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Rao Tummala

Other affiliations: Qualcomm, IBM, AVX Corporation  ...read more
Bio: Rao Tummala is an academic researcher from Georgia Institute of Technology. The author has contributed to research in topics: Interposer & Capacitor. The author has an hindex of 43, co-authored 623 publications receiving 11663 citations. Previous affiliations of Rao Tummala include Qualcomm & IBM.


Papers
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Proceedings ArticleDOI
26 May 2015
TL;DR: In this paper, the characterization of electrical properties of glass/ZIF stack-up and transmission lines up to 50 GHz is presented, for the first time, and the results show promising RF performance of glass and T.L on glass up to 10 GHz.
Abstract: This paper presents, for the first time, the characterization of electrical properties of Glass/ZIF stack-up and transmission lines on glass/ZIF up to 50 GHz. Ring resonators, co-planar wave guide (CPW), CPWs with Thru-Package-Vias (TPVs) and microstrip to CPW transitions are designed, fabricated and measured on a 300/33 µm glass/ZIF substrate. The Short-Open-Load-Through (SOLT) calibration technique was used to measure the fabricated structures. Measurements show promising RF performance of glass and T.L on glass up to 50 GHz. An insertion loss of 0.05 dB/mm at 20 GHz and 0.12 dB/mm at 50 GHz for a CPW line has been measured. The microstrip to CPW transition exhibited 0.24 dB/mm of loss and a thru-package-via exhibited a loss of 0.34 dB at 50 GHz. A dielectric constant of 4.95 and loss tangent of 0.012 at 50 GHz is also reported.

11 citations

Patent
26 May 2005
TL;DR: Nano-structured interconnect formation and a reworkable bonding process using solder films is demonstrated at a very fine pitch as mentioned in this paper, which can be used for pushing the limits of current flip chip bonding in terms of pitch, number of I/Os, superior combination of electrical and mechanical properties as well as reworkability.
Abstract: Nano-structured interconnect formation and a reworkable bonding process using solder films Large area fabrication of nano-structured interconnects is demonstrated at a very fine pitch This technology can be used for pushing the limits of current flip chip bonding in terms of pitch, number of I/Os, superior combination of electrical and mechanical properties as well as reworkability Sol-gel and electroless processes were developed to demonstrate film bonding interfaces between metallic pads and nano interconnects Solution-derived nano-solder technology is an attractive low-cost method for several applications such as MEMS hermetic packaging, compliant interconnect bonding and bump-less nano-interconnects

11 citations

Journal ArticleDOI
TL;DR: Nanopackaging, therefore, should transform the handheld devices of today to become megafunctional convergent systems with computing, communications, and sensor capabilities.
Abstract: The vision of GT-PRC's 3D systems is to go beyond 3D ICs to miniaturize the entire electronic or bioelectronic system components to nanoscale, such as passive components, system interconnections, thermal structures, and power supplies. Recent advances in the synthesis of nanomaterials with outstanding properties combined with novel processing technologies can lead to highly miniaturized, highly functional, and lowcost components and systems (Table 2). The nano to microscale wiring on system packages, off-chip nanointerconnections, and functional nanocomponents for RF, digital, and biofunctions will eventually migrate systems to nanoscale. Nanopackaging, therefore, should transform the handheld devices of today to become megafunctional convergent systems with computing, communications, and sensor capabilities.

11 citations

Journal ArticleDOI
TL;DR: In this paper, the feasibility of integration of passive components on glass substrates has been investigated using a case study of an active filter circuit with resistors, capacitors, and inductors.
Abstract: Integral passive is an emerging technology which is currently perceived as a possible alternative to the discrete passive technology in fulfilling the next generation packaging needs. Although discrete surface mount passive components (resistors, capacitors, and inductors) have been well characterized, the development of integral passive components suitable for co-integration on the board level is relatively recent. Since in some applications the number of passive components can exceed the number and the area of IC chips on a circuit board or in a package, such integration of passive components would be necessary to substantially eliminate part count and reduce device area. To address these issues, integration technology for passive elements in the same manner as for transistors is necessary. In addition, the fabrication sequence of all integral passive components should be mutually compatible for co-integration on the same substrate. In this paper, materials and fabrication issues for passive elements such as resistors (R), capacitors (C), and inductors (L) and the feasibility of integration of these fabricated passive components on glass substrates have been addressed. An active filter circuit has been selected for a case study for R, L, and C co-integration. This passive module contains eleven resistors, four capacitors, and four inductors, and is fabricated using MCM-D (multichip module-deposited) compatible processes. A variety of materials appropriate for fabrication of integral passives in a mutually compatible fashion were investigated, including chromium and nickel-chromium resistors, composites of high dielectric constant materials in epoxies for capacitor dielectrics, and composites of magnetic ferrite particles in polyimides for inductor core and shielding. The fabricated devices showed good agreement between the design values and the corresponding measured values. It is anticipated that some of these materials and fabrication processes can be implemented for the MCM-L (multichip module-laminate) compatible packaging. © 2000 Kluwer Academic Publishers

11 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: Shape-memory polymers as discussed by the authors are an emerging class of active polymers that can change their shape in a predefined way from shape A to shape B when exposed to an appropriate stimulus.

1,575 citations

Journal ArticleDOI
14 Feb 2008-Nature
TL;DR: This work establishes a methodology for scavenging light-wind energy and body-movement energy using fabrics and presents a simple, low-cost approach that converts low-frequency vibration/friction energy into electricity using piezoelectric zinc oxide nanowires grown radially around textile fibres.
Abstract: Nanodevices don't use much energy, and if the little they do need can be scavenged from vibrations associated with foot steps, heart beats, noises and air flow, a whole range of applications in personal electronics, sensing and defence technologies opens up. Energy gathering of that type requires a technology that works at low frequency range (below 10 Hz), ideally based on soft, flexible materials. A group working at Georgia Institute of Technology has now come up with a system that converts low-frequency vibration/friction energy into electricity using piezoelectric zinc oxide nanowires grown radially around textile fibres. By entangling two fibres and brushing their associated nanowires together, mechanical energy is converted into electricity via a coupled piezoelectric-semiconductor process. This work shows a potential method for creating fabrics which scavenge energy from light winds and body movement. A self-powering nanosystem that harvests its operating energy from the environment is an attractive proposition for sensing, personal electronics and defence technologies1. This is in principle feasible for nanodevices owing to their extremely low power consumption2,3,4,5. Solar, thermal and mechanical (wind, friction, body movement) energies are common and may be scavenged from the environment, but the type of energy source to be chosen has to be decided on the basis of specific applications. Military sensing/surveillance node placement, for example, may involve difficult-to-reach locations, may need to be hidden, and may be in environments that are dusty, rainy, dark and/or in deep forest. In a moving vehicle or aeroplane, harvesting energy from a rotating tyre or wind blowing on the body is a possible choice to power wireless devices implanted in the surface of the vehicle. Nanowire nanogenerators built on hard substrates were demonstrated for harvesting local mechanical energy produced by high-frequency ultrasonic waves6,7. To harvest the energy from vibration or disturbance originating from footsteps, heartbeats, ambient noise and air flow, it is important to explore innovative technologies that work at low frequencies (such as <10 Hz) and that are based on flexible soft materials. Here we present a simple, low-cost approach that converts low-frequency vibration/friction energy into electricity using piezoelectric zinc oxide nanowires grown radially around textile fibres. By entangling two fibres and brushing the nanowires rooted on them with respect to each other, mechanical energy is converted into electricity owing to a coupled piezoelectric–semiconductor process8,9. This work establishes a methodology for scavenging light-wind energy and body-movement energy using fabrics.

1,473 citations

Journal ArticleDOI
TL;DR: This work demonstrates the vertical and lateral integration of ZnO nanowires into arrays that are capable of producing sufficient power to operate real devices and uses the vertically integrated nanogenerator to power a nanowire pH sensor and a Nanowire UV sensor, thus demonstrating a self-powered system composed entirely of nanowiring.
Abstract: The lateral and vertical integration of ZnO piezoelectric nanowires allows for voltage and power outputs sufficient to power nanowire-based sensors.

1,465 citations

Journal ArticleDOI
TL;DR: In this paper, the authors focus on the important role and challenges of high-k polymer-matrix composites (PMC) in new technologies and discuss potential applications of highk PMC.

1,412 citations