Accurate measurement of millimeter-wave attenuation from 75 GHz to 110 GHz using a dual-channel heterodyne receiver

A dual-channel millimeter-wave attenuation measurement system from 75 GHz to 110 GHz using a heterodyne receiver is described. The millimeter-wave attenuation is derived from the voltage ratio at 5.02 kHz using an inductive voltage divider as a reference standard. The measurement uncertainties are estimated to be 0.015–0.030 dB for attenuation ranging from 0 dB to 70 dB at 110 GHz. Measurement results of a waveguide rotary vane attenuator with 0–70 dB attenuation steps at 110 GHz are presented.     

Inductorless Ultra-Wide Band Front-End Chip Design with Noise Cancellation Technology for Wireless Communication Applications 10

An inductorless Ultra-Wide Band(UWB)receiver front-end chip design used in wireless communications for the frequency band of 3.1～4.8 GHz is presented.This homodyne receiver mainly consists of a differential Low Noise Amplifier(LNA)circuit followed by a down-converting mixer.The proposed LNA circuit with a noise canceling resistor is connected to the CMOS device's body to reduce the substrate thermal noise.Simulation and measurement results show that the chip can reduce the front-end Noise Figure(NF)about 0.5dB and achieve the Conversion Gain(CG)of 19.44～21.57 dB and double-sideband NF less than 7.8 dB.Also,the input third-order intercept point(IIP3)is-11 dBm,and the input second-order intercept point(IIP2)is 49 dBm.Fabricated in TSMC 0.18 μm CMOS technology,this chip occupies only 0.167 mm2 and dissipates power 59.2 mW.     

Accelerated nano-fretting testing of Si(1 0 0)

A nano-fretting test technique has been recently developed to enable the in situ study of wear at the micro- and nano-scale. It has been used to study the small scale wear of Si(1 0 0) using a 4.6 μm spheroconical indenter as test probe over the applied load range 30-300 mN. Contact damage assessment by in situ measurements of probe displacement were supplemented by post-test SEM imaging and wear scar analysis by confocal microscopy. The wear behaviour was dependent on the rate of initial loading. When the load was applied abruptly (<0.3 s), radial and lateral cracking and material removal was observed and large displacement jumps (pop-ins) were observed during the subsequent 1000 s constant load nano-fretting test. The crack morphology was very similar to that in repetitive nano-impact tests and conventional nanoindentation at higher applied load with the same probe. In contrast, when the load was applied more slowly (10 s) radial cracking was not observed and there was a distinct threshold load (∼100 mN) marking the transition to a more severe wear mode with extensive lateral cracking and material removal.     

RF CMOS transceiver at 2.4 GHz in wearables for measuring the cardio-respiratory function

This paper presents a radio-frequency (RF) transceiver for operation in the 2.4 GHz ISM band. The RF CMOS transceiver can be supplied with only 1.8 V, and it was designed to establish wireless links for distances up to 10 m, for a maximum baud-rate of 250 Kbps with a Bit Error Probability less than 10⁻⁶. The transmitter can deliver a output power of 0 dBm with a consumption of only 11.2 mW, while the receiver has sensitivity of −60 dBm and consumes only 6.3 mW. The goal of RF CMOS transceiver is for co-integration with sensors in the same die using microsystems techniques. The target application of such microsystems is in wearables (e.g., in wireless electronic shirts) for measuring biomedical data of patients. The wireless electronic shirt (WES) measures the heart rate and the respiratory frequency, and at the same time it allows patients to maintain their mobility.     

Noise characteristics of high-frequency,short-duration GPS records from analysis of identical,collocated instruments

High-rate (>1 Hz) GPS, currently used for measurement of dynamic processes and as a universal time and frequency standard, is usually assumed to be affected by site-specific errors and only limited studies of the error properties of high-frequency (10 Hz), short-duration (<100 s) GPS records exist. Preliminary studies, provided evidence of instrument-specific errors, which were investigated on the basis of systematic experiments with various types of stationary, collocated, identical GPS units. This analysis revealed differences between couples of receiver/antenna units, while spectral analyses revealed low-frequency colored noise, statistically significant below 0.2 Hz and, gradually decaying with increasing duration of observations, so that above 2.5 Hz measurements are contaminated only by white noise.     

Uncertainty analysis for a phase-detector based phase noise measurement system

Phase noise is an important parameter to characterise the frequency stability of oscillators and synthesised signal generators. Accurate measurement of phase noise is required for various applications in radar, communication and navigation systems. A single-channel phase-detector based phase noise measurement system is described. The system’s measurement errors and uncertainties have been analysed in details. The expanded uncertainty is about 2.7 dB for calibrating phase noise of a signal generator at 0.001–1.6 GHz for frequency offsets from 1 Hz to 100 kHz. The uncertainty budget for measuring a signal generator’s phase noise at 640 MHz is also presented.     

A novel approach for realization of primary vibration calibration standard by homodyne laser interferometer in frequency range of 0.1 Hz to 20 kHz

The paper discusses the primary vibration calibration standard of NPL, India capable of calibrating the reference accelerometers in frequency range from 0.1 Hz to 20 kHz as per ISO 16063-11. The excitation subsystem produces constant vibration at a specified amplitude and frequency, while the measurement system uses NI interface for measuring the quadrature output. The acceleration level and voltage level at the calibration frequency f is determined by applying a Discrete Fourier Transform to the voltage and displacement signals, and then examining the spectral component at frequency f. A PC-based data acquisition system acquires the accelerometer voltage signal and analog quadrature interferometer photodetector signal pair as well as a digital quadrature pair whereby the software processes the demodulated photodetector signals to reconstruct the armature displacement. The validation of the calibration results for standard reference accelerometers with manufacturer results and uncertainty in calibration in entire frequency range 0.1 Hz to 20 kHz is reported in the present work.     

Investigation of some dielectric properties of phosphate glasses doped with iron oxides,by a microwave technique

The effects of iron ions on dielectric properties of lithium sodium phosphate glasses were studied by non-usual, fast and non-destructive microwave techniques. The dielectric constant (ε′), insertion loss (L) and microwave absorption spectra (microwave response) of the selected glass system xFe₂O₃·(1 − x)(50P₂O₅·25Li₂O·25Na₂O), being x = 0, 3, 6, … , 15 expressed in mol.%, were investigated. The dielectric constant of the samples was investigated at 9.00 GHz using the shorted-line method (SLM) giving the minimum value of ε′ = 2.10 ± 0.02 at room temperature, and increasing further with x, following a given law. It was observed a gradual increasing slope of ε′ in the temperature range of 25 ? t ? 330 °C, at the frequency of 9.00 GHz. Insertion loss (measured at 9.00 GHz) and measurements of microwave energy attenuation, at frequencies ranging from 8.00 to 12.00 GHz were also studied as a function of iron content in the glass samples.     

MoS2(0 0 0 1)/MoO3(0 1 0)/MoS2(0 0 0 1) friction-reducing system

A system of MoO₃(0 1 0) nanocrystals confined between MoS₂(0 0 0 1) surfaces is reported. MoO₃(0 1 0) nanocrystals act as friction-reducing materials between MoS₂(0 0 0 1) surfaces, where the frictional coefficient is an extremely small value of 0.005. This lubricated system is very promising for use in movable parts of nano- and micromachines because it works under ambient conditions.     

Microwave cavity technique to study the dielectric response in 4′-n-Heptyl-4-biphenyl nematic liquid crystal at 20.900 GHz and 29.867 GHz

The experimental studies of the dielectric response in liquid crystal at different temperatures have been done by using a microwave cavity spectrometer. The Microwave Cavity Spectrometer has been used to measure and compare the relative shift, width and amplitude of the resonance profile for the sample loaded in the cavity operated in TM₀₁₀ mode at two different frequencies 20.900 GHz and 29.867 GHz. The comparative study of dielectric loss, and relaxation time of above liquid crystal at different frequencies has also been done at different temperatures. The method is used for its inherent accuracy and requirement of minute quantity of sample. Importance of nematic liquid crystal for infiltrating photonic crystal fibers for modification of their properties is indicated.     

Complex permittivity measurement using capacitance method from 300 kHz to 50 MHz

Complex permittivity measurement has been performed using a parallel plate capacitor and a vector network analyzer (VNA) from 300 kHz to 50 MHz. The material under test (MUT) is a flat and thin sample clamped between the capacitor plates and connected to the VNA to obtain its two port S parameters. The S parameter is converted into impedance to calculate the complex permittivity using Matlab program. Techniques used to overcome the air gap and stray capacitance was described. Measurement obtained using the proposed method was compared with the free space method to validate its accuracy. The percent difference is less than 5%.     

Evaluation of actual sensitivity limit in a 10 N·m dead weight torque standard machine and stability of a new 1 N·m torque transducer

A 10 N·m dead weight torque standard machine (10-N·m-DWTSM) has been under development at NMIJ/AIST since 2006 to expand the range of the torque standard. Estimation of the sensitivity limit of the fulcrum is one of the most important issues to realize a precise reference torque of small capacity by using a dead weight torque standard machine. In this study, a torque transducer was installed on the 10-N·m-DWTSM in order to keep the moment-arm on the horizontal line (balancing). The sensitivity limit of the fulcrum under real calibration conditions was estimated by reading the change in the output from the torque measuring device (TMD: the torque transducer with a cable and an indicating device) when small weights were loaded or unloaded. The small weights used in the experiment were 0.5 mg, 1 mg, 10 mg, and 100 mg. Equivalent radial loads from 0.1 N·m to 10 N·m were imposed on the fulcrum during the sensitivity measurement.     

NMC–NMIJ bilateral comparison of millimeter-wave attenuation in WR-15 waveguide band at 50 GHz and 54 GHz

This paper reports on a bilateral comparison of millimeter-wave attenuation in WR-15 waveguide band between the National Metrology Institute of Japan (NMIJ) and the National Metrology Centre, A1STAR (NMC). Different types of attenuation measurement systems were independently developed at both laboratories. The systems are based on a stabilized single-channel intermediate frequency (IF) substitution method at NMIJ, and a dual-channel audio frequency substitution method at NMC. A comparison was carried out at 50 GHz and 54 GHz using a programmable step attenuator fitted with precision coaxial to waveguide adaptors as a traveling standard. Good agreement of the measurement results between both laboratories was verified in the attenuation range up to 60 dB.     

Analysis of pressure distribution for the various gas flow vacuum system in the range from 1 Pa to 133 Pa

The measurement and control of gas flow are critical in many manufacturing processes. Semiconductor manufacturers, in particular, require a number of different process gases for etching, deposition, oxidation, doping and inerting applications. In many of these, as well as other industrial and research processes including measurement of partial pressures with residual gas analyzers (RGAs), calibration of vacuum gauges, and conductance of a conductance-reducer , accurate measurement and stability of the gas pressure within the reaction vacuum chamber is essential. In the present work, pressure distribution in the chamber of a newly developed flow control system was investigated for three gases (Ar, N₂, and He) range from 1 Pa to 133 Pa. For all the gases, the relative deviations in pressure distribution near the gas inlet and outlet were in the range of −1.3% and 1.2% respectively.     

Spin polarization of field-emitted electrons from half-metallic Co2MnSi thin films grown on a W(0 0 1) facet

We measured spin polarization of electrons field-emitted from half-metallic Co₂MnSi thin film grown on a W(0 0 1) facet via chromium buffer layer using Mott scattering. For spontaneously magnetized samples, values of polarization at room temperature were observed in a range from 10% to 46% and the polarization direction was 〈1 1 0〉 orientation of substrate tungsten, which agreed with an easy axis of magnetization of bulky Co₂MnSi. An enhancement of polarization was observed as a consequence of applying a magnetic field of 350 G perpendicular to the emitter axis after the annealing at 800 K. This result is considered to be caused by improvement in crystallinity of the evaporated film due to annealing.     

Range expansion of the reference torque wrench calibration service to 5 kN m at NMIJ

The reference torque wrench (RTW) calibration service within the range from 5 N m to 1 kN m has been provided to industry by the National Metrology Institute of Japan (NMIJ) in the National Institute of Advanced Industrial Science and Technology (AIST). Reflecting the strong demand from Japanese industry, the calibration range was extended to 5 kN m. First, a high-precision torque transducer in the form of a torque wrench with a rated capacity of 5 kN m was developed in order to establish a calibration method for such a large RTW. Second, the calibration method was investigated using a deadweight type torque standard machine with a rated capacity of 20 kN m as a reference standard. Aimed expanded calibration range is from 200 N m to 5 kN m. As a result of calibration experiment using three transducers having different rated capacities, a relative expanded uncertainty of less than 7.0 × 10⁻⁵ could be obtained at a certain calibration point in the best case.     

Two-dimensional ordering of pentafluorobenzenethiol self-assembled monolayers on Au(1 1 1) prepared by ambient-pressure vapor deposition

Formation and surface structures of pentafluorobenzenethiol (PFBT) self-assembled monolayers (SAMs) on Au(1 1 1) prepared by ambient-vapor phase deposition were examined by means of scanning tunneling microscopy (STM) as a function of deposition temperature. PFBT SAMs formed at room temperature have disordered phases with bright aggregated domains, which are very similar to benzenethiol SAMs. As deposition temperature increases to 50 °C, partially ordered domains and large aggregated domains appeared. High-resolution STM clearly revealed that PFBT SAMs formed at 75 °C were composed of long-range, two-dimensional (2D) ordered domains, which can be described as a c(2×√3) structure. The results of this study clearly demonstrate that deposition temperature is a crucial factor for obtaining PFBT SAMs on Au(1 1 1) with a high degree of structural order.     

Uncertainty evaluation of the 1 GHz GPR antenna for the estimation of concrete asphalt thickness

The uncertainty evaluation in the measurement of pavement thickness using ground penetrating radar is depicted in this work for operating frequencies of 1 GHz. Three areas of pavement with a number of different layers and thicknesses, the influence of two different human operators and the calibration/non-calibration of the radar signal were taken into account to evaluate the uncertainty contribution.     

Pilot tone aided measurements to extend the bandwidth of radio frequency applications

A technique to extend the effective measurement bandwidth of a non-coherent vector receiver is presented. This bandwidth extension technique relies on the use of a pilot signal (known a priori), which is added on the signal of interest and is measured in a single receiver. Compared to other bandwidth extension techniques referred as stitching techniques, the proposed approach avoids error propagation in the measurement bandwidth and simultaneously enables the measurement of signals that do not contain energy in certain spectral bands.The pilot signal is created in digital stages, which tackles to large extent the requirement of the a priori knowledge of this signal. Further, the pilot signal is designed to minimize estimation errors of the proposed technique, providing enhanced performance. It is analytically shown that the error incurred by the proposed method is always lower than the error from the measurement noise.Measurement results show the method functionality with an error in the range of −50 dB of the signal measured. Finally, the usefulness of the proposed technique is illustrated by measuring the input and output of an amplifier with dynamic range in excess of 80 dB over 290 MHz using an 18 MHz bandwidth receiver. This measurement could not have been performed by existing stitching techniques.     

Method, algorithm and device for estimation of components above the harmonic frequency range up to 9 kHz

The paper presents a method of estimation of frequency groups with 200 Hz bandwidth in the frequency range from the 50th harmonic up to 9 kHz. The method consists of the application of a fast Fourier transform (FFT) for wavelet coefficients after input signal decomposition and partial synthesis for chosen frequency bands. It enables the computational complexity of the algorithm to be reduced and also attenuates influence of the fundamental component and low-frequency harmonics, as required by IEC Standard 61000-4-7. The particulars of this method are shown and analysis for a chosen wavelet family is provided. Further, the algorithm and its implementation in real device for power quality monitoring is presented. Finally, the results of measurements of two testing signals are shown. The required attenuation of fundamental component and required accuracy was obtained.