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Full-Text Articles in Engineering
Asymptotic Spectral Efficiency Of Multiantenna Links In Wireless Networks With Limited Tx Csi, Siddhartan Govindasamy, Daniel Bliss, David Staelin
Asymptotic Spectral Efficiency Of Multiantenna Links In Wireless Networks With Limited Tx Csi, Siddhartan Govindasamy, Daniel Bliss, David Staelin
Siddhartan Govindasamy
An asymptotic technique is presented for finding the spectral efficiency of multiantenna links in spatially distributed wireless networks where transmitters have channel-state-information (CSI) corresponding to their target receiver. Transmitters are assumed to transmit independent data streams on a limited number of channel modes which limits the rank of transmit covariance matrices. An approximation for the spectral efficiency in the interference-limited regime as a function of link-length, interferer density, number of antennas per receiver and transmitter, number of transmit streams, and path-loss exponent is derived. It is found that targeted-receiver CSI, which can be acquired with low overhead in duplex systems …
A Physical Model For The Kink Effect In Inalas/Ingaas Hemt’S, Mark Somerville, Alexander Ernst, Jesus Del Alamo
A Physical Model For The Kink Effect In Inalas/Ingaas Hemt’S, Mark Somerville, Alexander Ernst, Jesus Del Alamo
Mark Somerville
We present a new model for the the kink effect in InAlAs/InGaAs HEMTs. The model suggests that the kink is due to a threshold voltage shift which arises from a hole pile-up in the extrinsic source and an ensuing charging ofthe surface and/or the buffer-substrate interface. The model captures many of the observed behaviors of the kink, including the kink's dependence on bias, time, temperature, illumination, and device structure. Using the model, we have developed a simple equivalent circuit, which reproduced well the kink's dc characteristics, its time evolution in the nanosecond range, and its dependence on illumination.
Determining Dominant Breakdown Mechanisms In Inp Hemts, Mark Somerville, Chris Putnam, Jesus Del Alamo
Determining Dominant Breakdown Mechanisms In Inp Hemts, Mark Somerville, Chris Putnam, Jesus Del Alamo
Mark Somerville
We present a new technique for determining the dominant breakdown mechanism in InAlAs-InGaAs high-electron mobility transistors. By exploiting both the temperature dependence and the bias dependence of different physical mechanisms, we are able to discriminate impact ionization gate current from tunneling and thermionic field emission gate current in these devices. Our results suggest that the doping level of the supply layers plays a key role in determining the relative importance of these two effects.
Strained Si On Insulator Technology: From Materials To Devices, T. Langdo, M. Currie, Z.-Y. Cheng, J. Fiorenza, M. Erdtmann, G. Braithwaite, C. Leitz, C. Vineis, J. Carlin, A. Lochtefeld, M. Bulsara, Isaac Lauer, Dimitri Antoniadis, Mark Somerville
Strained Si On Insulator Technology: From Materials To Devices, T. Langdo, M. Currie, Z.-Y. Cheng, J. Fiorenza, M. Erdtmann, G. Braithwaite, C. Leitz, C. Vineis, J. Carlin, A. Lochtefeld, M. Bulsara, Isaac Lauer, Dimitri Antoniadis, Mark Somerville
Mark Somerville
SiGe-free strained Si on insulator (SSOI) is a new material system that combines the carrier transport advantages of strained Si with the reduced capacitance and improved scalability of thin film silicon on insulator (SOI). We demonstrate fabrication of 20% Ge equivalent strain level SSOI substrates with Si thicknesses of 100 and 400 Å by hydrogen-induced layer transfer of strained Si layers from high quality graded SiGe virtual substrates. The substrate properties are excellent: wafer scale strained Si film thickness uniformities are better than 8%, strained Si surface roughnesses are better than 0.5 nm RMS, and robust tensile strain levels are …
An Autozeroing Floating-Gate Amplifier, Paul Hasler, Bradley Minch, Chris Diorio
An Autozeroing Floating-Gate Amplifier, Paul Hasler, Bradley Minch, Chris Diorio
Bradley Minch
We have developed a bandpass floating-gate amplifier that uses tunneling and pFET hot-electron injection to set its dc operating point adaptively. Because the hot-electron injection is an inherent part of the pFET's behavior, we obtain this adaptation with no additional circuitry. Because the gate currents are small, the circuit exhibits a high-pass characteristic with a cutoff frequency less than 1 Hz. The high-frequency cutoff is controlled electronically, as is done in continuous-time filters. We have derived analytical models that completely characterize the amplifier and that are in good agreement with experimental data for a wide range of operating conditions and …
Multiple-Input Translinear Element Networks, Bradley Minch, Paul Hasler, Chris Diorio
Multiple-Input Translinear Element Networks, Bradley Minch, Paul Hasler, Chris Diorio
Bradley Minch
We describe a new class of translinear circuits that accurately embody product-of-power-law relationships in the current signal domain. We call such circuits multiple-input translinear element (MITE) networks. A MITE is a circuit element, which we defined recently that produces an output current that is exponential in a weighted sum of its input voltages. We describe intuitively the basic operation of MITE networks and provide a systematic matrix technique for analyzing the nonlinear relationships implemented by any given circuit. We also show experimental data from three MITE networks that were fabricated in a 1.2-μm double-poly CMOS process.
A Second-Order Section Built From Autozeroing Floating-Gate Amplifiers, Paul Hasler, Theron Stanford, Bradley Minch
A Second-Order Section Built From Autozeroing Floating-Gate Amplifiers, Paul Hasler, Theron Stanford, Bradley Minch
Bradley Minch
We introduce the autozeroing floating-gate (AFGA) secondorder section. We built this second-order filter where the corner frequency and Q are electronically tunable based on a classic filter topology and principles of operational transconductance amplifiers. We built this second order filter using three AFGAs—our floating-gate amplifier that sets its operating point by the interaction of hot-electron injection and electron tunneling.
Single-Event Charge Enhancement In Soi Devices, David Kerns, Sherra Kerns, L Massengill, M Alles
Single-Event Charge Enhancement In Soi Devices, David Kerns, Sherra Kerns, L Massengill, M Alles
Sherra E. Kerns
Studies are presented of single-particle ion effects in body-tied CMOS/silicon-on-insulator (SOI) devices. It is shown that two mechanisms can contribute to SOI soft-error rates: a direct ion-induced photocurrent and a local lateral bipolar current. The total amount of charge collected is sensitive to the relative locations of the ion strike and the body-to-source tie.
Single-Event Charge Enhancement In Soi Devices, David Kerns, Sherra Kerns, L Massengill, M Alles
Single-Event Charge Enhancement In Soi Devices, David Kerns, Sherra Kerns, L Massengill, M Alles
David V. Kerns
Studies are presented of single-particle ion effects in body-tied CMOS/silicon-on-insulator (SOI) devices. It is shown that two mechanisms can contribute to SOI soft-error rates: a direct ion-induced photocurrent and a local lateral bipolar current. The total amount of charge collected is sensitive to the relative locations of the ion strike and the body-to-source tie.