Smart sensor interface with A/D conversion and programmablecalibration

In this paper we present a new architecture for a smart sensor interface. It is based on an oversampled A/D converter associated with a small ROM containing calibration coefficients. The nonlinear function desired is obtained by piecewise linear interpolation between the values stored in the ROM, without any additional circuits. This solution has the advantage of high programming flexibility, long-term stability, and low area consumption. Moreover, it is suitable for co-integration with sensors because of its minimum analog content. A prototype was integrated in a CMOS 1.2-μm technology. Simulation and experimental results are reported together with a detailed theoretical analysis and some design guidelines     

A 150 MHz 0.6 μm BiCMOS superscalar microprocessor

An implementation of the Pentium microprocessor architecture in 0.6 μm BiCMOS technology is described. Power dissipation is reduced and performance is enhanced over the previous generation. Processor features, implementation technology, and circuit techniques are discussed. An internal clock rate of 150 MHz is achieved at 3.7 V and -55°C     

Ground-based remote profiling in atmospheric studies: an overview

Over the last 25 years, ground-based remote profiling has found increasing applications in atmospheric studies where its high vertical and temporal resolution and extended vertical coverage are giving scientists a clearer understanding of atmospheric processes in the troposphere. The authors describe the current status of techniques for vertical profiling of mean wind speeds, temperature, and humidity, and discuss options for combining them     

Degrees and diversity at work

A study of of over 3000 engineers and scientists employed in the United States explored the interplay of levels of education with gender and native versus immigrant status. The results suggest that some of these R&D professionals may be underutilised and perhaps less effective than they could be     

Achievement of pencil-beam radiation from a TM01 modecircular waveguide source

A method employing appropriately placed parallel-metallic plates in the aperture of a TM₀₁ mode circular waveguide source so as to have it produce pencil-beam radiation is described and analyzed. Programmed computations, with experimental verification, are given for the case of a C-Band TM₀₁ source flared out to a conical horn so as to produce moderate (22 dBi) gain. Means of extending the method to achieve higher gains (40 dBi to 60 dBi) and to modify the plate arrangement so as to produce the same effect with a TE₀₁ mode are briefly outlined     

Mutual impedance between skewed patch antennas

This paper considers the mutual impedance between skewed rectangular microstrip patch antennas as a function of the skew angle. The analysis is done using the exact Green's function for the patch and the method of moments to solve for the field. The theoretical results obtained are compared with published experimental results     

Excess noise in AlGaAs/GaAs heterojunction bipolar transistors andassociated TLM test structures

Noise measurements both on transmission line model (TLM) test structures and on associated HBT's are presented. Contact noise is proved to be negligible in the TLM's related to the base structure of transistors. A Hooge parameter for p⁺⁺ doped GaAs is extracted. Activation energies are calculated from results versus temperature. Considering the TLM related to the structure of the emitter, it is shown that the g-r levels observed originate from the AlGaAs layer. Noise measurements on HBT's also exhibit excess noise. A value of the cutoff frequency between the equivalent input current white noise and the 1/f component is given. The base current dependencies associated with different measurement configurations suggest the 1/f noise to come from the base or the emitter-base junction. The g-r components are studied as a function of temperature. Activation energies are deduced. Finally a comparison of the TLM and HBT noise results is presented. The presence of the complex DX center and of g-r levels in the base region are proposed as possible origins for the g-r noise in HBT's     

Analysis of the latch and breakdown phenomena in N and P channelthin film SOI MOSFET's as a function of temperature

A study of the latch and breakdown phenomena in thin film N- and P-channel SOI MOSFET's is performed as a function of temperature. For P-type MOSFET's, for which no investigation of the parasitic bipolar transistor has been carried out, we show that latch problems are observed in the subhalf-micrometer range, while this feature is emphasized in the micrometer range for N-channel transistors. In addition, it is demonstrated by theoretical considerations and experimental results that these parasitic effects are strongly reduced at liquid nitrogen temperature and vanish almost entirely at liquid helium temperature. Similar improvements are obtained at low temperature in both N and P-channel SIMOX MOSFET's     

Drain structure optimization for highly reliable deep submicrometern-channel MOSFET

A guideline for n^- fully gate overlapped (FOLD) structure design optimization has been studied. From the viewpoint of reliability, the greatest reduction in substrate current directly leads to the most reliable n^- design for the FOLD structure. The current path modulation phenomenon due to the trapped charge at the n ^- extension region dominates the hot-carrier induced characteristics change for conventional lightly doped drain (LDD) structure with side-wall spacer. This phenomenon is minimized in the FOLD structure due to its higher controllability of the gate electrode than the LDD structure at the n^- extension region. Furthermore, it was also confirmed that the 0.3 μm optimized FOLD structure can achieve high circuit performance at 3.3 V operation, maintaining hot-carrier resistance     

A microwave Gaussian-beam launcher with an active aperture-blockageto control the spot-size of the beam

A method of controlling the spot-size of a focused microwave Gaussian-beam using an active aperture-blockage is described. The Gaussian-beam launcher consists of an open-ended scalar-horn with a dielectric hyperhemisphere at its aperture. Also included is an AgI-pellet at the aperture-center with a provision to heat it with an external dc source. The scalar-horn plus the dielectric lens launch a Gaussian-beam; and, the AgI pellet when heated, becomes a superionic conductor offering an aperture-blockage. This results in a variation of the spot-size of the emergent-beam. Theoretical results and experimental data are furnished and compared