Design and Fabrication of Compact MEMS Electromagnetic Micro-Actuator with Planar Micro-Coil Based on PCB

This paper reports a compact design of electromagnetically driven MEMS micro-actuator utilizing planar electromagnetic coil on PCB (Printed Circuit Board). The micro-actuator device consists of an NdFeB permanent magnet, thin silicon membrane and planar micro-coil which fabricated using simple standard MEMS techniques with additional bonding step. Two planar coils designs including planar parallel and spiral coil structure with various coil geometry are chosen for the study. Analysis of the device involves the investigation of electromagnetic and mechanical properties using finite element analysis (FEA), the measurement of the membrane deflection and functionality test. The measurement results show that the thin silicon membrane is able to deform as much as 12.87 µm using planar spiral micro-coil. Reasonable match between simulation and measurement of about 82.5% has been revealed. The dynamic response test on actuator driven by parallel planar coil shows that silicon membrane effectively deformed in 40 s for an input electrical power of only 150 mW. It is also concluded that planar parallel coil is considered for the simple structure and easy fabrication of the actuator system. This study will provide important parameters for the development of compact and simple electromagnetic micro-actuator system for fluidic injection system in lab-on-chip

Spin-on-Glass (SOG) based insulator of stack coupled microcoils for MEMS sensors and actuators application

A comprehensive study on the SOG (Spin-on-Glass) based thin film insulating layer is presented. The SOG layer has been fabricated using simple MEMS technology which can play an important role as insulating layer of stack coupled microcoils. The fabrication process utilizes a simple, cost effective process technique as well as CMOS compatible resulting to a reproducible and good controlled process. It was observed that the spin speed and material preparation prior to the process affect to the thickness and surface quality of the layer. Through the annealing process at temperature 425oC in N2 atmospheric for 1 h, a 750 nm thin SOG layer with the surface roughness or the uniformity of about 1.5% can be achieved. Furthermore, the basic characteristics of the spiral coils, including the coupling characteristics and its parasitic capacitance were discussed in wide range of operating frequency. The results from this investigation showed a good prospect for the development of fully integrated planar magnetic field coupler and generator for sensing and actuating purposes

Interdigitated MEMS Supercapacitor for Powering Heart Pacemaker

Power MEMS can be defined as microelectromechanical systems for power generation and energy conversion. Energy harvesting has become an increasingly popular option for powering electronic devices as a long-lasting power source. Energy scavenging is defined as the process by which the energy is derived such as vibration, solar, wind, and thermal. Energy harvesting from the environment can prolong the life cycle and reduce the maintenance costs of electronic devices. Among the various sources of energy storage, Among the various of energy storage, supercapacitor has recently gained much interest in fields such as bioMEMS, biomedical implants and power electronic devices due to its advantages such as high power density, rapid charge and discharge and unlimited number of recharge cycles. In biomedical and bioMEMS systems, an energy storage device is needed to power other active biomedical devices within the system. For implantable devices such as a heart pacemaker, the power requirement is in the range of 30–100 μW. Microsupercapacitors play an important role in energy harvesting system, such as collecting energy from ambient energy sources. Human body is very resourceful in generating micropower in the form of heat dissipation, deformation of elastic tissue, and motion. Due to the advantages of MEMS energy harvesting system, the system can be use widely for biomedical implant devices, such as heart pacemakers and hearing aids, and can be used for a long time and without the need for battery replacement. In this work, planar and double-stacked interdigital electrode supercapacitor designs were modeled using Coventorware software. From simulation, it is observed that for planar structure, the specific capacitance is 0.22 mF/cm−2, and for double-stacked structure specific capacitance can be increased to 0.48 mF/cm−2. In terms of specific power, the planar structure produces 0.99 mW/cm−2, and the double-stacked structure produces 2.18 mW/cm−2. These results highlight the superiority of the double-stacked MEMS interdigital supercapacitor design compared with its planar counterpart in terms of charging capacity and electrical performance, thus making it favorable for powering heart pacemaker

Thermo-pneumatic micropump for drug delivery applications

Micropumps constitute an essential part of precise delivery and directional volume control of fluid in a microfluidic system. In biomedical applications, micropump is widely used especially in drug delivery, biological fluid transmission, organic analysis, liquid measurement, and many more. In this paper, the concept and design structure hence fabrication of the Thermopneumatic micropump prototype are explained. The experimental measurement of the micropump employing planar diffuser nozzle in transmits fluid is also presented. Thermopneumatic micropump is comprised of three different components which are the microheater on the bottom, the flexible thin membrane that acts as an actuator, and the planar diffuser nozzle on the top to channel the fluidic. These three components were fabricated separately due to the different materials and techniques used in each component. Finally, the whole micropump system was integrated using an anodic bonding technique. Bulk micromachining technique was used to fabricated the chamber and thin-film membrane, surface micromachining technique for the microheater while replica molding technique was used for the planar diffuser nozzle. The whole diameter size for the micropump was 25 x 20 x 1.6 mm respectively. The microscope image recorded video and data was used during the experimental measurement, to observed and calculate the flow rate of meniscus motion flow in the outlet tube of the micropump. At the end of the experiment, the flow rate range of the micropump measure was approximately 770pL to 12.5nL, when the output of 2-12Vdc was applied to the microheater. This flow rate range is very suitable for drug delivery applications

THE ELECTRICAL AND MECHANICAL CHARACTERIZATION OF SILICON BASED ELECTROMAGNETIC MICRO-ACTUATOR FOR FLUID INJECTION SYSTEM

Electrical and mechanical properties of Electromagnetic (EM) micro-actuator with silicon membrane has been characterized. The study is aimed to see the effect of the geometry and the structure of the actuator system on the actuating performance of the silicon-based membrane for fluid injection purposes. The actuator system consists of two main parts, namely, the electromagnetic part that generates an electromagnetic field and the magneto-mechanical part that enable the membrane deformation depending on the magnetic force on the silicon membrane. A standard MEMS process was implemented to fabricate the actuator system with an additional bonding between the actuator part and microfluidic part to complete the system for fluid injection purpose. The simulation using COMSOL Multiphysics was done to see the generation of the magnetic force and to see its effect on the membrane deformation. It was found that the height of the generated magnetic force increases significantly with the applied power. The measurement of the membrane deformation done at a 20-µm silicon membrane showed a maximum deflection of 4.6 µm. The measurement results of the electrical characteristic of the device were compared with the simulation to validate the analysis. This study is very important to get the general insight of the silicon-based actuator membrane capability for the fluidic injection system in lab-on-chip

Analisis prestasi penuai tenaga mikro frekuensi radio berkuasa rendah menggunakan antena MEMS bagi rangkaian sensor tanpa wayar

Kebelakangan ini, terdapat kecenderungan minat yang semakin meningkat dari para penyelidik menggunakan tenaga ambien bagi menghidupkan peralatan elektronik menggunakan pelbagai teknik penuaian tenaga. Penuaian tenaga mikro adalah teknik yang berpotensi untuk menukar tenaga ambien dari persekitaran kepada tenaga elektrik. Rangkaian sensor tanpa wayar memerlukan sumber tenaga elektrik yang berterusan untuk mengaktifkannya dan sumber tenaga ambien frekuensi radio (RF) yang sentiasa wujud dipersekitaran sangat sesuai digunakan. Oleh itu, penuai tenaga mikro RF yang direkacipta dan dibangunkan terdiri dari litar padanan galangan, pendarab voltan dan litar pengatur tidak memerlukan sumber tenaga luar untuk mengaktifkannya. Litar penuai tenaga mikro RF ini dibina dan disimulasi menggunakan perisian PSPICE dengan menyambungkan perintang beban 1 MΩ. Pada kuasa masukan -20 dBm atau 10 μW yang ditangkap oleh antena MEMS, nilai voltan dan arus keluaran yang dihasilkan dalam litar penuai tenaga ini masing-masing adalah 2.36 V dan 1.7 mA. Manakala, peratusan kecekapan maksimum bagi keseluruhan litar penuai tenaga mikro RF ini adalah 55.7%. Nilai kuasa keluaran yang dihasilkan iaitu 40.12 mW adalah lebih tinggi berbanding nilai kuasa masukan iaitu 10 μW. Penuai tenaga mikro RF ini mampu untuk mengaktifkan rangkaian sensor tanpa wayar dengan keperluan arus masukan minimum 1 mA. Susunatur litar bersepadu menggunakan teknologi CMOS 180 nm bagi litar pendarab telah berjaya dibangunkan dengan saiz yang sangat kecil iaitu 22.48 x 56.96 μm2 sebagai pembuktian litar boleh difabrikasi sebagai cip litar bersepadu

Atmospheric pressure chemical vapour deposition growth of graphene for the synthesis of SiO2 based graphene ball

Graphene is a prominent carbon nanomaterial with fascinating characteristics such as high conductivity and very high charge carrier mobility at low temperatures. Numerous synthesis methods for graphene have been established. Chemical vapour deposition (CVD) is among the most successful methods to fabricate high-quality graphene. However, metal-catalyzed growth is used in virtually all of the CVD techniques mentioned. To remove these metal catalysts and relocate the graphene to the necessary dielectric substrate (SiO2/Si or quartz), complex and sophisticated post-growth methods must be used, which limits the usage of graphene in practical electronic components. In the present work, we conducted a preliminary study to determine the suitable methane(CH4) flowrate, which could be used to synthesise SiO2 based graphene ball. Few-layer graphene was grown on a large area of copper(Cu) surface using 20 sccm CH4 in atmospheric pressure CVD (APCVD). The influence of CH4 flowrate on graphene growth has been investigated. Graphene was deposited on a metal catalyst substrate at optimum temperatures of 1000 °C

Mechanical impact in disk mill for producing controlled rice husk particle size by changing impactor shapes and disk rotation speeds

The purpose of this study was to evaluate regulation of mechanical impact (i.e. impactor sizes and shapes) on triangle, cylinder, and cube as well as disk rotation speed (from 600 to 1500 rpm) in disk mill for controlling size-reduction process. As a model of size-reduced material, rice husk was selected. The study was done by evaluating the final milling product size, which was completed by the measurement of energy impact during the milling process. Experimental results showed that the product size was controllable in the range of between 50 and 1000 μm. The impactor sizes and shapes influenced the contact diameter and area of impactor for making more materials being collided, whereas disk rotation speed led to giving more collision number (between rice husk and impactor) and increasing impact from the collision (due to less time contact during collision). This study provides an important information, which can be further generalized in the use of milling process as a tool for materials size-reduction and mechanochemical process

Overcoming voltage fluctuation in electric vehicles by considering Al electrolytic capacitor-based voltage stabilizer

Battery pack used in electrical vehicles (EVs) have developed fastly nowadays and are important due to its capability to stores electric charge. However, it is still found that there is an electrical voltage fluctuations due to sudden load changes or faults in the power system. To overcome this problem, the conventional strategy focuses on using voltage stabilizer with inductor-capacitor resonant circuits, leaving the problem of using capacitors at cryogenic temperatures. Herewith, we design a vehicle automatic voltage stabilizer (VAVS) operating at room temperature. The VAVS consists of nine main components, including resistors, capacitors, transistors, and diodes arranged with a specific composition to stabilize the voltage. By considering Al electrolytic capacitor, type of diode, resistor, and transistor, the VAVS device stabilizes the input voltage from 10-15V to obtain an output voltage of 12V. Then, by varying the engine rotation speed of vehicle, VAVS applied in vehicle battery supplies a constant voltage of about 12.1 V. The lowest line regulation analysis reveals a regulated voltage fluctuation of 0.17%/V. Our result shows that VAVS design works at room temperature, overcomes the voltage fluctuation and complies with the standard regulation of voltage stabilizers

Statistical optimization of zinc oxide nanorod synthesis for photocatalytic degradation of methylene blue

In this work, synthesis process parameters of Zinc Oxide nanorods (ZnO NRs) photocatalyst is optimized using Taguchi Method to obtain the highest degradation rate of Methylene Blue dye, MB. The Taguchi L27 (38) orthogonal array technique was used to determine the optimum conditions for the synthesis of the nanostructured photocatalyst. Eight important synthesis process parameters were chosen in the analysis while the effects of the parameters were studied using signal-to-noise (S/N) ratio analysis using minitab-16. The ZnO NRs photocatalyst was synthesized via solution process route based on the parameters obtained from the layout of the orthogonal arrays. The optimized synthesized nanorods was then characterized using field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), photoluminescence (PL), ultraviolet-visible near-infrared (UV-VIS-NIR), and Raman spectroscopies while the photodegradation of MB was determined by UV-VIS spectrum analysis under ultraviolet light irradiation. The results show that ZnO NRs with hexagonal wurtzite structure and bandgap energy of 3.25 eV have been obtained. The Taguchi analysis based on simulated experimental runs predicted the highest MB degradation percentage of 17.12% that can be achieved under optimum process conditions. Meanwhile, experimental photocatalytic degradation of MB using ZnO NRs synthesized under the same optimum condition achieved a degradation percentage of 17.27%, which deviates only 0.88% from the predicted value. This analysis could give an approach to optimize the synthesis process to ensure the good performance of nano-photocatalyst for the photodegradation of organic contaminations in industrial wastewater in a short time and cost-effective process