Electromagnetics and Photonics Commons^™

Coupling Path Visualization Based On Reciprocity Theorem, Yang Zhong

Masters Theses

"A new method to visualize coupling path is proposed to help solve EMI problems. Based on the reciprocity theorem and the concept of reaction, coupling coefficient (CC) is defined to characterize coupling power density. For two-port networks, surface integral of CC can represent coupled voltage on the open-circuited port or coupled power on the loaded port. For dipole-moment based systems, surface integral of CC can represent coupled field components. The calculated CC should be a complex scalar at each point. By properly adjusting the excitation phases, the imaginary part of surface integral of CC will be zero and thus can …

Practical Methods For Source Separation In Emc Measurements, Yuanzhuo Liu

Masters Theses

"Electromagnetic emission is critical in the electronic industry with the rapid growth of the development of the electronic device. To identify the emission from the multipule sources, two methods are proposed in the near field scan and total radiated power measurement respectively.

The first method can be applied in the measurement of the field generated by multiple non-correlated sources. The contribution of each source is determined using a blind source separation (BSS) technique. The measurements are performed using one scanning probe and stationary reference probes, avoiding the need to measure the spatial correlations of the random field. The resolving result …

Near-Field Scanning Based Shielding Effectiveness Extraction For Board Level Shielding Cans, Harsh Shrivastav

Masters Theses

"The conventional definition of shielding effectiveness is well suited for calculating electromagnetic shielding in the far-field. However, in the near field, shielding effectiveness calculation is not so straight forward. In radio frequency interference problems, most of the field coupling occurs in near field. Having a well-defined method to calculate near-field shielding effectiveness is important for estimating the suppression of radio frequency interference using the shield cans. In this research, a method to extract the shielding effectiveness of board level shielding cans using near field scanning is developed. Shielding effectiveness is defined by modelling the shielded noise source as equivalent dipole …

Experimental Characterization Of Common-Mode Sources For Prediction Of System Level Common-Mode Current On Cable Harnesses, Sameer Sudha Arun Walunj

Masters Theses

"Common-mode current on cable harnesses is often the primary source of radiated emissions below several hundred megahertz. It is difficult, however, to estimate common-mode currents that will occur in a system from component level tests because the common-mode impedances are different in the system. Research presents two methods for using simple component level tests to estimate equivalent common-mode source voltages and source impedances responsible for generating common-mode current. Key to these methods is assuming the harness can be represented with two transmission lines, one terminated with a short and one with an open. Equivalent sources are predicted for those circuits …

Estimating Electromagnetic Emissions From A Site Installation With Multiple Racks Of Server Equipment, Ze Sun

Masters Theses

“There are hundreds, sometimes even thousands, of servers working simultaneously inside a data center. Their radiation can be a problem and cause EMI issues. However, it is not feasible to perform full-wave simulation of these racks because of the large electric size of the model. In this thesis, an algorithm is proposed to predict the emission form rack array. The equivalent dipole source is extracted from EMI measurement data of a single rack and used as the radiation source in the multiple rack model. The coupling between racks cannot be ignored, but through the simulation, it is also found that …

Characterization And Modeling Of Esd Events And Near-Field Scanning Calibration Structures, Shubhankar Kashinath Marathe

Doctoral Dissertations

"This research is divided into three papers that cover, two major topics. The first topic, system-level electrostatic discharge (ESD), is discussed over the course of two papers. The second topic, a calibration structure for near-field scanning probe calibration application, is discussed in the last paper. In the first paper, software-assisted detection methods are proposed for secondary ESD discharges. The measured waveforms are analyzed with respect to waveform parameters, such as the vertical threshold of the rising edge, the derivative of the current waveform, and total charge delivered. These parameters enable automatic detection of secondary ESD while monitoring the discharge waveform …

Modeling Strategies For Estimating And Suppressing Electromagnetic Interference And Improving Power Integrity, Tamar Makharashvili

Doctoral Dissertations

"Decoupling capacitors are used to suppress high-frequency noise in power distribution networks. The inductance associated with a mounted decoupling capacitor can vary by 26% depending on characteristics of the printed circuit board. Here, simple and accurate inductance models of 2- and 8-terminal capacitors including connections to the power and return plane are developed. Circuit models of the capacitors and layout are created using the partial equivalent element circuit method which provide options for circuit-level simulations as well as analytic estimation of inductance. The circuit solution matches results from the full-wave simulation model within 9% for the 8-terminal capacitor and within …

Developing A Methodology For Estimating The Growth Of Radiated Emission From Multi-Modular Systems, Kaustav Ghosh

Masters Theses

"The large multiscale problems are commonly faced in real-world applications such as analysis of electromagnetic interference for a printed circuit board installed on a large platform with connected cables, wires and other high speed interfaces. EMI problems are not uncommon in high speed systems which involve multiple modules of complex hardware. As the system clock frequency and data rate increases, so does the challenges in controlling the EMI in such systems. The costs to prototype and to develop networking equipment are growing as a result of increasing complexities and densities. EMC regulations require radiated emission testing to be done in …

Development Of Hollow Coaxial Cable Fabry Perot Resonator For High Temperature Sensing Applications, Mohammed Farhan Ahmed

Masters Theses

"The thesis is comprised of two papers, the first paper presents the novel High-Quality Factor Coaxial Cable Fabry-Perot Resonator for sensing applications. The sensor is fabricated by creating two highly reflective mirrors in a coaxial cable. The temperature response of the sensor was tested, by monitoring the frequency shift of the reflection spectra as the temperature increased linearly from 35 °C to 80 °C in steps of 5 °C. The sensor exhibited high temperature sensitivity and good measurement resolution.

A high Q factor of 133 was recorded. The second paper in the thesis presents a low cost, robust, homemade hollow …

Tvs Transient Behavior Modeling Method, And System-Level Effective Esd Design For Usb3.X Interface, Pengyu Wei

Masters Theses

"This research proposal presents a methodology whereby a protection device can be modeled in SPICE compatible platforms with respect to the transient behaviors during Electrostatic Discharge (ESD) events. This methodology uses an exclusively "black-box" approach to characterize the parameters of the protection device, thereby allowing it to be implemented without intimate knowledge of the DUT. Results of this methodology can be used to predict the transient response (conductivity modulation and snapback delay) of the ESD protection devices, and thereby predicts how much current could flow into the device (typically a digital IO pin) under protection. The transient behavior modeling methodology …

Generating Fast And Accurate Compliance Reports For Various Data Rates, Srinath Penugonda

Masters Theses

"As the demands on the industry data rates have increased there is a need for interoperable interfaces to function flawlessly. Added to this complexity, the number of I/O data lines are also increasing making it more time consuming to design and test. This in general leads to creating of compliance standards to which interfaces must adhere. The goal of this theses is to aid the Signal Integrity Engineers with a better and fast way of rendering a full picture of the interface compliance parameters.

Three different interfaces at various data rates were chosen. They are: 25Gbps Very Short Reach (VSR) …

A Physics-Based Approach For Power Integrity In Multi-Layered Pcbs, Biyao Zhao

Masters Theses

"Developing a power distribution network (PDN) for ASICs and ICs to achieve the low-voltage ripple specifications for current digital designs is challenging with the high-speed and low-voltage ICs. Present methods are typically guided by best engineering practices for low impedance looking into the PDN from the IC. A pre-layout design methodology for power integrity in multi-layered PCB PDN geometry is proposed in the thesis. The PCB PDN geometry is segmented into four parts and every part is modelled using different methods based on the geometry details of the part. Physics-based circuit models are built for every part and the four …

Smart Rocks For Bridge Scour Monitoring -- Design And Localization Using Electromagnetic Techniques And Embedded Orientation Sensors, Andro Radchenko

Doctoral Dissertations

"River bridge scour is an erosion process in which flowing water removes sediment materials (such as sand, rocks) from a bridge foundation, river beds and banks. As a result, the level of the river bed near a bridge pier is lowering such that the bridge foundation stability can be compromised, and the bridge can collapse. The scour is a dynamic process, which can accelerate rapidly during a flood event. Thus, regular monitoring of the scour progress is necessary to be performed at most river bridges. Present techniques are usually expensive, require large man/hour efforts, and often lack the real-time monitoring …

Development Of Active Microwave Thermography For Structural Health Monitoring, Ali Foudazi

Doctoral Dissertations

"Active Microwave Thermography (AMT) is an integrated nondestructive testing and evaluation (NDT&E) method that incorporates aspects of microwave NDT and thermography techniques. AMT uses a microwave excitation to generate heat and the surface thermal profile of the material or structure under test is subsequently measured using a thermal camera (or IR camera). Utilizing a microwave heat excitation provides advantages over traditional thermal excitations (heat lamps, etc.) including the potential for non-contact, selective and focused heating. During an AMT inspection, two heating mechanisms are possible, referred to as dielectric and induction heating. Dielectric heating occurs as a result of the interaction …

Modal Based Bga Modeling In High-Speed Package, Shuai Jin

Doctoral Dissertations

"In the Section 1, the improved "Root-Omega" method for extracting dielectric properties from fabricated multilayer printed circuit boards is proposed. Based on the electrical properties of fabricated transmission lines, the improved "Root-Omega" method applied to cases with smooth and rough conductors is validated using simulations. Error sensitivity analysis is performed to demonstrate the potential errors in the original "Root-Omega" procedure and the error sensitivity is significantly reduced by the proposed improvements.

In the Section 2, a fast modal-based approach is developed to accurately and efficiently capture the proximity effect. Image theory is also applied in the proposed approach to reduce …

Improving Kinematic Accuracy Of Soft Wearable Data Gloves By Optimizing Sensor Locations, Donghyun Kim, Sang Wook Lee, Hyung-Soon Park

Electrical and Computer Engineering Faculty Research & Creative Works

Bending sensors enable compact, wearable designs when used for measuring hand configurations in data gloves. While existing data gloves can accurately measure angular displacement of the finger and distal thumb joints, accurate measurement of thumb carpometacarpal (CMC) joint movements remains challenging due to crosstalk between the multi-sensor outputs required to measure the degrees of freedom (DOF). To properly measure CMC-joint configurations, sensor locations that minimize sensor crosstalk must be identified. This paper presents a novel approach to identifying optimal sensor locations. Three-dimensional hand surface data from ten subjects was collected in multiple thumb postures with varied CMC-joint flexion and abduction …

Application Of Embedded Frequency Selective Surfaces For Structural Health Monitoring, Dustin Franklin Pieper

Masters Theses

"This thesis proposes the use of Frequency Selective Surfaces (FSSs) as an embedded structural health monitoring (SHM) sensor. FSSs are periodic arrays of conductive elements that filter certain frequencies of incident electromagnetic radiation. The behavior of this filter is heavily dependent on the geometry of the FSS and local environment. Therefore, by monitoring how this filtering response changes when the geometric or environmental changes take place, information about those changes may be determined. In previous works, FSS-based sensing has shown promise for sensing normal strain (a stretching or compressing geometrical deformation). This concept is extended in this thesis by investigating …

Esd Related Soft Error Detection And Root Cause Analysis, Suyu Yang

Masters Theses

"In this article, several methods are outlined for detecting functional changes in an IC due to external interference such as ESD or EMI. The goal is to provide diagnostic tools for detection of potential soft failure susceptibilities of complex systems during the hardware design stage without the aid of any complex software. After the soft errors are found, circuit modeling techniques are used to characterize the DUT. By running the circuit model, the soft error threshold can be predicted and the circuit model can be used to evaluate the performance of other ESD protection methods. In the end several methods …

Study Jitter Amplification Of A Passive Channel And Investigation Of S₂₁ Magnitude Extraction Methodologies Using A Pattern Generator And Oscilloscope, Xinyun Guo

Masters Theses

"Recently the clock channel jitter amplification has been observed in several publications. Currently in many high-speed I/O systems, to avoid the cost and the complex clock recovery circuit design, people use traces forwarding clock signal from transmitting IC to receiving IC. When these clock traces are long enough, the amount of attenuation will induce not only inter-symbol-interference (ISI) but also modulate with the input jitter. Eventually it will lead some type of jitter been amplified after the channel. Similarly, the high speed communication channel (data channel) will also face this issue. Since there are no studies on the jitter amplification …

Intensity Control Of Dielectric Barrier Discharge Filaments, Matthew Crawford Paliwoda

Masters Theses

"When operated in a filamentary mode, a volume dielectric barrier discharge (DBD) is known to produce patterned plasma structures. These structures are currently being explored for reconfigurable metamaterial applications. In this work the presence and intensity of a single filament, within an array of filaments, was controlled by adjusting the voltage to that filament's individual needle electrode. The current, voltage, and time-averaged normalized light intensity were measured while varying the voltage of the needle through a self-biasing resistance. For a 7.5 kV, 3.2 kHz DBD in air, the needle-controlled filament intensity varies from that of the surrounding filaments to zero …

Mitigation Of Glass Weave Skew Using A Combination Of Low Dk Spread Glass, Multi-Ply Dielectric And Routing Direction, Kartheek Nalla

Masters Theses

"As the data rates increase into the multi-gigabit range, the bit periods fall in the range of few tens of picoseconds. At above few Gbps, it becomes very important to reduce skew between differential pairs as it can adversely impact the signal eye and thereby increase bit error rate. The goal of this study is to mitigate the skew contributed by woven glass fabric of PCB dielectrics.

The glass weave skew between differential pairs in a PCB occurs due to the difference in dielectric constants (DK) of glass and resin. This thesis aims to mitigate the skew by reducing the …

Experimental Performance Evaluation And Design Of Schemes For Passive Rfid Network, Shadi Ebrahimi-Asl

Doctoral Dissertations

"Passive Radio Frequency Identification (RFID) is a short range technology for transferring information. The main advantage of passive RFID systems over active communication systems is the battery-less operation at the client sides. However, there are two major challenges that limit the widespread adaptation of passive RFID systems: short communication range and low read rate in dense deployments. This dissertation addresses these issues by studying the root causes and develops solutions for them.

In this dissertation, understanding the backscattering behavior of antennas and also the mutual coupling interactions among them are found to be the root causes of the two above-mentioned …

Emi Analysis Of Dvi Link Connectors, Abhishek Patnaik

Masters Theses

"EMI problems are not uncommon in high speed communication systems. As the system clock frequencies increases, so does the challenges in controlling the EMI in such systems. A connector is a very important part of a high speed communication system. Electromagnetic interference (EMI) is found to be tightly correlated to mode conversion: from differential-mode (DM) signals to common-mode (CM) currents and further to antenna-mode (AM) currents on the outside of cables or enclosures. Moreover, in such high speed systems, coupling to an adjacent cable-connector system is not uncommon. It is essential to understand and quantify this coupling path in order …

The Development Of Near Field Probing Systems For Emc Near Field Visualization And Emi Source Localization, Hui He

Masters Theses

"The objectives of this research are to visualize the frequency dependent electromagnetic field distribution for electromagnetic compatibility (EMC) applications and the radiating source reconstruction on complex shaped electronic systems. This is achieved by combining near field probing with a system for automatically recording the probe position and orientation. Due to the complexity of the shape of the electronic systems of interest, and for utilizing the expertise of the user, the probe will be moved manually not robotically. Concurrently, the local near field will be recorded, associated with the location and displayed at near real time on the captured 3D geometry …

An Improved Planar Cavity Model For Dielectric Characterization, Benjamin Jay Conley

Masters Theses

"Accurate characterization of the dielectric properties of the laminate materials used in printed circuit board fabrication is critical for maximizing the performance of modern high speed circuitry. While many techniques exist for characterizing dielectric materials, most existing techniques are either limited in accuracy or highly impractical for use with planar, copper-clad laminate sheets. A common method involves forming a cavity from the printed circuit board material and calculating the permittivity and dissipation factor from the measured resonant frequencies and quality factor of the cavity. This resonance technique makes the assumption of an ideal cavity, which leads to errors in both …

Emission Source Microscopy Applications On Emi Source Localization And Emi Mitigation With Lossy Materials, Xiangyang Jiao

Masters Theses

"In Section 1, the emission source microscopy (ESM) methodology will be introduced and used to identify the sources of radiation on different DUTs. As the new technology generation, the integration density and the operating speed of integrated circuits have been increasing steadily. However, root cause diagnostics to locate the source of EMI radiation is more problematic in the complex system. The ESM technique provides a powerful tool to detect and characterize the active sources of radiation. The amplitude and phase of fields are measured on a plane away from the DUT, and this measurement can get rid of the evanescent …

Electromagnetic Compatibility In Power Inverter Design, Natalia Bondarenko

Doctoral Dissertations

"Power inverter systems generate significant electromagnetic emissions. Methods were studied to model these systems and to reduce their emissions. Three topics are presented in this dissertation.

Methods were developed to obtain simple SPICE models for complex systems which relate circuit components to physical geometry within the system. These models were derived using measurements or using partial element equivalent circuit (PEEC) and model size reduction techniques developed in this dissertation. Methods were proposed for developing a measurement-based model and were applied to a real power inverter/motor system. The model was used to identify system geometries responsible for critical resonances and to …

Pulsed Inductive Plasma Studies By Spectroscopy And Internal Probe Methods, Warner C. Meeks

Doctoral Dissertations

The broad effort of the Missouri Plasmoid Experiment is to elucidate the energy conversion processes in a pulsed inductive discharge due to the presence of plasma. The test article is a 440 to 490 kHz theta-pinch (or solenoidal) geometry coil with a stored energy of around 80 joules. In this work experimental hydrogen, helium, argon and xenon data at back-fill pressures of 10 to 100 mTorr (1.3 to 133.3 Pa) are obtained and interpreted. Spectral and internal probe studies were performed on MPX Mk.I and Mk.II devices, respectively. IR spectra were acquired in the Mk.I device for argon and xenon. …

Near-Field Scanning Study For Radio Frequency Interference Estimation, Jingnan Pan

Doctoral Dissertations

"This dissertation discusses the novel techniques using near-fields scanning to do radio frequency interference (RFI) estimation. As the electronic products are becoming more and more complicated, the radio frequency (RF) receiver in the system is very likely interfered by multiple noise sources simultaneously. A method is proposed to identify the interference from different noise sources separately, even when they are radiating at the same time. This method is very helpful for engineers to identify the contribution of the coupling from different sources and further solve the electromagnetic interference issues efficiently. On the other hand, the equivalent dipole-moment models and a …

First Demonstration Of Ultra-Thin Sige-Channel Junctionless Accumulation-Mode (Jam) Bulk Finfets On Si Substrate With Pn Junction-Isolation Scheme, Donghyun Kim, Tae Kyun Kim, Young Gwang Yoon, Byeong Woon Hwang, Yang-Kyu Choi, Byung Jin Cho, Seok-Hee Lee

Electrical and Computer Engineering Faculty Research & Creative Works

A SiGe-channel junctionless-accumulation-mode (JAM) PMOS bulk FinFETs were successfully demonstrated on Si substrate with PN junction-isolation scheme for the first time. The JAM bulk FinFETs with fin width of 18 nm exhibits excellent subthreshold characteristics such as subthreshold swing of 64 mV/decade, drain-induced barrier lowering (DIBL) of 40 mV/V and high I_on/I_off current ratio ( > 1 x 10⁵). The change of substrate bias from 0 to 5 V leads to the threshold voltage shift of 53 mV by modulating the effective channel thickness. When compared to the Si-channel bulk FinFETs with fin width of 18 …