Layer Technology Research Articles

Multifunctional Platform with CMOS-Compatible Tungsten Microhotplate for Pirani, Temperature, and Gas Sensor

A multifunctional platform based on the microhotplate was developed for applications including a Pirani vacuum gauge, temperature, and gas sensor. It consisted of a tungsten microhotplate and an on-chip operational amplifier. The platform was fabricated in a standard complementary metal oxide semiconductor (CMOS) process. A tungsten plug in standard CMOS process was specially designed as the serpentine resistor for the microhotplate, acting as both heater and thermister. With the sacrificial layer technology, the microhotplate was suspended over the silicon substrate with a 340 nm gap. The on-chip operational amplifier provided a bias current for the microhotplate. This platform has been used to develop different kinds of sensors. The first one was a Pirani vacuum gauge ranging from 1-1 to 105 Pa. The second one was a temperature sensor ranging from -20 to 70 °C. The third one was a thermal-conductivity gas sensor, which could distinguish gases with different thermal conductivities in constant gas pressure and environment temperature. In the fourth application, with extra fabrication processes including the deposition of gas-sensitive film, the platform was used as a metal-oxide gas sensor for the detection of gas concentration.

Platforms and Protocols for the Internet of Things

Building a general architecture for the Internet of Things (IoT) is a very complex task, exacerbated by the extremely large variety of devices, link layer technologies, and services that may be involved in such a system. In this paper, we identify the main blocks of a generic IoT architecture, describing their features and requirements, and analyze the most common approaches proposed in the literature for each block. In particular, we compare three of the most important communication technologies for IoT purposes, i.e., REST, MQTT, and AMQP, and we also analyze three IoT platforms: openHAB, Sentilo, and Parse. The analysis will prove the importance of adopting an integrated approach that jointly addresses several issues and is able to flexibly accommodate the requirements of the various elements of the system. We also discuss a use case which illustrates the design challenges and the choices to make when selecting which protocols and technologies to use.

Wafer Level 3D System Integration using a Novel 3D-RDL Technology

A new wafer-level 3D system integration process that relies on a novel multi-level 3D redistribution layer technology (3D-RDL) to interconnect chips together as well as to the substrate was developed. The 3D-RDL technology is based on a single electroplating step that allows routing high density, auto-adaptive vertical copper interconnects (20 μm Line/Space “L/S”) at the edge of known-good dies as well as redistribution layer on top of the die and the substrate. Furthermore, this technology enables 3D interconnection of stacked dies using a single 3D-RDL layer. Additionally, high performance 3D inductive devices with small form factor can be integrated above-IC or above-substrate using the same 3D-RDL processing steps. These capabilities allow miniaturization and performance enhancement and make the technology ideal for various applications requiring functional heterogeneous system integration on a small footprint, such as systems for mobile and Internet-of-Things (IoT) applications, MEMS and Sensors.

New DVB‐S2X constellations for improved performance on the satellite channel

SummaryDigital Video Broadcasting via satellite second generation has experienced worldwide adoption because of its revolutionary and yet practical physical layer technology and its flexibility. Recently, the standard has been updated with several new features without changing its fundamental structure. This paper provides a high‐level discussion on several of the most important additions to the new standard with particular emphasis on some of the new signal constellations. Copyright © 2015 John Wiley & Sons, Ltd.

Shape memory fiber supercapacitors

Smart energy storage materials, which not only store electrochemical energy but also exhibit sensitivity to environmental stimuli, can provide novel multi-functionalities. Here, we report a smart shape memory fiber supercapacitor constituted with a highly stretchable shape memory polymer nanocomposite fiber substrate, multi-walled carbon nanotubes (MWCNT) conductive layer and pesudocapacitive polyaniline layer. Using layer by layer (LBL) technology, we first produce a densely packed MWCNT layer that serves as a well-developed conductive current collector network. Then polyaniline, as an active material, was deposited on the surface of the MWCNT layer to further promote the energy storage capability of the fibers. After the infiltration of a polyvinyl alchohol (PVA) based polymer electrolyte into the porous MWCNT and PANI layer, conductivity of ∼50S/cm and stretchability of more than 400% are obtained. The resultant shape memory polymer supercapacitors (SMPFSCs) not only possess shape memory properties, but also exhibit outstanding energy storage performance, with the best pseudo-capacitance exceeding ∼427F/cm3. Such design strategies can also be extended to other polymer substrates, and could open the door to smart (multi-functional) supercapacitor technologies.

Baseband unit cloud interconnection enabled by flexible grid optical networks with software defined elasticity

The evolution toward 5G mobile networks is characterized by supporting higher data rate, excellent end-to-end performance and ubiquitous user-coverage with lower latency, power consumption, and cost. To support this, the RANs are evolving in two important aspects. One aspect is “cloudification,” which is to pool baseband units to be centralized for statistical multiplexing gain. The other aspect is to use advanced optical technologies for digital and analog signal transmission in a cloud-based RAN. In this article, we focus on BBU cloud interconnection with optical layer technologies. Flexible grid optical networks with the enabling technologies are introduced to provide elastic, transparent, and virtualized optical paths between the BBU pools. To improve the elasticity and intelligence of C-RAN, we propose a software defined centralized control plane to coordinate heterogeneous resources from three domains: the BBU domain, radio domain, and optical domain. We report an experimental demonstration of elastic lightpath provision for cloud radio-over-flexible grid optical networks in a software-defined-networking-based testbed.

A 0.1 G-to-20 G integrated MEMS inertial sensor

This paper presents a novel integrated MEMS inertial sensor with a wide range of acceleration from 0.1 G to 20 G (G = 9.8 m/s2) and with a design suitable for CMOS integration. Owing to the high-density of post-processed gold and the multi-metal layer technology, we have implemented different types of single-axis MEMS capacitive inertial sensors on a single chip of 4 × 4 mm2 in area to obtain a wide sensing range. The estimated Brownian noise was between 82.4 nG/Hz1/2 and 1.11 µG/Hz1/2. The experimental results show that the MEMS sensor has higher sensing resolution than those of conventional MEMS accelerometers.

Layered Composite Material Formation Technology for the Titanium–Foam Aluminum System

Technology is proposed for liquid-phase formation of composite materials of the titanium-foam aluminum system. Mechanical properties are compared for foam aluminum and titanium–foam aluminum composite material.

System for investigation of friction properties of the road surface

Friction properties of the road surface have a great influence on the safety of automobile motion. These properties are characterized by the tyre-to-road adhesion coefficient, which is measured during the routine and acceptance investigations of roads. In the paper, the method of measurement of this coefficient is presented. For investigation of the tyre-to-road adhesion coefficient the special measurement system was developed. The main part of the system is dynamometer trailer, which makes it possible to measure the friction force between tyre and road surface. The adhesion coefficient as a quotient of the friction force and vertical load is a result of measurements. Additionally the system enables to determine the graph of the adhesion coefficient as a function of wheel slip ratio. In the paper a description of the measurement system and a principle of its operation are presented. Exemplary results of tyre-to-road adhesion coefficients measured on different roads are also presented. The results show many differences between these coefficients in dependence of road upper layer technology, degree of its wear, weather conditions, sliding velocity and others. The system originally designed for investigation of friction parameters of road surfaces can have much wider applications, for example in tyre investigations, for automotive experts, in the work of judgment witnesses and others.

Identification of technology development trends based on subject–action–object analysis: The case of dye-sensitized solar cells

Identification of technology development trends is essential for supporting decision makers in forecasting and identifying related innovation activities and industrial growth. Different from the traditional technology development trends based on keyword-based quantitative methods, which usually predict trends by finding key technologies without showing how to develop them, our method allows the identification of future direction and industry goal for the technology domain and shows detailed paths for achieving them. Thus, our method has constructed technology roadmapping (TRM) with seven layers (material, technology, influencing factor, component, product, goal, and future direction) on the basis of subject–action–object analysis. The detailed paths for developing this as a trend can be shown by the interaction among these TRM elements. In addition, the method also sets three indicators as a discriminating standard to find key players that can support the trend by engaging technological innovation scenarios. The case of a dye-sensitized solar cell (DSSC) is exemplified to illustrate the detailed procedure of our method. The results reveal the development trends in the field of DSSCs, the detailed paths to achieve them, and key countries that support them.

On the Achievable Performance-Complexity Tradeoffs of Relay-Aided Space Shift Keying

Future cellular networks require transmission technologies and protocols that are energy-efficient, and that can meet the growing demands of mobile data traffic with the best performance versus complexity tradeoff. The recently proposed single-RF space shift keying (SSK-) multiple-input-multiple-output (MIMO) transmission scheme is one of such physical layer technology that satisfies these criteria. In general, SSK requires a large number of antenna elements (with only one of them active) at the transmitter for high data rate transmission. This makes SSK particularly useful for the downlink of cellular systems. In this paper, we exploit the virtual MIMO concept to design SSK transmission schemes for the uplink of cellular networks. The idea is to take advantage of nearby nodes to the mobile terminal as a “virtual spatial-constellation diagram,” where the information can be encoded and transmitted to the final destination. By taking into account the virtual nature of the spatial-constellation diagram, we develop advanced demodulation techniques, perform a comprehensive mathematical analysis, as well as analyze the system complexity and energy consumption. It is also shown that the proposed scheme is capable of outperforming certain state-of-the-art protocols.

Fabrication of rectangle diagnostic hole in Au hohlraum using EDM-milling

The rectangle diagnostic hole on the side of Au hohlraum was machined using electrical discharge machining milling (EDM-milling) by layer technology. The zone of the EDM was controled under the electrode and the side of the electrode was not machined. The size of diagnostic hole was characterized by OLYMPUS STM6 measuring microscope. The results indicate that the dimension precision of diagnostic hole is less than 5 m.

A survey of millimeter wave communications (mmWave) for 5G: opportunities and challenges

With the explosive growth of mobile data demand, the fifth generation (5G) mobile network would exploit the enormous amount of spectrum in the millimeter wave (mmWave) bands to greatly increase communication capacity. There are fundamental differences between mmWave communications and existing other communication systems, in terms of high propagation loss, directivity, and sensitivity to blockage. These characteristics of mmWave communications pose several challenges to fully exploit the potential of mmWave communications, including integrated circuits and system design, interference management, spatial reuse, anti-blockage, and dynamics control. To address these challenges, we carry out a survey of existing solutions and standards, and propose design guidelines in architectures and protocols for mmWave communications. We also discuss the potential applications of mmWave communications in the 5G network, including the small cell access, the cellular access, and the wireless backhaul. Finally, we discuss relevant open research issues including the new physical layer technology, software-defined network architecture, measurements of network state information, efficient control mechanisms, and heterogeneous networking, which should be further investigated to facilitate the deployment of mmWave communication systems in the future 5G networks.

Improvement of surface leakage current of 2.6 µm InGaAs photodetectors by using inductive coupled plasma chemical vapor deposition technology

Low surface leakage current is one of the prerequistites to reach the low leakage and high efficiencies of mesa type photodiodes. In this paper, we have studied the surface leakage of 2.6 µm mesa InGaAs p–i–n photodetectors by using two different passivation technologies: inductive coupled plasma chemical vapor deposition (ICPCVD) and plasma enhanced chemical vapor deposition (PECVD). It is found that the total leakage current of the detector with ICPCVD technology is significantly reduced compared to that with PECVD technology due to the decrease of the device’s surface leakage current. A TCAD-based dark current model further reveals that the reduction of the surface leakage current at the low reverse voltage is about two orders of magnitude. As a result, ICPCVD is the promising deposition technology for SiNx passivation layer on mesa InGaAs photodetectors.

The Technology Limits for Stratified Injection of Polymer Flooding

At present the development of Daqing Oilfield has entered the water pick-up period, and the polymer separate injection technology for the injection well is urgent needed. However, the difficulty of selecting well and lever for the separate injection of the injection well is relatively large due to the complexity of the Class II reservoir of geological conditions. So for The limits of technology of the geological features, the limits of technology injection of stratified polymer injection for the Class II reservoir provides a scientific basis for the development of oil fields.In this paper, taking Daqing Oilfield Sabei Development Zone as example, establish the mathematical model of polymer flooding. Determine the well and layer selection principles of layered polymer injection wells in the ClassIIreservoir timing. According to the current development situation, give the decrease in water content and the improvement value in recovery under a given measure.Through this paper, we have got production effect of layered polymer injection in the Class II reservoir of Sabei area and given quantified layered polymer injection technology limits.

Sediment resuspension under action of wind in Taihu Lake, China

A field study was undertaken to investigate the changes of the current speed, wave parameters and sediment resuspension under different wind speeds in the Taihu Lake. The Acoustic Doppler Current Profiler (ADCP) and MIDAS DWR Wave Recorder were used to collect the data of currents and waves, respectively. The characteristics of sediment resuspension were investigated by a layered sampling technology. The measurement results showed that the current speed increased in direct proportion with the wind speed. Vertical distributions of the current speed represented significant inflection points at 0.4 of the relative water depth. Both the upper and lower layers followed logarithmic distributions. The mean wind speed and wave parameters (wave height and wave energy density) showed exponential distributions, meanwhile similar distribution was found between the mean wind speed and current speed. With rising surface wind, a corresponding increase in the concentration and particle size of the Suspended Particulate Matter (SPM) was observed in the water column. Different kinds of particles could influence the SPM concentration in the water column. The critical wind speed of sediment resuspension and the corresponding sediment incipient shear stress was found to be 3.7 – 4.0 m s−1 and 0.011 N m−2, respectively. The results of this study can be used to help understand and predict the changes of flow structure and water quality induced by different wind disturbances in shallow lakes.

Selective area growth of Ge film on Si

According to low temperature Ge buffer layer and selective area epitaxy technology, we selectively grow Ge film on patterned Si/SiO2 substrate using ultra-high vacuum chemical vapor deposition. By using X-ray diffraction (XRD), scanning electron microscope, atomic force microscopy and Raman scattering spectrum, we obtain its crystal quality and the laws of stress and other parameters varying with shape size. The results show that threading dislocation density decreases with shape size decreasing. Moreover, the tensile strain of Ge layer first increases and then turns stable with the increase of shape size, which can be attributed to the formation of (113) facet during Ge selective area growth. The formation of (113) facet reduces the strain energy of epitaxial material system, and the reduction of strain energy per unit volume decreases with increasing the shape size. The root-mean-square surface roughness of the Ge epilayer with a thickness of 380 nm is about 0.2 nm, the full-width-at-half maximum of the Ge peak of the XRD profile is about 678". It is indicated that the selective area epitaxial Ge layer is of good quality and will be a promising material for Si-based optoelectronic integration.

The Study of Humidity Conditions of the Outer Walls of a “Passive House” for the Climatic Conditions of Serbia, City Nis

Existing European energy efficiency standards impose high requirements on yearly consumption of heat energy in buildings and on heat-protective qualities of cladding. One of the options of energy efficient buildings is the “passive house” with low energy consumption. As shown in this article, designs of “passive houses” have not always considered the requirements for preventing condensation in the cladding. Humidity conditions of the cladding of the “passive house” in the city Niš have been analyzed. It was found that for designing a heating system in the outer wall, with a specified outdoor air temperature, formation of condensation exists. To eliminate condensation we conceived vapor barrier layer technology from the inner surface of outer wall. Humidity conditions in the assembly of the vapor barrier layer have been calculated

Channel Models and Beamforming at Millimeter-Wave Frequency Bands

SUMMARY Millimeter-wave (mm-wave) radio is attracting attention as one of the key enabling physical layer technologies for the fifthgeneration (5G) mobile access and backhaul. This paper aims at clarifying possible roles of mm-wave radio in the 5G development and performing a comprehensive literature survey on mm-wave radio channel modeling essential for the feasibility study. Emphasis in the literature survey is laid on grasping the typical behavior of mm-wave channels, identifying missing features in the presently available channel models for the design and evaluation of the mm-wave radio links within the 5G context, and exemplifying different channel modeling activities through analyses performed in the authors’ group. As a key technological element of the mm-wave radios, reduced complexity beamforming is also addressed. Design criteria of the beamforming are developed based on the spatial multipath characteristics of measured indoor mm-wave channels.

Discussion on the Technology Application of OFDM in the Ad-Hoc Network of Unmanned Aerial Vehicle (UAV)

The coordination model of UAV network is attracting widespread attention. Considering from the flight characteristics of UAV, the Ad Hoc network should be adopted. This paper analyzes the characteristics of Ad Hoc network, and focuses on the further discussion on the physical layer technology OFDM to conclude that the application of OFDM technology in the UAV network communication can improve the data transmission capability.