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- Data visualisation (2)
- Digital forensics (2)
- MO imaging (2)
- Magneto-optic (MO) materials (2)
- Thin films (2)
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- Antenna radiation patterns;barium compounds;coplanar waveguides;dielectric materials;dielectric thin films;ferroelectric devices;impedance matching;slot antennas;strontium compounds;varactors;Ba(1-x)SrxTiO3;CPW antenna structure;DC voltage;E-plane co-polarized patterns;H-plane co-polarized patterns;antenna miniaturization;ferroelectric BST thin film varactors;ferroelectric varactor loadings;frequency 5.3 GHz to 5.8 GHz;high dielectric constant materials;impedance matching;miniaturized antenna;reconfigurable CPW square-ring slot antenna;reconfigurable coplanar waveguide square-ring slot antenna;resonant frequency;tuning stub;Coplanar waveguides;Iron;Probes;Slot antennas;Varactors;Antenna miniaturization;coplanar waveguide (CPW) antenna;ferroelectric thin film;ferroelectric varactor;reconfigurable antenna;slot loop antenna;varactor loadings (1)
- Ba(Zr (1)
- Barium compounds;dielectric hysteresis;electric impedance;ferroelectric capacitors;ferroelectric thin films;lead compounds;strontium compounds;thin film capacitors;varactors;(BaSr)TiO3;EMC decoupling;PZT;electromagnetic compatibility;equivalent circuit model;ferroelectric hysteresis;impedance;insertion loss;paraelectric based integrated varactors;series resistance;thin-film ferroelectric capacitors;Capacitors;Electrical resistance measurement;Electromagnetic compatibility;Electromagnetic measurements;Ferroelectric materials;Impedance measurement;Insertion loss;Loss measurement;Thin film circuits;Transistors;Algorithms;Barium Compounds;Electric Capacitance;Electrochemistry;Electromagnetic Phenomena;Ferric Compounds;Oxides;Strontium;Titanium (1)
- Capacitance;dielectric hysteresis;dielectric polarisation;ferroelectric coercive field;ferroelectric switching;ferroelectric thin films;Landau-Khalatnikov model;coercive voltage;hysteresis loop;polarization switching;thin-film ferroelectric capacitance;voltage dependence;Capacitance measurement;Capacitance-voltage characteristics;Ferroelectric materials;Hysteresis;Polarization;Transistors;Voltage (1)
- Capacitive shunt switch (1)
- Capacitive test structure (1)
- Capacitors (1)
- Chemical Engineering (1)
- Coplanar waveguide transmission line (1)
- Coplanar waveguide transmission lines (1)
- Coplanar waveguides;current density;printed circuits;strip lines;common-mode radiated emissions;conformal mapping;coplanar stripline printed circuit boards;current density distribution;net ground plane inductance;Conductors;Current density;Current distribution;Inductance;Microstrip;Printed circuits;Stripline;Common-mode radiated emissions;conformal mapping;coplanar stripline;net ground plane inductance (1)
- DNA (1)
- DNA-based biopolymers; dielectric properties; electrical transport in biopolymers; electric force microscopy Read More: http://www.worldscientific.com/doi/abs/10.1142/S179329200900154X (1)
- DNA;coplanar waveguide components;dielectric materials;magnesium compounds;microwave photonics;molecular electronics;polymer films;thin films;0.1 dB;0.5 dB;10 to 30 GHz;DNA based polymers;coplanar waveguide lines;dielectric constant;microwave dielectric properties;microwave frequencies;microwave photonics;polymer thin films;propagation constants;Conductors;Coplanar waveguides;DNA;Dielectrics;Microwave frequencies;Nonlinear optics;Optical films;Optical polymers;Optical waveguides;Polymer films;Coplanar waveguide (CPW) lines;dielectric deoxyribonucleic acid (DNA) based polymers;microwave characterization;microwave photonics (1)
- Dielectric (1)
- Dielectric hysteresis;dielectric polarisation;ferroelectric switching;ferroelectric thin films;lead compounds;space charge;PZT thin films;Pb(ZrTi)O3;Sawyer-Tower circuit;equivalent input impedance;ferroelectric thin films;hysteresis loop;leakage resistance;linear polarization;remnant polarization;space charge effects;switching polarization;Electrical resistance measurement;Ferroelectric materials;Hysteresis;Impedance;Iron;Polarization;Shape;Space charge;Thin film circuits;Transistors (1)
- Dielectric thin films (1)
- Distributed transmission line phase shifter (1)
- Dopant-ion charges (1)
- Elastic moduli (1)
- Electric-field distribution in ferroelectrics (1)
- Electromagnetic bandgap (1)
- Electromagnetic bandgap (EBG); coplanar waveguide (CPW); ferroelectric varactor; tunability (1)
- Epitaxial (1)
- Ferroelectric (1)
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Articles 1 - 30 of 39
Full-Text Articles in Engineering
New Class Of Garnet Nanocomposites For Use In Magnetic Photonic Crystals Prepared By Rf Magnetron Co-Sputtering, Mohammad Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh
New Class Of Garnet Nanocomposites For Use In Magnetic Photonic Crystals Prepared By Rf Magnetron Co-Sputtering, Mohammad Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh
Mikhail Vasiliev
No abstract provided.
Magneto-Optical Visualisation For High-Resolution Forensic Data Recovery Using Advanced Thin Film Nano-Materials, M Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh, Craig Valli
Magneto-Optical Visualisation For High-Resolution Forensic Data Recovery Using Advanced Thin Film Nano-Materials, M Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh, Craig Valli
Mikhail Vasiliev
We develop and characterise new high-performance nano-engineered magneto-optic materials for use in laser-microscopy- based magnetic field visualisers featuring high sensitivity and resolution, low cost and small size. This type of visualisers will make it possible for forensic experts to recover erased data previously stored in high- and ultrahigh-density magnetic disks and hard disk drives.
Technological Challenges Of 1-Dimensional Magnetic Photonic Crystals, Mikhail Vasiliev, Kamal Alameh, Dmitry E. Balabanov, Vladimir I. Burkov, V. V. Koledov, Viacheslav A. Kotov, V. G. Shavrov, Anotoly K. Zvezdin
Technological Challenges Of 1-Dimensional Magnetic Photonic Crystals, Mikhail Vasiliev, Kamal Alameh, Dmitry E. Balabanov, Vladimir I. Burkov, V. V. Koledov, Viacheslav A. Kotov, V. G. Shavrov, Anotoly K. Zvezdin
Mikhail Vasiliev
Visible-region magnetic photonic crystals (MPC) designed for higher-order bandgap operation have been proposed to overcome the technological restrictions originating from the strong thickness dependency of the individual magnetic layer properties observed in MPC structures.
Nano-Engineered High-Performance Magneto-Optic Garnet Materials, Mohammad Nur-E-Alam, Mikhail Vasiliev, Viacheslav Kotov, Kamal Alameh
Nano-Engineered High-Performance Magneto-Optic Garnet Materials, Mohammad Nur-E-Alam, Mikhail Vasiliev, Viacheslav Kotov, Kamal Alameh
Mikhail Vasiliev
No abstract provided.
Nanostructured Engineered Materials With High Magneto-Optic Performance For Integrated Photonics Applications, Mikhail Vasiliev, Kamal Alameh, Viacheslav Kotov, Yong-Tak Lee
Nanostructured Engineered Materials With High Magneto-Optic Performance For Integrated Photonics Applications, Mikhail Vasiliev, Kamal Alameh, Viacheslav Kotov, Yong-Tak Lee
Mikhail Vasiliev
No abstract provided.
New Class Of Garnet Nanocomposites For Use In Magnetic Photonic Crystals Prepared By Rf Magnetron Co-Sputtering, Mohammad Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh
New Class Of Garnet Nanocomposites For Use In Magnetic Photonic Crystals Prepared By Rf Magnetron Co-Sputtering, Mohammad Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh
Mikhail Vasiliev
No abstract provided.
Magneto-Optical Visualisation For High-Resolution Forensic Data Recovery Using Advanced Thin Film Nano-Materials, M Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh, Craig Valli
Magneto-Optical Visualisation For High-Resolution Forensic Data Recovery Using Advanced Thin Film Nano-Materials, M Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh, Craig Valli
Mikhail Vasiliev
We develop and characterise new high-performance nano-engineered magneto-optic materials for use in laser-microscopy- based magnetic field visualisers featuring high sensitivity and resolution, low cost and small size. This type of visualisers will make it possible for forensic experts to recover erased data previously stored in high- and ultrahigh-density magnetic disks and hard disk drives.
Technological Challenges Of 1-Dimensional Magnetic Photonic Crystals, Mikhail Vasiliev, Kamal Alameh, Dmitry E. Balabanov, Vladimir I. Burkov, V. V. Koledov, Viacheslav A. Kotov, V. G. Shavrov, Anotoly K. Zvezdin
Technological Challenges Of 1-Dimensional Magnetic Photonic Crystals, Mikhail Vasiliev, Kamal Alameh, Dmitry E. Balabanov, Vladimir I. Burkov, V. V. Koledov, Viacheslav A. Kotov, V. G. Shavrov, Anotoly K. Zvezdin
Mikhail Vasiliev
Visible-region magnetic photonic crystals (MPC) designed for higher-order bandgap operation have been proposed to overcome the technological restrictions originating from the strong thickness dependency of the individual magnetic layer properties observed in MPC structures.
Nano-Engineered High-Performance Magneto-Optic Garnet Materials, Mohammad Nur-E-Alam, Mikhail Vasiliev, Viacheslav Kotov, Kamal Alameh
Nano-Engineered High-Performance Magneto-Optic Garnet Materials, Mohammad Nur-E-Alam, Mikhail Vasiliev, Viacheslav Kotov, Kamal Alameh
Mikhail Vasiliev
No abstract provided.
High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas Wyrobek, Oden Warren, Jason Hattrick-Simpers, Olubenga Famodu, Ichiro Takeuchi
High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas Wyrobek, Oden Warren, Jason Hattrick-Simpers, Olubenga Famodu, Ichiro Takeuchi
Jason R. Hattrick-Simpers
We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memoryalloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memoryalloy composition region, located around the Heusler composition (Ni2MnAl), was found to display significant departure in these mechanical properties from the rest of the composition spread. In particular, the modulus and the hardness values are lower for the martensite region than those of the rest of the phase diagram.
Tunable Electromagnetic Bandgap Performance Of Coplanar Waveguides Periodically Loaded By Ferroelectric Varactors, D. Kuylenstierna, Guru Subramanyam, A. Vorobiev, S. Gevorgian
Tunable Electromagnetic Bandgap Performance Of Coplanar Waveguides Periodically Loaded By Ferroelectric Varactors, D. Kuylenstierna, Guru Subramanyam, A. Vorobiev, S. Gevorgian
Guru Subramanyam
To achieve tunable electromagnetic bandgap (EBG) performance, ferroelectric varactors are considered, in LC circuits, for periodically loading coplanar waveguides (CPWs). Asymmetric or symmetric tuning of the bandgap width may be achieved by changing the capacitance of the varactors in the LC circuits. To validate this concept, tunable EBG arrays based on silicon substrate CPWs, including thin film SrTiO3 (STO) varactors, are fabricated and tested experimentally. The EBGs are designed so that the first band gap starts between 20 and 30 GHz. Up to 10% tuning is achieved, under 20-V DC applied bias, in the EBG structures.
A New Method For Electrical Characterization Of Ferroelectric Thin Films At Microwave Frequencies, Guru Subramanyam
A New Method For Electrical Characterization Of Ferroelectric Thin Films At Microwave Frequencies, Guru Subramanyam
Guru Subramanyam
Read More: http://www.worldscientific.com/doi/abs/10.1142/S179329200900154X
Capacitance Of Thin-Film Ferroelectrics Under Different Drive Signals, Huadong Li, Guru Subramanyam
Capacitance Of Thin-Film Ferroelectrics Under Different Drive Signals, Huadong Li, Guru Subramanyam
Guru Subramanyam
Thin-film ferroelectric capacitance can be obtained by 2 different methods. Capacitance obtained using the derivative of its hysteresis loop is related to large applied signals and can be called the large-signal capacitance. Capacitance measured directly with a small, applied ac signal together with a slow changing dc bias is called the small-signal capacitance. This paper investigated the voltage dependence of the large- and small-signal capacitances. Measurements show that the large-signal C-V curve of thin-film ferroelectrics has much sharper peaks and higher peak values than the small-signal C-V curve. Analyses based on the Landau-Khalatnikov model shows that practical small-signal capacitance is …
Effect Of External Electrical Stimuli On Dna-Based Biopolymers, Guru Subramanyam, Carrie Bartsch, James Grote, Rajesh Naik, Lawrence Brott, Morley Stone, Angela Campbell
Effect Of External Electrical Stimuli On Dna-Based Biopolymers, Guru Subramanyam, Carrie Bartsch, James Grote, Rajesh Naik, Lawrence Brott, Morley Stone, Angela Campbell
Guru Subramanyam
Biopolymers, such as deoxyribonucleic acid-hexadecyltrimethyl ammonium chloride (DNA-CTMA) and bovine serum albumin-polyvinyl alcohol (BSA-PVA), were studied using a novel capacitive test structure. A variety of external electrical stimuli were applied, including a low frequency alternating current signal and a rf/microwave frequency signal combined with a DC bias. The dynamic responses of the DNA-based biopolymer to the external stimuli are presented in this paper. The electrical transport measurements support the space-charge-limited conduction and the low frequency capacitance–voltage (CV) measurements showed large depletion layer capacitance at the Au–biopolymer interface, at 20 Hz, and the capacitance approaching bulk values at 1 MHz. Electric …
Thermally Controlled Vanadium Dioxide Thin Film Microwave Devices, Guru Subramanyam, E. Shin, D. Brown, H. Yue
Thermally Controlled Vanadium Dioxide Thin Film Microwave Devices, Guru Subramanyam, E. Shin, D. Brown, H. Yue
Guru Subramanyam
No abstract provided.
Design Of A Si Mmic Compatible Ferroelectric Varactor Shunt Switch For Microwave Applications, Faruque Ahamed, Guru Subramanyam
Design Of A Si Mmic Compatible Ferroelectric Varactor Shunt Switch For Microwave Applications, Faruque Ahamed, Guru Subramanyam
Guru Subramanyam
This paper describes a capacitive shunt switch, based on ferroelectric varactors as a potential replacement for RF MEMS switches for microwave applications. Our implementation is based on a coplanar waveguide (CPW) transmission line shunted by a ferroelectric varactor. The novelty in the implementation comes from the elimination of any moving parts (as in MEMS switches) for switching. The concept of switching ON and OFF is based on the dielectric tunability of the ferroelectric material of barium strontium titanium oxide (BST) thin-films. From electromagnetic simulations performed, the isolation of the switch between 20 and 40 GHz (OFF state S21) is better …
Rf Performance Evaluation Of Ferroelectric Varactor Shunt Switches, Guru Subramanyam, Faruque Ahamed, Rand Biggers, Robert Neidhard, Edward Nykiel, John Ebel, Richard Strawser, Keith Stamper, Mark Calcatera
Rf Performance Evaluation Of Ferroelectric Varactor Shunt Switches, Guru Subramanyam, Faruque Ahamed, Rand Biggers, Robert Neidhard, Edward Nykiel, John Ebel, Richard Strawser, Keith Stamper, Mark Calcatera
Guru Subramanyam
No abstract provided.
Ferroelectric Batio3/Srtio3 Multilayered Thin Films For Room-Temperature Tunable Microwave Elements, Ming Liu, Chunrui Ma, Gregory Collins, Jian Liu, Chonglin Chen, Andy D. Alemayehu, Guru Subramanyam, Ying Ding, Jianghua Chen, Chao Dai, Yuan Lin, Melanie W. Cole
Ferroelectric Batio3/Srtio3 Multilayered Thin Films For Room-Temperature Tunable Microwave Elements, Ming Liu, Chunrui Ma, Gregory Collins, Jian Liu, Chonglin Chen, Andy D. Alemayehu, Guru Subramanyam, Ying Ding, Jianghua Chen, Chao Dai, Yuan Lin, Melanie W. Cole
Guru Subramanyam
Ferroelectric BaTiO3/SrTiO3 with optimized c-axis-oriented multilayered thin films were epitaxially fabricated on (001) MgO substrates. The microstructural studies indicate that the in-plane interface relationships between the films as well as the substrate are determined to be (001)SrTiO3//(001)BaTiO3//(001)MgO and [100]SrTiO3//[100]BaTiO3//[100]MgO. The microwave (5 to 18 GHz) dielectric measurements reveal that the multilayered thin films have excellent dielectric properties with large dielectric constant, low dielectric loss, and high dielectric tunability, which suggests that the as-grown ferroelectric multilayered thin films can be developed for room-temperature tunable microwave elements and related device applications.
A Reconfigurable Cpw Bow-Tie Antenna Using An Integrated Ferroelectric Thin Film Varactor, K. C. Pan, Dustin Brown, Guru Subramanyam, R. Penno, H. Jiang, C. H. Zhang, M. Patterson, David Kuhl, Kevin Leedy, Charles Cerny
A Reconfigurable Cpw Bow-Tie Antenna Using An Integrated Ferroelectric Thin Film Varactor, K. C. Pan, Dustin Brown, Guru Subramanyam, R. Penno, H. Jiang, C. H. Zhang, M. Patterson, David Kuhl, Kevin Leedy, Charles Cerny
Guru Subramanyam
A novel printed antenna with a frequency reconfigurable feed network is presented. The antenna consists of a bowtie structure patch radiating element in the inner space of an annulus that is on a nongrounded substrate with a ferroelectric (FE) Barium Strontium Titanate (BST) thin film. The bowtie patch is fed by a coplanar waveguide (CPW) transmission line that also includes a CPW-based BST shunt varactor. Reconfiguration of the compact 8 mm × 8 mm system has been demonstrated by shifting the antenna system’s operating frequency 500 MHz in the 7–9 GHz band by applying a DC voltage bias.
Large Area Bst Thin Films For Microwave Applications Deposited By Pulsed Laser Ablation, C. Varanasi, K. Leedy, D. Tomich, Guru Subramanyam
Large Area Bst Thin Films For Microwave Applications Deposited By Pulsed Laser Ablation, C. Varanasi, K. Leedy, D. Tomich, Guru Subramanyam
Guru Subramanyam
Large area Ba1 − xSrxTiO3 (BST) thin films with x = 0.4 or x = 0.5 were deposited on 75 mm diameter Si wafers in a pulsed laser deposition (PLD) chamber enabling full-wafer device fabrication using standard lithography. The deposition conditions were re-optimized for large PLD chambers to obtain uniform film thickness, grain size, crystal structure, orientation, and dielectric properties of BST films. X-ray diffraction and microstructural analyses on the BST films grown on Pt/Au/Ti electrodes deposited on SiO2/Si wafers revealed films with (110) preferred orientation with a grain size < 100 nm. An area map of the thickness and crystal …
Highly Efficient Quantum-Dot Light Emitting Diodes With Dna-Ctma As Combined Hole Transporting And Electron-Blocking Layer, Q. Sun, Guru Subramanyam, Liming Dai, M. Check, A. Campbell, Rajesh Naik, James Grote, Yongqiang Wang
Highly Efficient Quantum-Dot Light Emitting Diodes With Dna-Ctma As Combined Hole Transporting And Electron-Blocking Layer, Q. Sun, Guru Subramanyam, Liming Dai, M. Check, A. Campbell, Rajesh Naik, James Grote, Yongqiang Wang
Guru Subramanyam
Owing to their narrow bright emission band, broad size-tunable emission wavelength, superior photostability, and excellent flexible-substrate compatibility, light-emitting diodes based on quantum dots (QD-LEDs) are currently under intensive research and development for multiple consumer applications including flat-panel displays and flat lighting. However, their commercialization is still precluded by the slow development to date of efficient QD-LEDs as even the highest reported efficiency of 2.0% cannot favorably compete with their organic counterparts. Here, we report QD-LEDs with a record high efficiency (∼4%), high brightness (∼6580 cd/m2), low turn-on voltage (∼2.6 V), and significantly improved color purity by simply using deoxyribonucleic acid …
Enhanced Dielectric Properties Of (Ba,Sr)Tio3//Ba(Zr,Ti)O-3 Heterostructures With Optimized Structure Design, Ming Liu, Jian Liu, Chunrui Ma, Gregory Collins, Chonglin Chen, Andy Alemayehu, Guru Subramanyam, Jie He, Jiechao Jiang, Efstathios Meletis, Amar Bhalla
Enhanced Dielectric Properties Of (Ba,Sr)Tio3//Ba(Zr,Ti)O-3 Heterostructures With Optimized Structure Design, Ming Liu, Jian Liu, Chunrui Ma, Gregory Collins, Chonglin Chen, Andy Alemayehu, Guru Subramanyam, Jie He, Jiechao Jiang, Efstathios Meletis, Amar Bhalla
Guru Subramanyam
Environment-friendly ferroelectric Mn:BST//Mn:BZT heterostructures were epitaxially deposited on (001) MgO substrates by pulsed laser deposition with different combination ratios of Mn:BST over Mn:BZT, 2.5:7.5; 1:1; and 7.5:2.5. The microstructural studies indicate that the in-plane interface relationships between the heterostructures and the substrate are determined to be (001)Mn:BST//(001)Mn:BZT//(001)MgO and [100]Mn:BST//[100]Mn:BZT//[100]MgO. The Ku band microwave (15.5–18 GHz) dielectric property characterizations show that the dielectric constant, dielectric loss, and tunabilities of the heterostructures are highly dependent upon the sequences of Mn:BST to Mn:BZT. The optimized dielectric tunability with a low loss tangent was found to be 58.1%–74.4% under the combination ratio of 1:1 …
A New Ferroelectric Varactor Shunt Switch For Microwave And Millimeterwave Reconfigurable Circuits, Guru Subramanyam, Faruque Ahamed, Rand Biggers, Angela Campbell, Robert Neidhard, Edward Nykiel, Rebecca Cortez, Keith Stamper, Mark Calcatera
A New Ferroelectric Varactor Shunt Switch For Microwave And Millimeterwave Reconfigurable Circuits, Guru Subramanyam, Faruque Ahamed, Rand Biggers, Angela Campbell, Robert Neidhard, Edward Nykiel, Rebecca Cortez, Keith Stamper, Mark Calcatera
Guru Subramanyam
This paper presents a ferroelectric varactor shunt switch which can be useful for microwave/millimeterwave switching as well as for the design of reconfigurable circuits. The device operation is based on nonlinear dielectric tunability of a ferroelectric thin-film sandwiched between two metal layers in the parallel plate configuration. A CPW based design allows for MMIC compatible shunt switches with low insertion loss and high isolation. Experimental performance of the varactor shunt switch indicates good switching performance with ~24 dB isolation @41 GHz, and insertion loss below 7 dB up to 45 GHz.
Ferroelectric Thin-Film Based Two-Dimensional Electromagnetic Structures, U. Khan, Guru Subramanyam, S. Gevorgian, A. Vorobiev
Ferroelectric Thin-Film Based Two-Dimensional Electromagnetic Structures, U. Khan, Guru Subramanyam, S. Gevorgian, A. Vorobiev
Guru Subramanyam
A two-dimensional electromagnetic bandgap structure has been developed using ferroelectric thin-films. Using lumped inductors and parallel plate capacitors a planar structure is developed which creates a bandgap in the 20–40 GHz range, as demonstrated by experimental results. The ferroelectric material Ba0.6Sr0.4TiO3 (BST) is used in the form of a thin-film between patterned layers of gold to form capacitors on a 500 μm thick high-resistivity Si substrate. A meander line based design is used to form the two-dimensional surface which provides biasing pathways to the varactors. The concept is simulated and experimentally verified using a coplanar waveguide based device in which …
Performance Of Thin-Film Ferroelectric Capacitors For Emc Decoupling, Huadong Li, Guru Subramanyam
Performance Of Thin-Film Ferroelectric Capacitors For Emc Decoupling, Huadong Li, Guru Subramanyam
Guru Subramanyam
This paper studied the effects of thin-film ferroelectrics as decoupling capacitors for electromagnetic compatibility applications. The impedance and insertion loss of PZT capacitors were measured and compared with the results from commercial off-the-shelf capacitors. An equivalent circuit model was extracted from the experimental results, and a considerable series resistance was found to exist in ferroelectric capacitors. This resistance gives rise to the observed performance difference around series resonance between ferroelectric PZT capacitors and normal capacitors. Measurements on paraelectric (Ba,Sr)TiO3-based integrated varactors do not show this significant resistance. Some analyses were made to investigate the mechanisms, and it was …
A New Capacitive Test Structure For Microwave Characterization Of Biopolymers, Carrie M. Bartsch, Guru Subramanyam, James Grote, Frank K. Hopkins, Lawrence L. Brott, Rajesh R. Naik
A New Capacitive Test Structure For Microwave Characterization Of Biopolymers, Carrie M. Bartsch, Guru Subramanyam, James Grote, Frank K. Hopkins, Lawrence L. Brott, Rajesh R. Naik
Guru Subramanyam
A new capacitive test structure, containing a parallel plate capacitor with coplanar waveguide feed lines, was used for microwave characterization of biopolymers for the first time. Microwave dielectric properties were obtained for the biopolymers as a function of dc bias and temperature by performing on-wafer microwave measurements. Dielectric tunability was observed with applied dc bias in the biopolymers tested.
A Memristor Device Model, Chris Yakopcic, Tarek Taha, Guru Subramanyam
A Memristor Device Model, Chris Yakopcic, Tarek Taha, Guru Subramanyam
Guru Subramanyam
This letter proposes a new mathematical model for memristor devices. It builds on existing models and is correlated against several published device characterizations. This letter identifies significant discrepancies between the existing models and published device characterization data. The proposed model addresses these discrepancies. In particular, it allows modeling of memristor-based neuromorphic systems.
Microwave Characterization Of Nanostructured Ferroelectric Ba0.6sr0.4tio3 Thin Films Fabricated By Pulsed Laser Deposition, Angela Campbell, Rand Biggers, Guru Subramanyam, Gregory Kozlowski, Richard Kleismit, Hollie Zate, Simon Hopkins, Bartek Glowacki, Bonnie Riehl, Timothy Peterson
Microwave Characterization Of Nanostructured Ferroelectric Ba0.6sr0.4tio3 Thin Films Fabricated By Pulsed Laser Deposition, Angela Campbell, Rand Biggers, Guru Subramanyam, Gregory Kozlowski, Richard Kleismit, Hollie Zate, Simon Hopkins, Bartek Glowacki, Bonnie Riehl, Timothy Peterson
Guru Subramanyam
A series of nanostructured ferroelectric thin films of barium strontium titanate were fabricated using a pulsed laser deposition system with real-time in situ process control. Pulsed laser deposition parameters were controlled during the growth of nanostructured thin films for use in the development of high frequency tunable microwave devices. The thin films were all grown at the same substrate temperature and laser beam energy density, but the chamber oxygen partial pressure (COPP) was varied systematically from 19 mTorr through 1000 Torr. Structural and electromagnetic characterization was performed using atomic force microscopy and evanescent microwave microscopy, respectively. Atomic force microscopy showed …
Microwave Dielectric Properties Of Dna Based Polymers Between 10 And 30 Ghz, Guru Subramanyam, E. Heckman, James Grote, K. Hopkins
Microwave Dielectric Properties Of Dna Based Polymers Between 10 And 30 Ghz, Guru Subramanyam, E. Heckman, James Grote, K. Hopkins
Guru Subramanyam
Deoxyribonucleic acid (DNA) based polymer thin-films were characterized at microwave frequencies for the first time. The dielectric properties of the film were extracted from comparison of the propagation constants of the co-planar waveguide (CPW) lines on bare MgO substrates and the DNA based films on MgO substrates. The insertion loss introduced by the DNA film is only 0.1 dB at 10 GHz and 0.5 dB at 30 GHz. The relative dielectric constant of the DNA based film averages to four at microwave frequencies, and the loss-tangent was below 0.1 up to 30 GHz.
Closed-Form Expression For The Net Ground Plane Inductance Of Coplanar Stripline Pcbs, Li Huadong, Guru Subramanyam
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.