Superior Linearity Research Articles

A 5 GHz 0.95 dB NF Highly Linear Cascode Floating-Body LNA in 180 nm SOI CMOS Technology

A 5 GHz CMOS LNA featuring a record 0.95 dB noise-figure is reported. Using an inductively-degenerated cascode topology combined with floating-body transistors and high-Q passives on an SOI substrate, record noise figure and superior linearity performance at 5 GHz are obtained. The low-noise amplifier (LNA) achieves up to 11 dB of gain while consuming 12 mW dc power, and is capable of supporting 802.11a WLAN applications. The impact of SOI body-contact on the LNA RF performance is described and linked to improved intermodulation performance.

A single serum dilution enzyme-linked immunosorbent assay for determining anti-human papillomavirus (HPV) antibody titres in humans immunised with prophylactic HPV vaccines

Two types of prophylactic human papillomavirus (HPV) vaccines are currently available. However, there is no simple monitoring system for assessing acquired immunity that can cope simultaneously with large numbers of serum samples. Approximately 30% of women with normal cytology are known to be seropositive for HPV types 16 and 18 because of the high prevalence of these HPV types. Therefore, to be useful the monitoring system has to discriminate clearly between vaccine recipients and other serology groups. However, there has never been any focus on developing a method to satisfy this condition. In this study, we developed a high-throughput single-serum-dilution enzyme-linked immunoassay (ELISA) system for determining anti-HPV antibody titres following vaccination. We optimised the conditions for each ELISA step to increase its accuracy and precision and to avoid the high background of non-specific reactions that is a major problem for serology assays. The new ELISA system has superior linearity, accuracy and reproducibility. Moreover, it clearly discriminated between antibody levels in vaccine recipients and those in other serology groups such as individuals with normal cervical cytology and those with cervical cancer. Therefore, this single-serum-dilution ELISA should be very useful for assessing the acquired immunity of HPV vaccine recipients.

Preparation, properties and application research of piezoelectric traffic sensors

With increasingly development of traffic construction, development of intelligent traffic sensors has great significance for dynamic monitoring of traffic vehicles. In this research, cement based piezoelectric intelligent traffic sensors were prepared by using PZT piezoelectric ceramic as the sensing element and the mixture of cement and epoxy resin as packaging material, and the linear property, sensitivity, repeating ability and pulse response ability of the sensors were also tested. The results show that sensors have superior pulse response property, high linearity and sensitivity under pulse loading, besides it has also good repeating ability under cycling loading. The traffic flow and traffic velocity were monitored by using the piezoelectric traffic sensors in a testing road. The research shows that the designed piezoelectric traffic sensors can monitor effectively the amount of passerby who pass through the testing road, and that the vehicle velocity can also be obtained accurately according to the pulse response interval of piezoelectric traffic sensors.

6D direct-drive technology for planar motion stages

Achieving 6D direct drive motion control over long planar strokes on a single mover can greatly improve machine performance. Existing solutions are either limited to small-stroke applications (a fraction of the stage size) or require a large number of coils with enormous control complexity. This paper presents a novel 6D direct drive technology for planar stages with many advantages: (1) stroke can be on the order of several meters; (2) the number of coils increases linearly with motion range; (3) no end effects or force coupling between axes; and (4) ease of control and superior force linearity.

Parallel-Plate MEMS Variable Capacitor With Superior Linearity and Large Tuning Ratio Using a Levering Structure

An innovative and simple method is proposed to achieve ultralinear behavior in a capacitance-versus-voltage response and to obtain a large capacitance tuning ratio in a parallel-plate microelectromechanical systems (MEMS) variable capacitor by moving the plate to an increasing-gap direction. By adopting a levering structure, the common closing-gap motion of the electrostatic actuator was transformed into an increasing-gap movement in order to decrease the capacitance as the actuation voltage was increased. By balancing out the rate that the plate moves up as the actuation voltage increased and the rate that the capacitance decreases as the plate moves up, high linearity was achieved. The proposed MEMS variable capacitor, which was fabricated via metal surface micromachining, showed an excellent linearity factor (LF) of 99.5% in the C-V response, and a capacitance tuning ratio of 134% was achieved in the actual usage range (10-45 V) at a low frequency. When it was operated at 1 GHz, the proposed device demonstrated an LF of 99.5% and a capacitance tuning ratio of 125%.

Coomassie Staining as Loading Control in Western Blot Analysis

In Western blotting, immunodetection of housekeeping proteins is routinely performed to detect differences in electrophoresis loading. The present work describes a much faster and simpler protein staining method, which is compatible with ordinary blocking conditions. In addition, the method can be used after immunodetection with superior linearity compared to ordinary staining methods. After immunoblotting and staining, protein bands can be further identified using peptide mass fingerprinting.

Experimental Verification of Design Techniques of Permanent-Magnet Synchronous Motors for Low-Torque-Ripple Applications

High-performance motor drive applications require smooth operation with minimum torque ripple. This paper is focused on identifying various design parameters in the stator and rotor that can be utilized to reduce the torque ripple of sinusoidally excited permanent-magnet synchronous motors. This paper investigates the sensitivity of various design parameters on torque ripple and torque linearity that must be considered at the design stage for low-torque-ripple applications. Only the torque ripple and torque nonlinearity due to electromagnetic origin are considered in this paper. Finite-element analysis along with experimental data is provided to validate the findings. Design techniques have been provided to minimize the overall torque ripple and increase the torque linearity. Tradeoff between magnetic flux per pole and electrical loading of the machine is needed for low-torque-ripple performance. This also provides superior torque linearity.

A Flash A/D Converter Using Complementarily Combined SQUIDs

We propose a new design of a superconductive flash analog-to-digital (A/D) converter circuit with improved linearity. This circuit is composed of the equivalent of two quasi-one-junction SQUIDs (QOSs) that are connected at the comparator. The analog signal is input to the front end of each of the QOSs complementarily, with opposite polarity for each. Though the mechanism of the quantization in each QOS is basically the same as that in conventional ones, the mixed quantized output shows comparatively superior linearity. Moreover, unintended offsets due to <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> delays are completely canceled in this circuit, suppressing dynamic distortions in the comparator even without a feedback loop for compensation. This makes the circuit free from bandwidth limitation related to the time constant in the loop. We have carried out a computer simulation for A/D converter operation of the circuit and showed a sampling ability of 150 GS/s when the critical current density ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> ) is 40 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Functional test results of the circuits are also reported.

The nanogap Pirani—a pressure sensor with superior linearity in an atmospheric pressure range

We have designed and fabricated a surface micromachined Pirani pressure sensor with an extremely narrow gap between its heater and heatsink (substrate) with superior output linearity in the atmospheric pressure range. The gap size of the device has been reduced to 50 nm by using a layer of PECVD amorphous silicon as a sacrificial layer and a xenon difluoride (XeF2) gas phase etching technique. Such a narrow gap pushes the transition from molecular to continuum heat conduction to pressures beyond 200 kPa. The higher transition pressure increases the measurement range and sensitivity of the gauge in atmospheric pressures. The gas phase etching of the sacrificial layer eliminates stiction problems related to a wet etching process. The active area of the sensor is only a 6 × 50 µm2 microbridge anchored to the substrate at both ends. An innovative fabrication technique was developed which resulted in a virtually flat microbridge with improved mechanical robustness. This process enabled us to have a very well-controlled gap between the microbridge and the substrate. The device was tested in a constant heater temperature mode with pressure ranges from 0.1 to 720 kPa. The heater power was only 3 mW at 101 kPa (atmospheric pressure), which increased to about 8 mW at 720 kPa. The output sensitivity and nonlinearity of the device were 0.55% per kPa at 101 kPa and ±13% of the output full scale, respectively.

Study of hot electrons generated from intense laser-plasma interaction employing Image Plate

Image Plate (IP) is convenient to be used and very suitable for radiation detection because of its advantages such as wide dynamic range, high detective quantum efficiency, ultrahigh sensitivity and superior linearity. The function mechanism and characteristics of IP are introduced in this paper. IP was employed in the study of hot electrons generated from intense laser-plasma interaction. The angular distribution and energy spectrum of hot electrons were measured with IP in the experiments. The results demonstrate that IP is an effective radiation detector for the study of laser-plasma interaction.

Enabling Low-Distortion Varactors for Adaptive Transmitters

A varactor diode configuration is presented for the implementation of low-distortion tunable matching networks, phase shifters, and filters. The configuration is based on varactors with an "exponential" C(V) relation in antiseries configuration with specific control voltage harmonic loading conditions. The resulting network combines a high capacitance tuning range with relatively low control voltages and excellent linearity. The linearity is independent of the applied control voltage and does not degrade at low tone spacing, which is ideal for the realization of adaptive transmitters and modulators. A specific N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</sub> x-2 varactor doping profile is required for exact third-order intermodulation (IM3) cancellation. The remaining distortion is dominated by the much smaller fifth-order nonlinearities. The required impedance levels of the harmonic terminations are studied in terms of the maximum modulation bandwidth for which the proposed configuration remains linear. The doping profile optimization for quality factor, tuning range, and breakdown voltage is discussed. For experimental verification, the proposed varactor configuration has been implemented using a silicon-on-glass technology. The measurements demonstrate IM3 cancellation and indicate a superior linearity for modulated signals up to 10-MHz bandwidth.

Multilayered LiNbO 3 actuator for XY-stage using a shear piezoelectric effect

LiNbO 3 piezoelectric single crystal is expected to have a superior linearity and non-hysteresis. We have already demonstrated these distinguished piezoelectric performances using a Z-stage type LiNbO 3 multilayered actuator. In this study, a XY-stage type actuator was fabricated. By optimizing the cutting angle (163° Y-cut), the shear piezoelectric constant becomes as large as 66 pC/N, and the multilayered structure enables larger piezoelectric displacement and the effective piezoelectric coefficient becomes compatible to PZT. To realize the ultra-high precise positioning system, a multilayered LiNbO 3 actuator (multilayered number 10) was fabricated to examine the piezoelectric vibration and its linearity. By investigating the relationship between applied voltage and the piezoelectric displacement, it was confirmed that this actuator has excellent linearity and non-hysteresis. The effective piezoelectric constant was calculated to 660 pC/N and obtained maximum displacement was 64.5 nm with 100 V, corresponding to 645 pC/N.

Stain efficiency and MALDI-TOF MS compatibility of seven visible staining procedures

Visible stain is still the most popular protein staining method used in proteomic approaches. However, most published data have been derived from comparisons between visible dyes and fluorescent dyes. In this work, we have focused on seven widely used visible staining procedures--Neuhoff CCB, blue silver, and five silver stains (LKB SN, He SN, Yan SN, Vorum SN, and Blum SN)--and studied their stain efficiencies and MALDI-TOF MS compatibilities on 1-D and 2-D PAGE. It was concluded that blue silver is slightly better in terms of stain efficiency than Neuhoff CCB, but it presented worse MS compatibility. Neuhoff CCB presented better MS compatibility and superior linearity but worse sensitivity than silver stains. Among the five silvering procedures, He SN showed the best MS compatibility and a reasonable staining efficiency; Yan SN lowered the chances of obtaining the protein identity by PMF but gave the best stain efficiency; Vorum SN gave a very clear background and a great contrast, while Blum SN was the worst in this respect. The implications of these results for the selection of a convenient stain are discussed according to specific objectives as well as practical aspects.

High-Performance Planar Isolated Current Sensor for Power Electronics Applications

A planar current sensor, comprised of a magnetic current transformer and a hall-effect element, is presented. The sensor has a broad frequency bandwidth from dc up to 30 MHz, a high current rating (40-A dc), superior linearity, high EMI immunity, small size, robustness, and low realization cost. The main design formulations are given analytically; simulations and finite-element results are presented for verification. Experimental results of current step response and dv/dt immunity are included.

SU-EE-A2-06: Using Multi-Element Detector Arrays for Commissioning Active Wobbling and Energy-Stacking Proton Beams

Multi-element detector arrays were constructed to characterize the properties of active wobbling and energy-stacking proton beam commissioning. A multi-layer ionization chamber (MLIC) array measured depth doses, and a multi-pad ionization chamber (MPIC) array measured lateral profiles. The MLIC consists of 122 chambers with 1.82mm spatial resolution and has an effective physical density about 60% that of water. The MPIC consists of 128 chambers arranged in two 38cm long orthogonal lines with spatial resolution of 5mm within 10cm radius and 7mm outwardly. During performance tests on the MLIC and MPIC, good collection efficiency with superior reproducibility and linearity were achieved. The relative variation on the sensitivity for each individual chamber was carefully calibrated before use for proton beam characterization. The relatively small charge collection area (6mm in diameter) and volume (0.3 cm3) of each chamber has a well guarded lead and allows one to study the effect of field size on depth dose distributions for fields of approximately 2 cm to 10 cm in diameter. The MLIC is calibrated using a pristine proton beam with range 27cm in water. To calibrate the large dimensional MPIC, uniform lateral dose distributions in water within 1% were generated. Analytical functions were applied to fit measured depth dose and lateral distributions in water during the calibrations. With proper calibrations, the uncertainties of measured depth doses and lateral profiles with these multi-element detector arrays were within 1% with respect to ones measured point by point with an ion chamber in a water phantom. Significant time savings for beam measurements were thus achieved.

Comparative Studies on Double δ -Doped Al0.3Ga0.7As ∕ InxGa1 − xAs ∕ GaAs Symmetrically Graded Doped-Channel Field-Effect Transistors

This work provides comparative studies of a double δ-doped symmetrically graded doped-channel field-effect transistor (DD-DCFET) with respect to a conventional double δ-doped pseudomorphic high electron mobility transistor (pHEMT) and a conventional DCFET structure. All threes samples, grown by the low-pressure metallorganic chemical vapor deposition (LP-MOCVD) system, have identical layer structures except for their different doping schemes. Comprehensive investigations on the static, microwave, and temperature-dependent characteristics have been made. Possessing the advantages of DCFETs and pHEMTs, the proposed DD-DCFET has demonstrated comprehensively superior linearity, current drive, voltage gain, high-frequency characteristics, and thermal stability characteristics. It is promisingly suitable for millimeter-wave integrated circuit applications.

Non-hysteresis and perfect linear piezoelectric performance of a multilayered lithium niobate actuator

A LiNbO3 piezoelectric single crystal is expected to have superior linearity and non-hysteresis in piezoelectric performance. By optimizing the cutting angle (36°Y-cut), the thickness of the piezoelectric constant becomes as large as 38pC/N, and a multilayered structure enables the piezoelectric displacement to become larger. The effective piezoelectric coefficient becomes comparable to that of a PZT actuator. To realize an ultra-high precise positioning system, a multilayered LiNbO3 actuator was fabricated to examine the piezoelectric vibration characteristic and linearity. By investigating the relationship between applied voltage and the piezoelectric displacement, it was confirmed that this actuator had superior linearity and non-hysteresis performance. The effective piezoelectric constant was measured at 380pC/N, and the maximum displacement at 700V was more than 250nm.

Analysis of 18F-labelled synthesis products on TLC plates: Comparison of radioactivity scanning, film autoradiography, and a phosphoimaging technique

We compared radioactivity scanning, film autoradiography, and digital photostimulated luminescence (PSL) autoradiography (phosphoimaging technique) in detection of radioactivity on thin-layer chromatography (TLC) plates. TLC combined with radioactivity detection is rapid, simple, and relatively flexible. Here, 18F-labelled synthesis products were analyzed by TLC and the radioactivity distribution on the plates determined using the three techniques. Radioactivity scanning is appropriate only with good chromatographic resolution and previously validated scanning parameters. Film autoradiography exhibits poor linearity if radioactivity varies greatly. PSL provides high sensitivity and resolution and superior linearity compared with the other methods.

High-temperature threshold characteristics of a symmetrically graded InAlAs∕InxGa1−xAs∕GaAs metamorphic high electron mobility transistor

High-temperature threshold characteristics of a symmetrically graded δ-doped InAlAs∕InxGa1−xAs∕GaAs (x=0.5→0.65→0.5) metamorphic high electron mobility transistor (MHEMT) have been investigated. The thermal threshold coefficients, defined as ∂Vth∕∂T, are superiorly low at 0.9mV∕K from 300to420K and at −0.75mV∕K from 420to500K. An interesting polarity change of the thermal threshold coefficient was observed around 420K due to the variation of thermal modulation effects. The present MHEMT device, with stabilized thermal threshold variations and superior high-temperature linearity characteristics, is promising for high-temperature circuit applications.

A capacitor cross-coupled common-gate low-noise amplifier

The conventional common-gate low-noise amplifier (CGLNA) exhibits a relatively high noise figure (NF) at low operating frequencies relative to the MOSFET f/sub T/, which has limited its adoption notwithstanding its superior linearity, input matching, and stability compared to the inductively degenerated common-source LNA (CSLNA). A capacitor cross-coupled g/sub m/-boosting scheme is described that improves the NF and retains the advantages of the CGLNA topology. The technique also enables a significant reduction in current consumption. A fully integrated capacitor cross-coupled CGLNA implemented in 180-nm CMOS validates the g/sub m/-boosting technique. It achieves a measured NF of 3.0 dB at 6.0 GHz and consumes only 3.6 mA from 1.8 V; the measured input-referred third-order intercept ( IIP3) value is 11.4 dBm. The capacitor cross-coupled g/sub m/-boosted CGLNA is attractive for low-power fully integrated applications in fine-line CMOS technologies.