Dipole Antenna Printed on Paper Substrate for WLAN Applications

International audienceThe design of a dipole antenna printed on a paper substrate is presented in this paper. The antenna which integrates a compact balun is devoted for dual-band 2.4/5 GHz WLAN applications. The antenna is based on a double-side printed multilayer paper substrate and is fed with a coaxial cable for the testing. The simulated results of the whole structure are also presented in detail and compared with the measured performances

A novel screen-printed multi-component nanocomposite ink with a pressure sensitive electrical resistance functionality

Here, a novel functional ink is described that is composed of multiple nanoscale components and exhibits pronounced touch pressure sensitive electrical properties ideal for applications in switching, sensing and touch sensitive surfaces. The ink can be screen-printed and the as-printed ink displays a large and reproducible touch pressure sensitive electrical resistance and, in contrast to some other composite materials, the resistance changes occur down to the smallest applied pressures. Detailed scanning electron microscopy shows the complex nanoscale structure of the composite that is critical for the electrical behavior. Current-voltage measurements, under static compressive loading, show monotonic non-linear behavior at low compression and ohmic behavior at higher loadings

Analysis and study of powerefficient sar adc for active rfid sensor

This thesis introduced an energy-efficient successive-approximation-register (SAR) analog-to-digital converter (ADC) specialized to the active sensors for low-power radio frequency identification (RFID) tag system. As part of the Internet of Things (IoT) transformation, RFID is widely used. In the application where the power supply is limited, power consumption is always a notable criterion as analog circuits such as the ADC circuit, regulator circuit, rectifier circuit and radio frequency (RF) are the common power demanding parts in the system. Normally, the requirement for a longer battery performance is closely related to low-power consumption. For the application active RFID sensor in which requires low to moderate resolution and speed as well as low-power consumption, SAR is usually used as its part of the ADC circuit. Therefore, the power-efficient SAR ADC is presented in this work. The block of SAR ADCs such as the comparator block, digital-to-analog converter (DAC) block, and sampler block is designed to meet the requirement of a low-power consumption performance measurement. This thesis at first will explores the differences between multiple ADC techniques in the previous works. The proposed SAR ADC is presented to enhance the power consumption of SAR ADC in the active RFID sensor application through the implementation of a single-input comparator with the switched-capacitor DAC. In this form of architecture, there is only one input to the comparator, and only one set and a split sampling capacitor in the switched capacitor DAC to generate the required reference levels. The difference in input and output voltage of the proposed SAR ADC is the indication for the low-power design. The influence of parasitic capacitance is reduced to the extent of becoming a non-factor. The parameters of the SAR ADC are the resolution of 8-bit, the sampling frequency of 500 kHz, the supply voltage of 1 V, and the 0.18 μm complementary metal-oxide-semiconductor (CMOS) technology. The power consumption of the proposed SAR ADC is 2.3 μW which is estimated at around 25.8% improvement from the previous work. The demands for low-power consumption of RFID active sensor is well examined. The validity of the proposed design has been proven by the simulation results

An Inkjet Printed Chipless RFID Sensor for Wireless Humidity Monitoring

A novel chipless RFID humidity sensor based on a finite Artificial Impedance Surface (AIS) is presented. The unit cell of the AIS is composed of three concentric loops thus obtaining three deep and high Q nulls in the electromagnetic response of the tag. The wireless sensor is fabricated using low-cost inkjet printing technology on a thin sheet of commercial coated paper. The patterned surface is placed on a metal backed cardboard layer. The relative humidity information is encoded in the frequency shift of the resonance peaks. Varying the relative humidity level from 50% to 90%, the frequency shift has proven to be up to 270MHz. The position of the resonance peaks has been correlated to the relative humidity level of the environment on the basis of a high number of measurements performed in a climatic chamber, specifically designed for RF measurements of the sensor. A very low error probability of the proposed sensor is demonstrated when the device is used with a 10% RH humidity level discrimination

Comparative Study of Inkjet-Printed Silver Conductive Traces With Thermal and Electrical Sintering

Thermal sintering has traditionally been the most popular sintering method to enhance conductivity after the printing process in the manufacturing of printed electronics. Nevertheless, in recent years, there has been a growing interest in electrical sintering as an alternative method to overcome some of the limitations of thermal curing. This paper makes a comparative study of both sintering methods in terms of surface morphology, electrical dc conductance, and radiofrequency performance for different applied voltage waveforms. To this end, microstrip transmission lines have been inkjet-printed using nanoparticle-based silver ink on flexible polyimide substrate. The traces have been tested under different sintering conditions, achieving electrical sintering resistivity values only 2.3 times higher than that of bulk silver. This implies a 62% reduction in comparison with the best resistivity value achieved using thermal sintering in our samples. The main novelty of this contribution lies in the analysis of RF behavior as a function of electrical sintering conditions. Lower resistivities have been achieved with slower voltage ramps or allowing higher density current during sintering. It has also been proved that electrically sintered lines have similar RF performance than high-temperature thermally sintered lines in terms of insertion losses, regardless of their very different surface topology. Therefore, we can take advantage of the benefits that electrical sintering offers over thermal sintering regarding significant shorter sintering times maintaining suitable RF performance.This work was supported in part by the Spanish Ministry of Economics and Competitiveness under Grant CTQ2016-78754-C2-1-R

The internet of things in manufacturing innovation processes: development and application of a conceptual framework

Purpose: This study aims to contribute and enrich the scientific debate about the phenomenon called the Internet of Things (IoT) from a managerial perspective. Through the lenses of management and innovation literature, we investigate the main facts that characterize the IoT and developed a conceptual framework to interpret its evolution. The framework has then been applied to the case of a three-dimensional (3D) printing technology used for additive manufacturing. Design/methodology/approach: A theoretical analysis of the phenomenon of the IoT and its main elements has been performed to construct a conceptual framework in a managerial fashion able to describe the evolutionary impacts of the phenomenon on the manufacturing industry. Findings: Through consequential steps, namely radical, modular, architectural and incremental innovation, and by adopting and integrating the Henderson and Clark model, we explain the cornerstones of the evolutionary impact of the IoT on the manufacturing industry. Finally, we apply our framework to the case of additive manufacturing and 3D printing. Practical implications: Our framework’s practical value is related to its employability in interpreting and possibly forecasting the evolution of manufacturing industries thanks to the advent of the IoT, allowing managers to capture value arising from technological changes. Originality/value: This study offers a clear and simple model to interpret the impacts of the IoT. Such a goal has been obtained by systematizing the disconnected research on the topic and arranging such contributions into solid paradigms of the managerial literature

Progress and prospects in flexible tactile sensors

Flexible tactile sensors have the advantages of large deformation detection, high fault tolerance, and excellent conformability, which enable conformal integration onto the complex surface of human skin for long-term bio-signal monitoring. The breakthrough of flexible tactile sensors rather than conventional tactile sensors greatly expanded application scenarios. Flexible tactile sensors are applied in fields including not only intelligent wearable devices for gaming but also electronic skins, disease diagnosis devices, health monitoring devices, intelligent neck pillows, and intelligent massage devices in the medical field; intelligent bracelets and metaverse gloves in the consumer field; as well as even brain–computer interfaces. Therefore, it is necessary to provide an overview of the current technological level and future development of flexible tactile sensors to ease and expedite their deployment and to make the critical transition from the laboratory to the market. This paper discusses the materials and preparation technologies of flexible tactile sensors, summarizing various applications in human signal monitoring, robotic tactile sensing, and human–machine interaction. Finally, the current challenges on flexible tactile sensors are also briefly discussed, providing some prospects for future directions

In-Situ Measurements in Microscale Gas Flows—Conventional Sensors or Something Else?

Within the last few decades miniaturization has a driving force in almost all areas of technology, leading to a tremendous intensification of systems and processes. Information technology provides now data density several orders of magnitude higher than a few years ago, and the smartphone technology includes, as well the simple ability to communicate with others, features like internet, video and music streaming, but also implementation of the global positioning system, environment sensors or measurement systems for individual health. So-called wearables are everywhere, from the physio-parameter sensing wrist smart watch up to the measurement of heart rates by underwear. This trend holds also for gas flow applications, where complex flow arrangements and measurement systems formerly designed for a macro scale have been transferred into miniaturized versions. Thus, those systems took advantage of the increased surface to volume ratio as well as of the improved heat and mass transfer behavior of miniaturized equipment. In accordance, disadvantages like gas flow mal-distribution on parallelized mini- or micro tubes or channels as well as increased pressure losses due to the minimized hydraulic diameters and an increased roughness-to-dimension ratio have to be taken into account. Furthermore, major problems are arising for measurement and control to be implemented for in-situ and/or in-operando measurements. Currently, correlated measurements are widely discussed to obtain a more comprehensive view to a process by using a broad variety of measurement techniques complementing each other. Techniques for correlated measurements may include commonly used techniques like thermocouples or pressure sensors as well as more complex systems like gas chromatography, mass spectrometry, infrared or ultraviolet spectroscopy and many others. Some of these techniques can be miniaturized, some of them cannot yet. Those should, nevertheless, be able to conduct measurements at the same location and the same time, preferably in-situ and in-operando. Therefore, combinations of measurement instruments might be necessary, which will provide complementary techniques for accessing local process information. A recently more intensively discussed additional possibility is the application of nuclear magnetic resonance (NMR) systems, which might be useful in combination with other, more conventional measurement techniques. NMR is currently undergoing a tremendous change from large-scale to benchtop measurement systems, and it will most likely be further miniaturized. NMR allows a multitude of different measurements, which are normally covered by several instruments. Additionally, NMR can be combined very well with other measurement equipment to perform correlative in-situ and in-operando measurements. Such combinations of several instruments would allow us to retrieve an “information cloud” of a process. This paper will present a view of some common measurement techniques and the difficulties of applying them on one hand in a miniaturized scale, and on the other hand in a correlative mode. Basic suggestions to achieve the above-mentioned objective by a combination of different methods including NMR will be given