Dual-Polarized Partially Reflective Surface Antenna With MEMS-Based Beamwidth Reconfiguration

In this paper, rectification methods for micro-energy harvesting systems are proposed and estimated. We present introduce two methods. The first is a mechanical rectification. The second is semiconducting rectification which is fabricated through MEMS technology. Vibration-driven micro-energy harvesting by micro electro mechanical systems (MEMS) technology is needed because the electrical power consumption of our society is increasing. But most of the vibration-driven generators supply alternating-current and intermittent electro energy. For using, it is necessary to construct the micro energy system supplying direct current. Therefore, we present the micro energy system that is composed of vibration-driven micro-energy harvesting, rectification and energy storage. In particular, we consider the rectification in this paper. In designing, we consider that vibration-driven micro-energy harvestings are developed through MEMS technology. Compatibility between semiconductor process and MEMS process is hard to achieve in materials, temperature, contamination and so on.

The water condensation is important for wide range of industrial systems such as condensers and heat exchangers of steam power plants and refrigerators. The condensation generally has two patterns; filmwise condensation (FWC) and drop-wise condensation (DWC). DWC has one-tenth higher heat transfer coefficient than that of FWC. It has been pointed out by many investigators that DWC occurs on the hydrophobic surface and FWC occurs on hydrophilic surface. However, the durability of those hydrophobic effects was not clear enough. In order to maintain a sufficiently long DWC, it is important to understand the effect of the surface property and structure on the condensation surface in more detail. The recent advancement of MEMS (Micro Electro Mechanical System) technology enables us to change the physical nature the surface in the micro scale. It is expected that the hydrophobic surface by the MEMS technology may kept DWC for a longer time. In the present paper, we experimentally investigate the effects of thin metal film and micro structured surface on condensation pattern. Especially, our condensation experiments were performed with the micro structured surfaces by using etching and the metal thin film surfaces by sputtering for approximately 24 hours. Silicon (Si) wafer was used as a basic surface. For the metal thin films surface, we used sputtered Lead (Pb) and Titanium (Ti) on Si surface. For the micro structured surfaces, micro-structured grid was etched on Si surface with several conditions. In order to obtain the relation between the condensation pattern and surface condition, the surface conditions were measured by laser micro-scope, contact angle meter and atomic force microscope (AFM). For the metal thin films surface, condensation patterns on thin Pb film surface showed DWC. Meanwhile, condensation patterns on thin Ti surfaces showed FWC. From our results, the adsorption forces decreased with increasing contact angle on DWC for Pb. On the other hand, the adsorption forces increased with decreasing contact angle on FWC for Ti. For the micro structured surfaces, condensation pattern was FWC and contact angle decreased in our experimental results. This is because that the condensed water is accumulated in the groove on the micro structure surface.

All spacecraft rely on radiative surfaces to dissipate waste heat. These radiators have special coatings that are intended to optimize performance under the expected heat load and thermal sink environment. Typically, such radiators will have a low absorptivity and a high infrared-red emissivity. Given the dynamics of the heat loads and thermal environment it is often a challenge to properly size the radiator. In addition, for the same reasons, it is often necessary to have some means of regulating the heat rejection rate of the radiators in order to achieve proper thermal balance. The concept of using a specialized thermal control coating which can passively or actively adjust its emissivity in response to such load/environmental sink variations is a very attractive solution to these design concerns. Such a system would allow intelligent control of the rate of heat loss from a radiator. Variable emissivity coatings offer an exciting alternative that is uniquely suitable for micro and nano spacecraft applications. This permits adaptive or “smart” thermal control of spacecraft by varying effective emissivity of surfaces in response to either a passive actuator (e.g., a bi-metallic device) or through active control from a small bias voltage signal. In essence the variable emittance surface would be an “electronic louver.” It appears possible to develop such “electronic louvers” through at least three different types of technologies: Micro Electro-Mechanical Systems (MEMS) technology, Electrochromic technology and Electrophoretic technology. This paper will concentrate on the first approach using both MEMS and Micromachining technology to demonstrate variable emissivity.

Design, development, fabrication and evaluation of the dynamics of a graphene based underwater acoustic vector sensor: A simulation and experimental study

A multi-try counter-meshing gears stronglink based on micro electromechanical system (MEMS) technology is introduced, including research, design, couple and fabrication of unique signal (UQS) for some specified fields of information security. The stronglink consists of two groups of metal counter-meshing gears, two pawl/ratchet mechanisms, two driving micromotors and two resetting micromotors. The resetting micromotors make counter-meshing gears withdraw by raising pawls so that the interfered counter-meshing gears will be relieved. The energy-coupling element is a photoelectric sensor with a circular notched plate. The counter-meshing mechanism is fabricated using the ultraviolet-lithographie, galvanoformung and abformung (UV-LiGA) process and a precision mechanical technique. The stronglink can be tried several times if the correct resetting code is known.

Microelectromechanical systems (MEMS) technology has matured to the point where practical biological and chemical applications are possible. One particularly active research area is in the development of lab-on-a-chip type systems. In order to create successful lab-on-a-chip and other microfluidic systems, it is necessary to have the capability of controlling and directing fluid flow. Such functionality can be found on the front end of a microfluidic system and is known as a fluid delivery or dosing subsystem. For a MEMS micro fluid dosing system to be realized, several components are necessary. The essential components include a fluid actuator, a fluidic control device, and micro plumbing. A prototype fluid delivery system is demonstrated here using a micropump as the fluid actuator, a thermal flow sensor as the fluidic control device, and micromachined couplers as plumbing. The technology to build these components has been developed and each of these components have been fabricated and tested. A prototype constructed of discrete components has also been demonstrated. A truly integrated, channel-based fluid dosing system can be achieved through device scaling.

A double-layer 90° corrugated terahertz (THz) horn antenna based on MEMS (Micro-electromechanical System) technology is proposed. This antenna is designed at the frequency range of 400GHz–500GHz. Through adding expansion aperture and chokes to the traditional structure, good antenna performance can be obtained. From the simulated result it shows a impedance bandwidth of 400–500GHz with input return loss less than 10dB. The radiation pattern shows good symmetric beamwidth and very low cross-polarization. The peak gain varies from 13.9dBi to 16.1dBi within the frequency band 400GHz–500GHz. Dry etching MEMS technology is suitable for design of this type of antenna.

Salzberg, Arnold D MD; Bloom, Matthew B MD; Mourlas, Nicolas J PhD; Krummel, Thomas M MD Author Information

This study proposed a novel ultra-high-density (supporting up to 65,536 channels) 3D microelectrode arrays (MEAs) based on CMOS devices intended for advanced brain-computer interface (BCI) applications. The proposed MEAs structure combines the advantages of traditional models, like the Utah and Michigan type electrodes, offering the ability to precisely record and generate cortical electroencephalography (EEG) signals in 3D space. Through microelectromechanical systems (MEMS) technology, a compact and highly integrated system was fabricated, which effectively reduced losses and noise interference during signal transmission. The electrode design employed a 32 × 32 microprobe array with 64 electrodes in each microprobe shank, enabling high spatial resolution neural signal recording and stimulation. Results from electrochemical analysis suggested that the electrode had an impedance of approximately 620 kΩ at a frequency of 1 kHz and a charge injection capacity of 0.85 mC/cm², indicating its effectiveness for in vivo neurostimulation applications. This advancement in BCI technology provided significant technical support for scenarios requiring highly precise neural control, such as motor rehabilitation for paralyzed patients.

A monolithic-integrated 3-D magnetic field sensor is proposed in this paper, which is composed of four silicon magnetic sensitive transistors and a Hall magnetic field sensor. Using microelectromechanical system (MEMS) technology, the chip of the sensor was designed and fabricated on a p-type silicon wafer with a higher resistivity. At the room temperature, the magnetic sensitivities $S_{xx}$ and $S_{yy}$ on the $x$ - and $y$ -directions are 77.5 and 78.6 mV/T at power supply $V_{DD}= 5.0$ V and base injection current $I_{b}= 1.0$ mA, respectively. In addition, the magnetic sensitivity $S_{zz}$ on the $z$ -axis is 77.4 mV/T at $V_{DD}= 5.0$ V. The experimental results show that the proposed sensor has a good uniformity of magnetic sensitivity, besides achieving the measurement to 3-D magnetic fields and the cross sensitivities are less than 3% at $B\le 0.8$ T.

Small, lightweight, power-efficient and low-cost microelectromechanical system (MEMS) inertial sensors and microcontrollers available in the market today help reduce the instability of Multibeam Sonars. Current MEMS inertial measurement units (IMUs) come in many shapes, sizes, and costs - depending on the application and performance required. Although MEMS inertial sensors offer affordable and appropriately scaled units, they are not currently capable of meeting all requirements for accurate and precise attitudes, due to their inherent measurement noise. The article presents the comparison of different MEMS technologies and their parameters regarding to the main application, namely Multibeam Echo Sounders (MBES). The quality of MEMS parameters is crucial for further MBES record-processing. The article presents the results of undertaken researches in that area, and these results are relatively positive for low-cost MEMS. The paper undertakes some vital aspect of using MEMS in the attitude and heading reference system (AHRS) context. The article presents a few aspects of MEMS gyro errors and their estimation process in the context of INS processing flow, as well as points out the main difficulties behind the INS when using a few top MEMS technologies.

Precision guided munitions (PGMs) are critical to the Maneuver Battalion Commander's success on future rapidly deployed battlefields. These PGMs will provide an increase in lethality, significantly improve survivability, reduce collateral damage, minimize non-combatant casualties, and decrease the logistics burden or increase the number of kills from the standard logistics load. PGMs all require inertial measurement sensors embodied in an IMU. Until now, they have been large, expensive, and could not readily survive the high G launch environments. MEMS technology provides inherent cost savings and size reduction and is ideal for application to navigation and control systems for small missiles and munitions. Using MEMS technology, gyroscopes, accelerometers and control electronics can readily be integrated to form a tightly packaged, low-cost, extremely small, high performance IMU suitable for munition, missile, and personnel guidance as well as other applications. This paper describes the current Army development underway and its partnership with industry to achieve the necessary requirements. The program goal is to survive a 20,000 g gun launch and meet a 1/spl deg//hr, 1/2 milli-g performance capability. The MEMS IMUs will significantly reduce the cost of precision-delivered missiles and munitions, as well as expand precision delivery capability to artillery ammunitions, and thus reduce the number of required rounds by more than 30% while meeting roughly 90% of the tactical weapons fleet navigational requirements.

In this paper, numerical analysis of small-caliber projectile during external ballistic is presented. This work is aimed to find safe location to install microelectromechanical system (MEMS) inside small-caliber projectile based on history and distribution of temperature. The MEMS technology is applied to increase performance of the projectile and it must be protected from damage due to high temperature during internal and external ballistic. Heat conduction equation in cylindrical domain is used to describe transient temperature of small-caliber projectile. Finite element method with the appropriate boundary conditions is adopted to solve the heat conduction equation and to obtain temperature distribution inside projectile. Numerical results show that heat transfer behavior of the projectile at any point is greatly affected by the value of thermal conductivity of material while the external convection does not significantly effect to the heat distribution. The maximum temperatures obtained from temperature history are below threshold value of MEMS damage that is 71 oC. The MEMS technology can be installed anywhere inside the small-caliber projectile except at near top and bottom of projectile surface.

MEMS (Micro-electro mechanical system) based thermal flow sensors are getting more importance due to their ease of fabrication, small size, and high measurement resolution. In this proposed work, a Micro-Thermal flow sensor (TFS) based on MEMS technology is designed using thin film-based thermocouples. This work mainly focuses on materials selection, and identification of fabrication process followed by design, simulation and analysis of Micro-TFS. In this work, Thermopile temperature sensor is selected for Micro-TFS to overcome the drawbacks of other Temperature sensors. Aluminium and Phosphorus materials combination is selected for the Thermopile sensor, which generates a better See-beck coefficient and produces more output voltage. Fabrication process flow based on MEMS technology is identified for Micro-TFS. This proposed flow sensor is capable to measure up to 7 LPM, for a 6 mm diameter channel in Direct-flow mode and up to 110 LPM, for a 25 mm diameter channel in By-pass flow mode.

Chemical warfare agent sensor using MEMS structure and thick film fabrication method