Closed-Form Expression For The Net Ground Plane Inductance Of Coplanar Stripline Pcbs, 2015 E&SI, Caterpillar Inc., Peoria, IL
Closed-Form Expression For The Net Ground Plane Inductance Of Coplanar Stripline Pcbs, Li Huadong, Guru Subramanyam
Guru Subramanyam
The net ground plane inductance of printed circuit boards is the source of common-mode radiated emissions. Correct determination of the net ground plane inductance provides a quick estimation of the radiated emissions from printed circuit boards. Employing conformal mapping technique, this paper gives a closed-form expression for the per unit length net ground plane inductance of coplanar stripline printed circuit boards with finite ground plane width. Current density distribution on the ground plane is also obtained.
A Low Voltage Tunable Analog Phase Shifter Utilizing Ferroelectric Varactors, 2015 University of Dayton
A Low Voltage Tunable Analog Phase Shifter Utilizing Ferroelectric Varactors, Guru Subramanyam, Kevin Leedy, Chakrapani Varanasi, Robert Neidhard, Keith Stamper, Mark Calcatera
Guru Subramanyam
A distributed transmission line phase shifter was implemented by periodically loading a coplanar transmission line using ferroelectric varactors in a shunt configuration. A single dc bias applied to the phase shifter circuit provides a large relative phase shift. A relative phase shift of ∼ 305 degrees was obtained at 20 GHz for a dc bias of only 5 V.
Generalized Memristive Device Spice Model And Its Application In Circuit Design, 2015 University of Dayton
Generalized Memristive Device Spice Model And Its Application In Circuit Design, Chris Yakopcic, Tarek Taha, Guru Subramanyam, R. Pino
Guru Subramanyam
This paper presents a SPICE model for memristive devices. It builds on existing models and is correlated against several published device characterization data with an average error of 6.04%. When compared to existing alternatives, the proposed model can more accurately simulate a wide range of published memristors. The model is also tested in large circuits with up to 256 memristors, and was less likely to cause convergence errors when compared to other models. We show that the model can be used to study the impact of memristive device variation within a circuit. We examine the impact of nonuniformity in device …
Microwave Dielectric Properties Of Epitaxial Mn-Doped Ba(Zr,Ti)O-3 Thin Films On Laalo3 Substrates, 2015 Xi'an Jiaotong University
Microwave Dielectric Properties Of Epitaxial Mn-Doped Ba(Zr,Ti)O-3 Thin Films On Laalo3 Substrates, Ming Liu, Chunrui Ma, Jian Liu, Gregory Collins, Chonglin Chen, Andy Alemayehu, Guru Subramanyam, Chao Dai, Yuan Lin, Amar Bhalla
Guru Subramanyam
Environmental friendly ferroelectric relaxor Ba(Zr0.2Ti0.8)O3 thin films with an additional 2% Mn dopant were epitaxially fabricated on the (001) LaAlO3 single crystal substrates by pulsed laser deposition. Microstructure characterizations from x-ray diffraction suggest that the films are c-axis oriented with the interface relationship of [101]Mn:BZT//[100]LAO and (001)Mn:BZT //(001)LAO. The microwave dielectric property measurements (13–17.5 GHz) reveal that the films have excellent dielectric properties with large tunability, high dielectric constant, and low dielectric loss, which the average value is 25.9%, 169 and 0.054, respectively. It is indicated that the additional 2% Mn doped Ba(Zr0.2Ti0.8)O3 thin films can be used for the …
Influence Of Space-Charge On Hysteresis Loop Characteristics Of Ferroelectric Thin Films, 2015 University of Dayton
Influence Of Space-Charge On Hysteresis Loop Characteristics Of Ferroelectric Thin Films, Huadong Li, Guru Subramanyam, S. Dey
Guru Subramanyam
Hysteresis loops of Pb(Zr, Ti)O3 (PZT) thin films obtained by using a Sawyer-Tower (ST) circuit are affected by many factors. This paper investigated the influence of space charge on the hysteresis loop of thin-film ferroelectrics, based on the model that polarization consists of two parts: linear and switching polarization. It is found that the space charge affects both the shape and offset of the ideal hysteresis loop. Further investigation shows that the practical hysteresis loop has a close relationship with the equivalent ST circuit parameters: the leakage resistance of the FE film, the equivalent input impedance of the measurement equipment, …
Miniaturized And Reconfigurable Cpw Square Ring Slot Antenna Loaded With Bst Thin Film Varactors, 2015 University of Dayton
Miniaturized And Reconfigurable Cpw Square Ring Slot Antenna Loaded With Bst Thin Film Varactors, Hai Jiang, Mark Patterson, Dustin Brown, Chenhao Zhang, Kuanchang Pan, Guru Subramanyam, David Kuhl, Kevin Leedy, Charles Cerny
Guru Subramanyam
A novel miniaturized and reconfigurable coplanar waveguide (CPW) square-ring slot antenna is presented in this paper. The miniaturization is achieved via a hybrid approach including ferroelectric varactor loadings, high dielectric constant materials, and tuning stub for impedance matching. For the first time, nine shunt ferroelectric (FE) BST (Ba(1-x)SrxTiO3) thin film varactors are integrated with the CPW antenna structure achieving both antenna miniaturization and reconfiguration at the same time. The size of the miniaturized antenna is reduced to 0.067λ0 0.067λ0 without ground, and 0.1λ0 0.1λ0 with ground. The resonant frequency of the miniaturized antenna can be reconfigured from 5.3 GHz to …
Novel Multi-Capacitor Architecture For Bst Thin Film Varactors, 2015 University of Dayton
Novel Multi-Capacitor Architecture For Bst Thin Film Varactors, Guru Subramanyam, M. Patterson, K. Leedy, R. Neidhard, C. Varanasi, G. Steinhauer
Guru Subramanyam
Novel Barium Strontium Titanate (BST) thin film varactors with parallel capacitor architecture were designed fabricated and tested. Varactors with 2–6 parallel capacitors were experimentally verified using large area processed bst thin films. The multicapacitor varactor shunt switches provided improved isolation at the expense of higher insertion loss. The multicapacitor varactors yielded reduced overall parasitic series inductance and resistances, resulting in higher quality factor Q. This is the first time such a device is reported.
Performance Of Thin Film Ferroelectrics With Dopant-Ion Charges, 2015 University of Dayton
Performance Of Thin Film Ferroelectrics With Dopant-Ion Charges, Huadong Li, Guru Subramanyam, Jiadong Wang
Guru Subramanyam
This paper studied the effect of dopant-ion charges on the performance of thin film ferroelectrics. Field distributions and capacitance of ferroelectric thin films with different dopant-ion charge densities are analyzed. The non-linearity of the electric field inside the thin film increases with the dopant-ion charge density and decreases with the linear permittivity of the ferroelectric thin film. Once the applied voltage is strong enough, the field distribution will become linear. The FE thin film peak capacitance reduces with the dopant-ion charge density and the total area under the C-V curve between two large voltages with opposite signs is fixed.
Voltage Tunable Epitaxial Pb X Sr(1− X )Tio3 Films On Sapphire By Mocvd: Nanostructure And Microwave Properties, 2015 Arizona State University at the Tempe Campus
Voltage Tunable Epitaxial Pb X Sr(1− X )Tio3 Films On Sapphire By Mocvd: Nanostructure And Microwave Properties, S. Dey, C. Wang, W. Cao, S. Bhaskar, J. Li, Guru Subramanyam
Guru Subramanyam
Frequency and phase agile microwave components such as tunable filters and phase shifters will require ferroelectric thin films that exhibit a nonlinear dependence of dielectric permittivity (ɛ r ) with dc electric bias, as well as a high material (Δɛ r /tan δ) and device (or K-factor in phase shift/dB) figure of merits (FOM). Therefore, voltage tunable (Pb0.3Sr0.7)TiO3 (PST) thin films (90–150 nm) on (0001) sapphire were deposited by metal-organic chemical vapor deposition at rates of 10–15 nm/min. The as-deposited epitaxial PST films were characterized by Rutherford backscattering spectroscopy, X-ray methods, field …
Fabrication And Characterization Of Polycarbonate Polyurethane (Pcpu) Nanofibers Impregnated With Nanofillers, 2015 University of South Florida
Fabrication And Characterization Of Polycarbonate Polyurethane (Pcpu) Nanofibers Impregnated With Nanofillers, Hruday Chand Katakam
USF Tampa Graduate Theses and Dissertations
Polycarbonate polyurethane (PCPU) has been studied as a novel polymer impregnated with nanoparticles for improved mechanical, thermal and adhesion properties [4]. This study investigates the synthesis of polycarbonate polyurethane (PCPU) polymeric nanofiber membranes by the process of electrospinning. This study further examines all the parameters associated with electrospinning a novel PCPU polymeric solution impregnated with nanofillers, such as nanoparticles, to produce fiber membranes. Tetrahydrofuran (THF) and N, N dimethylformamide (DMF) are used as solvents to dissolve PCPU polymer. One percent (1%) of nanofillers like silver and silica nanoparticles are added to PCPU polymer solution to investigate the impact on polymer …
Challenges And Opportunities For Multi-Functional Oxide Thin Films For Voltage Tunable Radio-Frequency/Microwave Components, 2015 University of Dayton
Challenges And Opportunities For Multi-Functional Oxide Thin Films For Voltage Tunable Radio-Frequency/Microwave Components, Guru Subramanyam, M W. Cole, Nian X. Sun, Thottam S. Kalkur, Nick M. Sbrockey, Gary S. Tompa, Xiaomei Guo, Chonglin Chen, S P. Alpay, G A. Rossetti Jr., Kaushik Dayal, Long-Qing Chen, Darrell G. Schlom
Guru Subramanyam
There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated …
Trapping Light With Nanostructures For Sensors, 2015 University of Alabama in Huntsville
Trapping Light With Nanostructures For Sensors, Kareem Garriga
Summer Community of Scholars Posters (RCEU and HCR Combined Programs)
No abstract provided.
Coherent Spin Transport In Nanowire Spin Valves And Novel Spintronic Device Possibilities, 2015 Virginia Commonwealth University
Coherent Spin Transport In Nanowire Spin Valves And Novel Spintronic Device Possibilities, Md Iftekhar I. Hossain, Supriyo Bandyopadhyay, Jayasimha Atulasimha, Saumil Bandyopadhyay
Graduate Research Posters
We have proposed a spintronic infrared photodetector backed by experimental evidence and matched with theoretical prediction obtained in our labs. Unlike conventional photodetectors, it can work at room temperature with ideally infinite light-to-dark contrast ratio, infinite detectivity and zero dark current. The proposed idea is based on smart implementation of spin polarized transport. Electrons while travelling through one-dimensional channel show long spin relaxation length if they can be confined to a single conduction subband because of the elimination of major spin relaxation mechanism, namely the D’yakonov-Perel’ mechanism. With infrared light, electrons can be excited to higher subbands, resulting in the …
Strain Controlled Ultra-Low-Energy Magnetic Tunneling Junction, 2015 Virginia Commonwealth University
Strain Controlled Ultra-Low-Energy Magnetic Tunneling Junction, Hasnain Ahmad, Supriyo Bandyopadhyay, Jayasimha Atulasimha
Graduate Research Posters
We are experimenting on designing a voltage-controlled ultra-low-energy Magnetic Tunneling Junction (MTJ) device using a soft single domain magnetostrictive layer (i.e. Galfenol: Fe1-xGax , x = 20 At%) coupled to a piezoelectric layer (i.e. PMN-PT). Special metal pads have been designed using photolithography to generate stress in the PMN-PT layer by applying electric field. The patterns of different shape anisotropic nano-magnets are designed using e-beam lithography and we have successfully fabricate FeGa nanomagnets with only 12 to 13 nanometer thickness by sputter deposition. These nanomagnets have been characterized by magnetic force microscopy for observing their switching capabilities. …
Nanostructured Semiconductor Device Design In Solar Cells, 2015 University of Kentucky
Nanostructured Semiconductor Device Design In Solar Cells, Hongmei Dang
Theses and Dissertations--Electrical and Computer Engineering
We demonstrate the use of embedded CdS nanowires in improving spectral transmission loss and the low mechanical and electrical robustness of planar CdS window layer and thus enhancing the quantum efficiency and the reliability of the CdS-CdTe solar cells. CdS nanowire window layer enables light transmission gain at 300nm-550nm. A nearly ideal spectral response of quantum efficiency at a wide spectrum range provides an evidence for improving light transmission in the window layer and enhancing absorption and carrier generation in absorber. Nanowire CdS/CdTe solar cells with Cu/graphite/silver paste as back contacts, on SnO2/ITO-soda lime glass substrates, yield the …
Electron-Beam Patterning Of Teflon Af For Surface Plasmon Resonance Sensing, 2015 University of Kentucky
Electron-Beam Patterning Of Teflon Af For Surface Plasmon Resonance Sensing, Mansoor A. Sultan
Theses and Dissertations--Electrical and Computer Engineering
Variable pressure electron beam etching and lithography for Teflon AF has been demonstrated. The relation between dose and etching depth is tested under high vacuum and water vapor. High resolution structures as small as 75 nm half-pitch have been resolved. Several simulation tools were tested for surface plasmon excitation. Grating based dual mode surface plasmon excitation has been shown numerically and experimentally.
Multiferroic Tunnel Junctions And Ferroelectric Control Of Magnetic State At Interface, 2015 Pennsylvania State University
Multiferroic Tunnel Junctions And Ferroelectric Control Of Magnetic State At Interface, Y. W. Yin, M. Raju, W. J. Hu, John D. Burton, Y.-M. Kim, A. Y. Borisevich, S. J. Pennycook, S. M. Yang, T. W. Noh, Alexei Gruverman, X. G. Li, Z. D. Zhang, Evgeny Y. Tsymbal, Qi Li
Alexei Gruverman Publications
As semiconductor devices reach ever smaller dimensions, the challenge of power dissipation and quantum effect place a serious limit on the future device scaling. Recently, a multiferroic tunnel junction (MFTJ) with a ferroelectric barrier sandwiched between two ferromagnetic electrodes has drawn enormous interest due to its potential applications not only in multi-level data storage but also in electric field controlled spintronics and nanoferronics. Here, we present our investigations on four-level resistance states, giant tunneling electroresistance (TER) due to interfacial magnetoelectric coupling, and ferroelectric control of spin polarized tunneling in MFTJs. Coexistence of large tunneling magnetoresistance and TER has been observed …
Explorations For Efficient Reversible Barrel Shifters And Their Mappings In Qca Nanocomputing, 2015 University of Kentucky
Explorations For Efficient Reversible Barrel Shifters And Their Mappings In Qca Nanocomputing, Ke Chen
Theses and Dissertations--Electrical and Computer Engineering
This thesis is based on promising computing paradigm of reversible logic which generates unique outputs out of the inputs and. Reversible logic circuits maintain one-to-one mapping inside of the inputs and the outputs. Compared to the traditional irreversible computation, reversible logic circuit has the advantage that it successfully avoids the information loss during computations. Also, reversible logic is useful to design ultra-low-power nanocomputing circuits, circuits for quantum computing, and the nanocircuits that are testable in nature. Reversible computing circuits require the ancilla inputs and the garbage outputs. Ancilla input is the constant input in reversible circuits. Garbage output is the …
Development Of A Lab-On-A-Chip Device For Rapid Nanotoxicity Assessment In Vitro, 2014 Engineering
Development Of A Lab-On-A-Chip Device For Rapid Nanotoxicity Assessment In Vitro, Pratikkumar Shah
FIU Electronic Theses and Dissertations
Increasing useof nanomaterials in consumer products and biomedical applications creates the possibilities of intentional/unintentional exposure to humans and the environment. Beyond the physiological limit, the nanomaterialexposure to humans can induce toxicity. It is difficult to define toxicity of nanoparticles on humans as it varies by nanomaterialcomposition, size, surface properties and the target organ/cell line. Traditional tests for nanomaterialtoxicity assessment are mostly based on bulk-colorimetric assays. In many studies, nanomaterials have found to interfere with assay-dye to produce false results and usually require several hours or days to collect results. Therefore, there is a clear need for alternative tools that can …
Radiation-Induced Effects In Chalcogenide-Based Memory Devices And Films, 2014 Boise State University
Radiation-Induced Effects In Chalcogenide-Based Memory Devices And Films, Kasandra Wolf
Boise State University Theses and Dissertations
Continued scaling of memory devices has produced many issues for the current foremost non-volatile memory—the flash memory—leading to the emergence of a wide variety of alternative memory solutions. Redox Conductive Bridge Memory (RCBM) is one such solution that has shown great promise in recent years. However, the performance of these devices under radiation conditions has not been explored in detail. This work investigates the effects of x-rays and electron bombardment on chalcogenide glasses and RCBM devices based on these materials.
RCBM devices are a form of Resistance Change Memory, which rely on two distinct resistive states to represent the binary …