3,142 research outputs found

    UMSL Bulletin 2023-2024

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    The 2023-2024 Bulletin and Course Catalog for the University of Missouri St. Louis.https://irl.umsl.edu/bulletin/1088/thumbnail.jp

    UMSL Bulletin 2022-2023

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    The 2022-2023 Bulletin and Course Catalog for the University of Missouri St. Louis.https://irl.umsl.edu/bulletin/1087/thumbnail.jp

    Investigation into Photon Emissions as a Side-Channel Leakage in Two Microcontrollers: A Focus on SRAM Blocks

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    Microcontrollers are extensively utilized across a diverse range of applications. However, with the escalating usage of these devices, the risk to their security and the valuable data they process correspondingly intensifies. These devices could potentially be susceptible to various security threats, with side channel leakage standing out as a notable concern. Among the numerous types of side-channel leakages, photon emissions from active devices emerge as a potentially significant concern. These emissions, a characteristic of all semiconductor devices including microcontrollers, occur during their operation. Depending on the operating point and the internal state of the chip, these emissions can reflect the device’s internal operations. Therefore, a malicious individual could potentially exploit these emissions to gain insights into the computations being performed within the device. This dissertation delves into the investigation of photon emissions from the SRAM blocks of two distinct microcontrollers, utilizing a cost-effective setup. The aim is to extract information from these emissions, analyzing them as potential side-channel leakage points. In the first segment of the study, a PIC microcontroller variant is investigated. The quiescent photon emissions from the SRAM are examined. A correlation attack was successfully executed on these emissions, which led to the recovery of the AES encryption key. Furthermore, differential analysis was used to examine the location of SRAM bits. The combination of this information with the application of an image processing method, namely the Structural Similarity Index (SSIM), assisted in revealing the content of SRAM cells from photon emission images. The second segment of this study, for the first time, emphasizes on a RISC-V chip, examining the photon emissions of the SRAM during continuous reading. Probing the photon emissions from the row and column detectors led to the identification of a target word location, which is capable of revealing the AES key. Also, the content of target row was retrieved through the photon emissions originating from the drivers and the SRAM cells themselves. Additionally, the SSIM technique was utilized to determine the address of a targeted word in RISC-V photon emissions which cannot be analyzed through visual inspection. The insights gained from this research contribute to a deeper understanding of side-channel leakage via photon emissions and demonstrate its potential potency in extracting critical information from digital devices. Moreover, this information significantly contributes to the development of innovative security measures, an aspect becoming increasingly crucial in our progressively digitized world

    A New Front-End System For UAV-Based Antenna Measurements For Polarimetric Weather Radars

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    Radar system calibration is vital for ensuring optimal performance, especially in weather radars that have stringent requirements for co-polarization mismatch. In-field calibration is essential, particularly for mobile weather radars, as environmental conditions can vary between deployments. Traditionally, conventional far-field ranges or airborne systems such as helicopters and aircraft have been used to measure and calibrate radar systems. However, in recent years, Unmanned Aerial Systems (UAS) have emerged as a cost-effective and flexible alternative for antenna measurement and radar calibration. Previous studies have demonstrated the feasibility of using UAS for far-field antenna measurements across various operating frequencies. These works have achieved high accuracy in characterizing and calibrating polarimetric weather radar systems, meeting critical requirements such as co-polarization mismatch below 0.1 dB and cross-polarization isolation below -45 dB. However, existing UAS-based systems are complex to operate, requiring multiple equipment both on the UAS and the ground station. They are primarily limited to one-way transmission from the UAS to the AUT and lack the capability to switch between RX and TX measurements or H- and V-polarization without physical modifications. The objective of this thesis is to develop a lightweight and self-contained front-end system for UAS-based in-situ antenna characterization. This system will eliminate the need for additional RF instruments on the ground, providing remote real-time control to switch between RX and TX modes in both V- and H-polarization. It will also facilitate the transmission and reception of measurement data over long distances, enabling far-field measurements beyond 120 m. The proposed system aims to address the limitations of existing UAS-based calibration systems, offering a sophisticated and accurate solution for measuring the strictest radar systems. By developing a versatile and lightweight front-end system, this research seeks to advance the field of UAS-based antenna characterization and contribute to the improvement of radar calibration techniques

    Accurate quantum transport modelling and epitaxial structure design of high-speed and high-power In0.53Ga0.47As/AlAs double-barrier resonant tunnelling diodes for 300-GHz oscillator sources

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    Terahertz (THz) wave technology is envisioned as an appealing and conceivable solution in the context of several potential high-impact applications, including sixth generation (6G) and beyond consumer-oriented ultra-broadband multi-gigabit wireless data-links, as well as highresolution imaging, radar, and spectroscopy apparatuses employable in biomedicine, industrial processes, security/defence, and material science. Despite the technological challenges posed by the THz gap, recent scientific advancements suggest the practical viability of THz systems. However, the development of transmitters (Tx) and receivers (Rx) based on compact semiconductor devices operating at THz frequencies is urgently demanded to meet the performance requirements calling from emerging THz applications. Although several are the promising candidates, including high-speed III-V transistors and photo-diodes, resonant tunnelling diode (RTD) technology offers a compact and high performance option in many practical scenarios. However, the main weakness of the technology is currently represented by the low output power capability of RTD THz Tx, which is mainly caused by the underdeveloped and non-optimal device, as well as circuit, design implementation approaches. Indeed, indium phosphide (InP) RTD devices can nowadays deliver only up to around 1 mW of radio-frequency (RF) power at around 300 GHz. In the context of THz wireless data-links, this severely impacts the Tx performance, limiting communication distance and data transfer capabilities which, at the current time, are of the order of few tens of gigabit per second below around 1 m. However, recent research studies suggest that several milliwatt of output power are required to achieve bit-rate capabilities of several tens of gigabits per second and beyond, and to reach several metres of communication distance in common operating conditions. Currently, the shortterm target is set to 5−10 mW of output power at around 300 GHz carrier waves, which would allow bit-rates in excess of 100 Gb/s, as well as wireless communications well above 5 m distance, in first-stage short-range scenarios. In order to reach it, maximisation of the RTD highfrequency RF power capability is of utmost importance. Despite that, reliable epitaxial structure design approaches, as well as accurate physical-based numerical simulation tools, aimed at RF power maximisation in the 300 GHz-band are lacking at the current time. This work aims at proposing practical solutions to address the aforementioned issues. First, a physical-based simulation methodology was developed to accurately and reliably simulate the static current-voltage (IV ) characteristic of indium gallium arsenide/aluminium arsenide (In-GaAs/AlAs) double-barrier RTD devices. The approach relies on the non-equilibrium Green’s function (NEGF) formalism implemented in Silvaco Atlas technology computer-aided design (TCAD) simulation package, requires low computational budget, and allows to correctly model In0.53Ga0.47As/AlAs RTD devices, which are pseudomorphically-grown on lattice-matched to InP substrates, and are commonly employed in oscillators working at around 300 GHz. By selecting the appropriate physical models, and by retrieving the correct materials parameters, together with a suitable discretisation of the associated heterostructure spatial domain through finite-elements, it is shown, by comparing simulation data with experimental results, that the developed numerical approach can reliably compute several quantities of interest that characterise the DC IV curve negative differential resistance (NDR) region, including peak current, peak voltage, and voltage swing, all of which are key parameters in RTD oscillator design. The demonstrated simulation approach was then used to study the impact of epitaxial structure design parameters, including those characterising the double-barrier quantum well, as well as emitter and collector regions, on the electrical properties of the RTD device. In particular, a comprehensive simulation analysis was conducted, and the retrieved output trends discussed based on the heterostructure band diagram, transmission coefficient energy spectrum, charge distribution, and DC current-density voltage (JV) curve. General design guidelines aimed at enhancing the RTD device maximum RF power gain capability are then deduced and discussed. To validate the proposed epitaxial design approach, an In0.53Ga0.47As/AlAs double-barrier RTD epitaxial structure providing several milliwatt of RF power was designed by employing the developed simulation methodology, and experimentally-investigated through the microfabrication of RTD devices and subsequent high-frequency characterisation up to 110 GHz. The analysis, which included fabrication optimisation, reveals an expected RF power performance of up to around 5 mW and 10 mW at 300 GHz for 25 μm2 and 49 μm2-large RTD devices, respectively, which is up to five times higher compared to the current state-of-the-art. Finally, in order to prove the practical employability of the proposed RTDs in oscillator circuits realised employing low-cost photo-lithography, both coplanar waveguide and microstrip inductive stubs are designed through a full three-dimensional electromagnetic simulation analysis. In summary, this work makes and important contribution to the rapidly evolving field of THz RTD technology, and demonstrates the practical feasibility of 300-GHz high-power RTD devices realisation, which will underpin the future development of Tx systems capable of the power levels required in the forthcoming THz applications

    The design of a fully balanced current–tunable active RC integrator

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    The design of the active RC integrator presented in this research utilizes a fully balanced technique and current-tunable frequencies to create the active RC integrator and reliable circuit. The circuit is made up of six npn bipolar junction transistors (BJT), six resistors (R), and a capacitor (C), with the fully balanced technique used to make the circuit structure uncomplicated and symmetrical with signal differencing. This approach results in a low number of internal devices in the circuit, making it an attractive option for integrated circuit (IC) development. One of the key features of the fully balanced current-tunable active RC integrator is its ability to be frequency-tunable with bias current (If). This feature enables the circuit to be used in a variety of applications, including filter circuits, communication signal generators, instrumentation signal generators, and various automatic controls. The fully balanced design also ensures that the circuit is stable and robust, even in the presence of device parameter variations. To evaluate the performance of the active RC integrator, simulations were conducted using Pspice. The results show that a fully current-tunable active RC integrator can be precisely tuned with the active bias to a value consistent with the theoretically calculated value. This demonstrates the efficiency and reliability of the circuit design and simulation method. The Monte Carlo (MC) method was also used to analyze the circuit performance in cases where the resistor (R) and capacitor (C) device had a 10 percent error and the transistor gain (β) was set to an error of 50 percent. The MC analysis showed that the phase shift (degree) and magnitude (dB) of the circuit were stable, and the circuit's performance was not significantly impacted by the device parameter variations. This further demonstrates the robustness and versatility of the fully balanced current-tunable active RC integrator design. Finally, harmonic distortion was evaluated to confirm the performance of the designed and developed fully balanced current-tunable active RC integrator. The results showed low levels of harmonic distortion, which indicates that the circuit is suitable for high-performance applications that require low distortio

    A miniature tunable quadrature shadow oscillator with orthogonal control

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    This article presents a new design of a quadrature shadow oscillator. The oscillator is realized using one input and two outputs of a second-order filter cell together with external amplifiers in a feedback configuration. The oscillation characteristics are controlled via the external gain without disturbing the internal filter cell, following the concept of the shadow oscillator. The proposed circuit configuration is simple with a small component-count. It consists of, two voltage-different transconductance amplifiers (VDTAs) along with a couple of passive elements. The frequency of oscillation (FO) and the condition of oscillation (CO) are controlled orthogonally via the dc bias current and external gain. Moreover, with the addition of the external gain, the frequency range of oscillation can be further extended. The proposed work is verified by computer simulation with the use of 180 nm complementary metal–oxide–semiconductor (CMOS) model parameters. The simulation gives satisfactory results of two sinusoidal output signals in quadrature with some small total harmonic distortions (THD). In addition, a circuit experiment is performed using the commercial operational transconductance amplifiers LM13700 as the active components. The circuit experiment also demonstrates satisfactory outcome which confirms the validity of the proposed circuit

    Taylor University Catalog 2023-2024

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    The 2023-2024 academic catalog of Taylor University in Upland, Indiana.https://pillars.taylor.edu/catalogs/1128/thumbnail.jp

    Magnetic Integration Techniques for Resonant Converters

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    This thesis sets out a series of new transformer topologies for magnetic integration in different resonant converters. Resonant converters like LLC converters require a high number of magnetic components, leading to low power density and high cost. These magnetic components can usually be integrated into a single transformer to increase power density, efficiency, manufacturing simplicity and to reduce cost. This strategy is known as integrated transformer (IT). The work described in this thesis has sought to deliver improvements in implementing this strategy. The benefits of resonant converters compared to pulse-width-modulated (PWM) converters are discussed. To show the drawbacks of PWM converters, two hard-switched DC-DC converters and two soft-switched DC-DC converters using state-of-the-art wide bandgap (WBG) gallium nitride devices are constructed and investigated. The LLC resonant converter is fully discussed for unidirectional and bidirectional applications. The different techniques for magnetic integration that can be applied to the LLC resonant converter are reviewed. Amongst these techniques, the inserted-shunt integrated transformers, which have gained popularity recently, are made a focus of the thesis. In general, the important challenges concerning the inserted-shunt integrated transformers are the need for bespoke material for the shunt, unwanted high leakage inductance on the secondary side, and that integrated magnetics are not usually suitable for bidirectional converters such as CLLLC converters. Two new topologies (IT1 and IT2) for inserted-shunt integrated transformers are presented that do not need bespoke material for the shunt and can be constructed from materials available commercially in large and small quantities. However, the manufacturing of these proposed topologies is challenging since magnetic shunts are made by joining several smaller magnetic pieces to form a segmented piece. A further new topology (IT3) is presented that not only does not need bespoke material for the shunt but also benefits from simple manufacturing. However, inserted-shunt integrated transformer, including all three proposed topologies (IT1-IT3), still suffer from increased leakage inductance on the secondary side, leading the control and design of the resonant converters to difficulty. Another topology (IT4) is therefore proposed that can be constructed easily with commercially available materials and does not increase the leakage inductance on the secondary side. However, all four proposed topologies (IT1-IT4) and other topologies with an inserted-shunt are not suitable for use in bidirectional LLC-type resonant converters when different primary and secondary leakage inductances are needed, such as where variable gain is required. Finally, a topology (IT5) is proposed that can be used in bidirectional LLC-type converters while it still benefits from simple manufacturing and using commercially available materials. All the proposed topologies (IT1-IT5) are discussed in detail and their design guidelines and modelling are provided. The theoretical analysis is confirmed by finite-element (FEM) analysis and experimental results. A unidirectional LLC resonant converter and a bidirectional CLLLC resonant converter are implemented to investigate the performance of the proposed integrated transformers (IT1-IT5) in practice. It is shown that the converters can operate properly while all their magnetic components are integrated into the proposed transformers

    Integrated Optical Receivers for High-speed Indoor Optical Wireless Communication

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