gain enhancement of 8 dBi and 5.77 dBi are achieved, respectively. Further, the concept of intended phase shift between interfering waves is used to design a novel bi-reflectional ground plane which can focus the reflected emission and consequently, increase the antenna directivity. In the theoretical model, the Perfect-E and Perfect-H planes are combined to form a bi-reflectional plane, whereas the practical model is designed using the copper cladding for the Perfect-E plane and the mushroom structure for the perfect-H plane. Both square and hexagonal geometries are used to form the mushroom structure. Simulation results confirm a gain enhancement of 5.4 dBi for the design using the square mushroom structure and a gain enhancement of 3.3 dBi for the design using the hexagonal mushroom structure.
15
Šedý, Michal. "Syntéza struktur s elektromagnetickým zádržným pásmem." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218036.
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In microwave frequency band, the planar technology is mainly used to fabricate electronic circuits. Propagation of surface waves belongs to the significant problem of this technology. Surface waves can cause unwanted coupling among particular parts of the structure and can degrade its parameters. The problem can be solved using an electromagnetic band gap structure (EBG). These periodic structures are able to suppress surface waves in different frequency bands. This thesis is focused on the modeling of these structures in the program COMSOL Multiphysics.
16
Zeng, Jingkun. "Compact Electromagnetic Band-Gap Structures (EBG) and Its Applications in Antenna Systems." Thesis, 2013. http://hdl.handle.net/10012/7374.
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This dissertation is focused on design of compact electromagnetic magnetic band-gap structures (EBG). Several popular compact techniques are introduced and analyzed with equivalent surface impedance model. A novel compact EBG structure is investigated. Compared to the conventional uniplanar compact photonic band gap (UC-PBG) structure, a size reduction of 64.7% is achieved. A distinctive band gap is observed at 2.45 GHz with around 100 MHz bandwidth and zero reflection phase. Antenna applications of this novel EBG structure, including EBG patch antenna and EBG antenna array, have been presented. Simulation results further verify its characteristic of suppressing surface waves. For the EBG patch antenna, a more focused radiation pattern is obtained compared to a normal patch antenna. For an antenna array, the presence of EBG structure reduces the mutual coupling between the two radiating elements by 6 dB.
17
Wong, Michael. "Dielectric Waveguides for Electromagnetic Band Gap (EBG) Structures, Antennas, and Microwave Circuits." Thesis, 2010. http://spectrum.library.concordia.ca/6604/1/Wong_PhD_S2010.pdf.
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Dielectric waveguide structures, formed using rectangular blocks of dielectric, can guide electromagnetic energy in a frequency range suitable for new microwave antennas and devices, or between 2 GHz and 18 GHz. In this thesis, we present the analysis and design of thin dielectric waveguide structures so small that for the first time, they can be made economically out of readily available substrates, or circuit boards, even at these frequencies. These strikingly thin metallic-bound dielectric waveguides (H-guides), to be operated in a single fundamental mode, are analyzed and subsequently applied to three brand new applications: a square periodic H-guide structure, an antenna, and a thin H-guide dual-directional coupler.
In the first application, we investigate periodic dielectric structures, or Electromagnetic Band Gap (EBG) structures, where a new model for periodicity applies thin H-guide transmission lines with discontinuities. This model allows for the resonant frequency, transmission (S21), and reflection (S11) parameters of such structures to be found quickly and quite accurately with closed form expressions, without the need for any numerical methods. As an added benefit of the new model, which can be represented as a z-transform, an inverse operation exists, creating the possibility to design a structure that meets a certain frequency response.
In the second application, we explore the use of the thin H-guide as a transmission line feed for a new type of aperture horn antenna that is not only high gain, but also wideband. Incredibly, with proper design, the antenna can also meet low-sidelobe levels between frequencies of 8 and 18 GHz. The proposed thin H-guide aperture horn antennas have wider bandwidths than typical array designs, have similarly high gains as compared to traditional air-filled horn antennas, and can even be easily fabricated using typical two dimensional substrate machining processes. The prototype operates from 8 to 18 GHz with a peak gain of about 18 dBi with reference to the H-guide transmission line.
To make antenna fabrication and measurement of periodic dielectric structures possible, a new transition based on microstrip design has been carefully developed that exceeds the performance of all previous microstrip to dielectric waveguide transition designs. This wideband, low loss, Bézier-shaped microstrip to thin H-guide transition has been carefully developed and is discussed in detail in this thesis. This transition can even be fabricated using the same two dimensional substrate machining processes used for the H-guide aperture horn antenna, which allows for the seamless integration of the two structures.
Finally, a dual-directional H-guide coupler is discussed that is much thinner than air-filled waveguide designs. The structure is so thin that its total thickness can be less than 2 millimeters, where the design obtains a directivity of better than 25 dB over a large bandwidth of 8 to 14 GHz.
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Chang, Sin-Min, and 張信珉. "A New Broadband Electromagnetic Band-gap (EBG) PowerPlanes with High Suppression of Ground Bounce Noise." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/86812155044209299481.
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碩士國立中山大學
電機工程學系研究所
92
In This Thesis , We primarily introduce some results with suppression of ground bounce noise in high-speed PCB by the formal researchers and summarize their advantages and weaknesses .In the next section .we explain why the EBG (Electromagnetic Band Gap ) design structure is from PBG (Photonic Band Gap ) concept in optical research field and that its principle can suppress GBN . We also summarize their advantages and weaknesses .In the following part, we define five parameters of EBG design structure to find the optimal solution by HFSS simulation method .The optimal solution can enlarge the bandwidth of suppression of GBN to 5.40GHz.We prove the accuracy of HFSS simulation method by actual measurement . When the EBG basic cell gradually compact from n=9.their characteristics are according to 1.central frequency towards high frequency 2.bandwidth of suppression of GBN is more broadband 3. forbiddance band depth becomes wider. Finally we oppose some new EBG design structures to solve some problems of old EBG design structure .These new EBG design structures can enhance signal integrity (SI) and law frequency response. Include three items 1.Meander design structure 2. Buddha design structure 3. Budder design structure .We also prove the accuracy of HFSS simulation method by actual measurement.
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Lin, Pao-Chun, and 林保君. "An Improved Electromagnetic Band-gap Structure with Applications." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/48224545672247511475.
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碩士元智大學
通訊工程學系
95
This thesis presents an improved electromagnetic band-gap structure which has the ability of reducing the RF circuitry sizes in low loss conditions due to the larger slow wave factor and broad band-gap characteristics. Several parameter tunings on the structure dimensions for improving the energy band-gap and the slow wave factor are discussed in detail in the thesis. In the application aspects, the miniature ring hybrid is demonstrated at the first, and then the microstrip bandpass filter with wide spurious suppression for WiMAX systems using the proposed structure is examined. Finally, the basic concept utilizing the electromagnetic band-gap structure on the output matching in active devices is addressed for enhancing circuit linearities and 1 dB compression point.
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Sudha, T. "Microstrip Antennas On Electromagnetic Band Gap Substrates For Mobile Applications." Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1412.
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Shen, Jian-Fu, and 沈建甫. "Analysis of Embedded Electromagnetic Band Gap (EEBG) Structures for Simultaneous Switching Noise Suppression in PCBs." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/98924237863247100944.
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碩士國立臺灣海洋大學
電機工程學系
98
In this thesis, we analyze various equivalent circuit models of EEBG (Embedded Electromagnetic Band-Gap) structure, and modify these equivalent circuits so that they become simpler without losing their accuracy. We further investigate DS-EEBG (Double-Stacked Embedded Electromagnetic Band-Gap) structures, analyze various configurations of DS-EEBG, and propose better configurations which have broader stopband, and better noise suppression performance. If reasonable equivalent circuit models are available, they can not only accurately estimate circuit parameters, but also save substantial simulation time compared to full-wave electromagnetic simulators. Therefore, we establish equivalent circuit models of DS-EEBG structure, and validate these equivalent circuits by comparing the results thus obtained with those calculated by the CST MWS, a FDTD-based commercial simulator. Situations of different patch width, substrate or via height are investigated and all the results compare favorably with those simulated by CST MWS. With these proposed equivalent circuits, rather accurate frequency range for the stopband can be predicted within several seconds of simulation time.
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HUANG, MENG-HSIANG, and 黃盟翔. "Design of Electromagnetic Band-gap Structure and Its Applications at Microwave Frequencies." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/58083592183057508208.
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碩士逢甲大學
通訊工程所
97
A novel electromagnetic band-gap structure is proposed in this study. The proposed EBG structure is designed and developed to provide two stop bands at 2.8GHz - 3.2GHz and 4.3GHz - 4.8 GHz on a standard FR4 substrate. By properly designing the unit cell dimension and arranging its location, the pronounced surface waves can be suppressed. Also, the mutual coupling can be reduced when the EBG are applied to electromagnetic compatibility. Besides, we used the proposed EBG structure to design superstrates. A 2×2 EBG array and a 4×4 EBG array had been separately fabricated to compose the superstrates. The EBG superstrates were combined with a patch antenna and a monopole antenna, respectively. The distance between antenna and superstrate is one half of wavelength at antenna’s operating frequency. Moreover, the effects on antenna gain and directivity under one and two layers of superstrate were investigated. The experimental results show that the antenna gain is improved obviously when the superstrate are with two-layer EBG structures. The antenna gain has a 2.5dB ~ 4dB increase at operating frequency. The gain performance has a remarkable promotion.
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Shu, Yao-Te, and 舒耀德. "Investigating Embedded Planar Electromagnetic Band Gap (EPEBG) Structure for Noise Suppression in PCBs." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/81873761884756265712.
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碩士國立臺灣海洋大學
電機工程學系
100
In this thesis, first we discuss the planar electromagnetic band gap (EBG) structures and its principles of noise suppression. The formulas of estimating the lower and higher frequencies of the suppression bandwidth are introduced. We observe that the planar EBG with hybrid placements of the metal bridge can achieve the widest noise suppression bandwidth. Then the embedded planar EBG structure are studied including noise suppression bandwidth estimating formulas, the number of shorting vias, and their location to effect noise suppression. Finally, we propose the equivalent circuit models for the embedded planar EBG structures. The simulation results of the equivalent circuits are compared favorably with those by a full wave solver, CST Microwave Studio, a FIT (Finite Integration Technique) - based method. Cases of different EBG dimensions, dielectric constant, bridges between patches, and locations of excitation and observations are studied. Both equivalent circuit and full wave results are very similar. Most simulations of the equivalent circuits can be completed in less than a minute. On the other hand, simulations by CST usually take more than one hour.
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Chang, Kai-Lin, and 張鎧麟. "A Novel Embedded Via Planar Electromagnetic Band Gap Structure for Noise Suppression PCBs." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/18887393093454333470.
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碩士國立臺灣海洋大學
電機工程學系
102
In this paper we propose a novel planner of electromagnetic band gap (EBG) structure, in which a spiral structure is designed to increase the inductance and thus of the noise suppression band can be lowered. We study different spiral structures to show how they affect the noise suppression bandwidth. By adjusting the section size in spirals, we attain an EBG which is characteristic of two noise suppression bands：0.45GHz~2.5GHz and 6.5~13.5GHz. To improve the noise suppression performance from 2.6GHz to 6.4GHz, several via holes are embedded in one spiral line and the resulting EBG yields a very wide noise suppression band. Furthermore, we try simplifying the spiral structure by reducing the number of sections from 6 to 4, and removing some metal area within the spiral. Thus new design can achieve a 310MHz~15GHz noise suppression frequency band.
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Raza, Shahzad. "Characterization of the Reflection and Dispersion Properties of 'Mushroom'-related Structures and their Applications to Antennas." Thesis, 2012. http://hdl.handle.net/1807/32618.
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The conventional mushroom-like Sievenpiper structure is re-visited in this thesis and a
relationship is established between the dispersion and reflection phase characteristics of the structure. It is shown that the reflection phase frequency at which the structure behaves as a Perfect Magnetic Conductor (PMC) can be predicted for varying angles of incidence from the modal distribution in the dispersion diagrams and corresponds to the supported leaky modes within the light cone. A methodology to independently tune the location of the PMC frequency point with respect to the surface wave band-gap location is then presented. The influence of having said PMC frequency point located inside or outside the surface wave band-gap on a dipole radiation pattern is then studied numerically. It is demonstrated that the antenna exhibits a higher gain when the PMC frequency and band-gap coincide versus when they are separated. Two design cases are then presented for when the aforementioned properties coincide and are separated and a gain improvement of 1.2 dB is measured for the former case.
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WANG, TSE-HSUAN, and 王策玄. "Using Modified Node Analysis and Segmentation Method to Calculate Arbitrarily Shaped Cavity Resonances Printed Circuit Board Power-Bus and Electromagnetic Band-Gap Structure." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/mq3h93.
Full textAbstract:
博士國立臺北科技大學
電子工程系
107
In the dissertation, the Modified Nodal Analysis (MNA) method, the segmentation method and the driving point impedance method are combined to replace segmentation method which calculated with the traditional manual deduction in order to compute the arbitrarily shaped cavity-mode. In the previous literature reviews, there were inaccurate problems about calculation result of double summation and discrete capacitors. In this study, the mathematical model and experiment have proved that the proposed method is more accurate than traditional methods. After mathematic deriving and practical measurements, the proposed method can solve efficiently proposed questions. At the same time, the simulation result is similar to experimental result. The deducted equations are conceptualized in matrices which can be easily programmable. The program can be executed with multiple processors that can greatly reduce computing time. The proposed method can facilitate calculations of arbitrarily shaped cavity, multi-layered circuit printed boards and discrete components combination. That is to say, we can save a lot of simulation execution time by using the proposed method than the traditional electromagnetic simulations software. Finally, we provide authentic examples to verify the accuracy of the proposed method.
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"Analysis, Design, Simulation, and Measurements of Flexible High Impedance Surfaces." Doctoral diss., 2013. http://hdl.handle.net/2286/R.I.20848.
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abstract: High Impedance Surfaces (HISs), which have been investigated extensively, have proven to be very efficient ground planes for low profile antenna applications due to their unique reflection phase characteristics. Another emerging research field among the microwave and antenna technologies is the design of flexible antennas and microwave circuits to be utilized in conformal applications. The combination of those two research topics gives birth to a third one, namely the design of Conformal or Flexible HISs (FHISs), which is the main subject of this dissertation. The problems associated with the FHISs are twofold: characterization and physical realization. The characterization involves the analysis of scattering properties of FHISs in the presence of plane wave and localized sources. For this purpose, an approximate analytical method is developed to characterize the reflection properties of a cylindrically curved FHIS. The effects of curvature on the reflection phase of the curved FHISs are examined. Furthermore, the effects of different types of currents, specifically the ones inherent to finite sized periodic structures, on the reflection phase characteristics are observed. After the reflection phase characterization of curved HISs, the performance of dipole antennas located in close proximity to a curved HIS are investigated, and the results are compared with the flat case. Different types of resonances that may occur for such a low-profile antenna application are discussed. The effects of curvature on the radiation performance of antennas are examined. Commercially available flexible materials are relatively thin which degrades the bandwidth of HISs. Another practical aspect, which is related to the substrate thickness, is the compactness of the surface. Because of the design limitations of conventional HISs, it is not possible to miniaturize the HIS and increase the bandwidth, simultaneously. To overcome this drawback, a novel HIS is proposed with a periodically perforated ground plane. Copper plated through holes are extremely vulnerable to bending and should be avoided at the bending parts of flexible circuits. Fortunately, if designed properly, the perforations on the ground plane may result in suppression of surface waves. Hence, metallic posts can be eliminated without hindering the surface wave suppression properties of HISs.Dissertation/Thesis
Ph.D. Electrical Engineering 2013