Source Module Research Articles

A Noise Source Module for In-Situ Noise Figure Measurements From DC to 50 GHz at Cryogenic Temperatures

This letter presents the design and performance of a noise source module for in-situ noise temperature measurements at cryogenic temperatures. The noise source module operates from DC up to 50 GHz and is suitable for measurements of noise temperatures as low as a few Kelvin, achieving a measurement accuracy of about $\pm {1.2}~{\rm K}$ . The GaAs MMIC used in the module includes a well matched 50 $\Omega$ termination with better than 20 dB return loss, a heating element and an on-chip temperature sensor, hence the noise source module can directly be connected to the device under test (DUT) with no additional elements or transitions needed. The measurement can then be taken with standard noise measurement equipment. Noise temperatures as low as 13 K have been measured in Ka-band with this device. Due to the ease of use, the good matching, the extraordinary bandwidth and the less involved calibration technique, the noise source module outperforms the conventional measurement setup using a noise diode in conjunction with a cooled attenuator.

Characteristics of Heat Dissipation from a Block Heat Source Module in a Three-Dimensional Cabinet to Ambient Natural Convective Air Stream

This study combined the numerical analysis and experimental measurement to investigate the conjugate conduction and natural convection for a block heat source module in a three-dimensional cabinet filled and surrounded by air. The effects of Rayleigh number Ra, module position C1, ratio of block to air thermal conductivities Kbf, and ratio of board to air thermal conductivities Kpf are examined. Moreover, efforts are carried out to explore the influence of thermal interaction between the air streams inside and outside the cabinet.

Light-shift measurement and suppression in atomic spin gyroscope

We present a method to determine and suppress the light shift in an atomic spin gyroscope. This method doesn't require additional drive source or frequency modulation, and it is based on the dynamics of an atomic spin gyroscope to determine a clean curve as a function of the frequency of the pump beam that predicts the zero light shift. We experimentally validate the method in a Cs-(129)Xe atomic spin gyroscope and verify the results through numerical simulations. This method can also be applied to an atomic spin magnetometer based on the spin-exchange relaxation-free exchange that experiences light shift. The method is useful for atomic spin devices because it can improve long-term performance and reduce the influence of the laser.

Wireless laser spectroscopic sensor node for atmospheric CO2 monitoring—laboratory and field test

We developed a low-power, portable, wireless laser spectroscopic sensor for atmospheric CO2 monitoring. The sensor is based on tunable diode laser absorption spectroscopy with a 2-μm wavelength VCSEL as a source and wavelength modulation technique for spectroscopic signal detection. The sensor allows measurement of CO2 concentration changes with a 1σ sensitivity of 0.14 ppmv Hz−1/2. This sensor was both laboratory and field tested under varying environmental conditions. It was used to measure a soil respiration rate of topsoil in the lab and of forest floors in the field. Measurement results are compared with those of commercial non-dispersive infrared sensors and very good agreement is found.

Diversification of complex butterfly wing patterns by repeated regulatory evolution of a Wnt ligand.

Although animals display a rich variety of shapes and patterns, the genetic changes that explain how complex forms arise are still unclear. Here we take advantage of the extensive diversity of Heliconius butterflies to identify a gene that causes adaptive variation of black wing patterns within and between species. Linkage mapping in two species groups, gene-expression analysis in seven species, and pharmacological treatments all indicate that cis-regulatory evolution of the WntA ligand underpins discrete changes in color pattern features across the Heliconius genus. These results illustrate how the direct modulation of morphogen sources can generate a wide array of unique morphologies, thus providing a link between natural genetic variation, pattern formation, and adaptation.

Congruent and Incongruent Cues in Highly Familiar Audiovisual Action Sequences: An ERP Study

In a previous fMRI study we found significant differences in BOLD responses for congruent and incongruent semantic audio-visual action sequences (whole-body actions and speech actions) in bilateral pSTS, left SMA, left IFG, and IPL (Meyer, Greenlee, & Wuerger, JOCN, 2011). Here, we present results from a 128-channel ERP study that examined the time-course of these interactions using a one-back task. ERPs in response to congruent and incongruent audio-visual actions were compared to identify regions and latencies of differences. Responses to congruent and incongruent stimuli differed between 240–280 ms, 340–420 ms, and 460–660 ms after stimulus onset. A dipole analysis revealed that the difference around 250 ms can be partly explained by a modulation of sources in the vicinity of the superior temporal area, while the responses after 400 ms are consistent with sources in inferior frontal areas. Our results are in line with a model that postulates early recognition of congruent audiovisual actions in the pSTS, perhaps as a sensory memory buffer, and a later role of the IFG, perhaps in a generative capacity, in reconciling incongruent signals.

Optical Modulation of Millimeter-Wave Beams Using a Semiconductor Substrate

Modulation of millimeter and submillimeter-wave beams via an optically excited semiconductor substrate is a potentially powerful technique, but typically requires high optical illumination densities. Various methods are outlined that yield reduced illumination levels and enable optimization of the substrate. As an example device, the photo-injected Fresnel zone plate antenna (piFZPA) is presented, and we discuss the realization of this spatial modulating device at millimeter-wave frequencies. Preliminary data is presented demonstrating the realization of a 100-mm aperture F/1.2 piFZPA at 94 GHz, using a retail visible data projector as a programmable broadband light source and spatial light modulator. The demonstrated antenna can be steered precisely in two dimensions and yielded a 36-dBi directivity with excellent mainlobe symmetry, and a 12-dB peak sidelobe level.

Parameters optimization of interferometric fiber optic gyroscope for improvement of random walk coefficient degradation in space radiation environment

A random walk coefficient (RWC) prediction model of interferometric fiber optic gyroscope (IFOG) in radiation environment has been developed, combining a radiation-induced attenuation (RIA) model of fiber and a RWC expression of digital closed-loop IFOG, and verified by the radiation experiments results of two fiber coils and an experimental IFOG. Using the RWC prediction model the effects of source power, fiber length and modulation phase on the RWC of IFOG were investigated in space radiation environments. Based on the prediction model and its parameters analysis, a parameters optimization method was proposed for IFOG design to improve the RWC degradation in space radiation environments. Finally, the three parameters of the experimental IFOG were redesigned according to the optimization method.

Recording Human Electrocorticographic (ECoG) Signals for Neuroscientific Research and Real-time Functional Cortical Mapping

Recording Human Electrocorticographic (ECoG) Signals for Neuroscientific Research and Real-time Functional Cortical Mapping

Recording Human Electrocorticographic (ECoG) Signals for Neuroscientific Research and Real-time Functional Cortical Mapping

Recording Human Electrocorticographic (ECoG) Signals for Neuroscientific Research and Real-time Functional Cortical Mapping

High-radiance extreme-ultraviolet light source for actinic inspection and metrology

Actinic mask defect inspection and metrology requires high-brightness extreme-ultraviolet (EUV) sources. The self-absorption of radiation limits the in-band EUV radiance of the source plasma and makes it difficult to attain the necessary brightness and power from a conventional single unit EUV source. One possible solution is through multiplexing of multiple low etendue sources. NANO-UV is delivering a new generation of EUV light source, the CYCLOPS, in which a micro-plasma-pulsed discharge source is integrated to a photon collector based on an in situ active plasma structure. The source module is characterized by high brightness, low etendue, and high irradiance at moderate output power without the use of external physical optics. Such a source could form the basic building block of EUV source through spatial-temporal multiplexing of several units to deliver the brightness and power required for actinic mask metrology. We report on the EUV source development including the extensive numerical modeling, which provided the basic parameters required for high irradiance operating regimes. A new Sn-alloy cathode material enhances the output. Based upon the multiplexing concept, a family of specially configured multiplexed source structures, the HYDRA design, is being introduced to address the mask metrology needs.

43.3: Intensity Modulation of Light Sources for Gray Scales in Projection Displays

AbstractIntensity modulation of light source(s) is proposed to achieve a drastic (logarithmic) reduction in number of time intervals that are necessary to display grayscales in DMD and other projection displays. Methods to reduce power consumption of light sources in projection system are also proposed.

Study of Metals by Femtosecond Laser Processing for Electro-Optics Applications

Femtosecond laser (FS-laser) microstructuring of metals has become a promising tool because of its non-contact nature, which allows the micromachining and direct processing of materials with a minimized volume of heat-affected zone for electro-optics applications such as light emitting diodes (LED) and solar photovoltaic (PV) lighting. This study presents ultra-short pulse (10-15 sec) FS-laser processing. Through integrating the laser source, optical system and dynamic control modules, the materials of metals with micro-scale or nanoscale structures can be fabricated. In traditional processing such as semiconductor processing, development, exposure and etching necessitate expensive equipment and time-consuming tasks. With FS-laser processing, high-precision patterns are obtained, which will be a great benefit to keeping costs down. In this study, the wavelengths of FS-laser ablation are employed using visible and infrared light. To make a breakthrough in electro-optics processes, the CIGS thin-film of solar cells in metal process can be easily produced by the FS-laser. The ablation speed of the FS-laser for thin film layer CIGS solar cells can reach 2000 mm/s which is faster than the current Nd:YAG laser machine (~1000 mm/s). On the other hand, the minimum size of metal lines can be controlled to a value that is lower than 40 µm. Furthermore, green energy can be effectively developed for the future.

Demonstration of a home projector based on RGB semiconductor lasers

In this paper, we demonstrate a high-definition 3-liquid-crystal-on-silicon (3-LCOS) home cinema projection system based on RGB laser source modules. Both red and blue laser modules are composed of an array of laser diodes, and the green laser is based on an optically pumped semiconductor laser. The illumination engine is designed to realize high energy efficiency, uniform illumination, and suppression of speckle noise. The presented laser projection system producing 1362 lm D65 light has a volume of about 450×360×160 mm3.

One Quiz File, Several Modes of Delivery

This report offers online course designers, particularly those keen on using Moodle CMSs, a means of diversifying accessibility to their educational materials via multiple modes of delivery that do not require the creation of numerous files and formats for just one activity. The author has made contributions to the development of an open source module for Moodle known as QuizPort and has collaborated with the creator of QuizPort to explore methods for using the module such that content added to it can be more smoothly delivered via smart phone, tablet, or handheld game console. Key points to consider when designing online content for a variety of devices are addressed.

IEEE 802.15.7 visible light communication: modulation schemes and dimming support

Visible light communication refers to shortrange optical wireless communication using visible light spectrum from 380 to 780 nm. Enabled by recent advances in LED technology, IEEE 802.15.7 supports high-data-rate visible light communication up to 96 Mb/s by fast modulation of optical light sources which may be dimmed during their operation. IEEE 802.15.7 provides dimming adaptable mechanisms for flicker-free high-data-rate visible light communication.

Establishment and application of source/sink-based agricultural non-point source pollution model

Improving control standards of point(PSP) and non-point(NSP) source pollutions are recent highlights of water and environmental issues.Agricultural non-point source pollution(AGNSP) problems caused especially by heavy use of chemical fertil-izers and pesticides are prominent in this regard.Quantitative research on pollution loads is the basis of control standard,evaluation and management of AGNSP.Using AGNSP and unit-load characteristics,an AGNSP model was developed that uses source/sinks modules determine the complex migration routes of pollutants.The source module was further divided into farmland irrigation drainage and farmland contaminant concentration estimation sub-modules.The sink module was also divided into farmland drainage and pollutant migration/transformation sub-modules.By integrating the modules,a complete AGNSP load model was therefore es-tablished.The integrated AGNSP model was tested in the Qingtongxia Irrigation District(QID) in upstream reaches of the Yellow River.The 2008 crop pattern was used in the developed AGNSP model to simulate AGNSP load and output in QID.Based on the simulation results,salinity,total phosphorus,total nitrogen,nitrate nitrogen and ammonia nitrogen in QID were 470 099 t,98.17 t,3 593 t,2 122 t and 426 t,respectively.The application of the established AGNSP model indicated that the model presented prefer-able simulated results,and was practicable in the similar studies.

RELATIVISTIC MODEL ON PULSAR RADIO EMISSION AND POLARIZATION

We have developed a relativistic model for pulsar radio emission and polarization by taking into account of detailed geometry of emission region, rotation and modulation. The sparks activity on the polar cap leads to plasma columns in the emission region and modulated emission. By considering relativistic plasma bunches streaming out along the rotating dipolar field lines as source of curvature radiation, deduced the polarization state of the radiation field in terms of the Stokes parameters. We have simulated a set of typical pulse profiles, and analyzed the role of viewing geometry, rotation and modulation on the pulsar polarization profiles. Our simulations explain most of the diverse behaviors of polarization generally found in pulsar radio profiles. We show that both the `antisymmetric' and `symmetric' types of circular polarization are possible within the frame work of curvature radiation. We also show that the `kinky' nature in the polarization position angle traverses might be due to the rotation and modulation effects. The phase lag of polarization position angle inflection point relative to the phase of core peak also depends up on the rotationally induced asymmetry in the curvature of source trajectory and modulation.

Fault Detection and Classification in Plasma Etch Equipment for Semiconductor Manufacturing $e$-Diagnostics

A method of fault detection and classification (FDC) for semiconductor manufacturing equipment <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$e$</tex></formula> -diagnostics using equipment data is presented. Detecting faulty processes, identifying any anomaly at their onsets, and rapidly classifying the root cause of the fault are crucial for maximizing equipment utilization in current semiconductor manufacturing; however, tool data acquired from production equipment contains much information that is often challenging to analyze due to its sheer volume and complexity. In this paper, modular neural network (MNN) modeling is presented as a method for fault detection modeling in plasma etching. Based on the result from the MNN modeling, a tool data set is grouped according to its related subsystems, and FDC is performed using Dempster-Shafer (D-S) theory to address the uncertainty associated with fault diagnosis. Subsystem level fault detections, such as radio frequency (RF) power source module, RF power bias module, gas delivery module, and process chamber module, are presented by combining related parameters, and successful fault detection is achieved. The evidential reasoning of RF probe is also beneficial for the detection of chamber leak simulation, and the classification of fault is made by further investigating voltage signal of RF probe. Successful fault detection in subsystem level with zero missed alarms was demonstrated using D-S theory of evidential reasoning, and the classification for finding root cause of the fault is presented in the chamber leak fault simulation. We realized that successful FDC can be accomplished by combining various related information and by incorporating engineering expert knowledge.

Modeling Small Scale Solar Powered ORC Unit for Standalone Application

When the electricity from the grid is not available, the generation of electricity in remote areas is an essential challenge to satisfy important needs. In many developing countries the power generation from Diesel engines is the applied technical solution. However the cost and supply of fuel make a strong dependency of the communities on the external support. Alternatives to fuel combustion can be found in photovoltaic generators, and, with suitable conditions, small wind turbines or microhydroplants. The aim of the paper is to simulate the power generation of a generating unit using the Rankine Cycle and using refrigerant R245fa as a working fluid. The generation unit has thermal solar panels as heat source and photovoltaic modules for the needs of the auxiliary items (pumps, electronics, etc.). The paper illustrates the modeling of the system using TRNSYS platform, highlighting standard and “ad hoc” developed components as well as the global system efficiency. In the future the results of the simulation will be compared with the data collected from the 3 kW prototype under construction in the Tuscia University in Italy.