An X band RF MEMS switch based on silicon-on-glass architecture

Communication systems such as those used on satellite platforms demand high performance from individual components that make up the various systems and sub-systems. Switching and routing of RF signals between various modules is a routine and critical operation that determines the overall efficiency of the entire system. In this paper, we present the design and fabrication aspects of a direct contact RF MEMS switch designed to operate in the X band (8–12 GHz) with a target insertion of about 0·5 dB and isolation better than 30 dB. The actuation voltage is expected to be around 50 V. The die size is designed to be 3 mm (H) × 3 mm(W) × 2 mm(H). The switch is built from a low residual stress device layer of a highly conducting (0·005 Ohms-cm) silicon on insulator (SOI) wafer. After subsequent lithographic steps, the wafer is bonded to a Pyrex glass wafer which has been previously patterned with gold transmission lines and pull in electrodes. Being built from a single crystal silicon structure, the mechanical robustness of the actuator is much greater than the those in similar membrane-based devices. A 6 mask fabrication process utilizing Deep Reactive Ion Etching to achieve high aspect ratio stiction free structures was developed and implemented. Devices from the first fabrication run are being analysed in our laboratory.     

Epoxy oleic acid inQuamoclit seed oils

Quamoclit phoenicea Choisy andQuamoclit coccinea Moench. (Syn.Ipomoea coccinea Linn), belonging to the Convolvulaceae plant family, was found to contain palmitic (22.2%, 33.3%), stearic (11.3%, 1.7%) oleic (13.5%, 14.6%), linoleic (40.1%, 30.8%), vernolic (6.4%, 10.2%), arachidic (3.5%, 6.8%) and behenic (3.8%, 2.6%) acids, respectively.     

Structural and Dielectric Properties of Lead-Free Zr-Doped Barium Titanates

Lead-free BaZr _x Ti_1–xO₃ ferroelectrics (x = 0.2, 0.4, 0.6, 0.8) were synthesized by conventional double-sintering technique. The structural, morphological, and dielectric properties of BaZr _x Ti_1–xO₃ were investigated as a function of zirconium content x. A single-phase perovskite structure of tetragonal ceramics was identified by XRD. The SEM images of the ferroelectrics exhibit fine grains of varied porosity. All synthesized samples exhibited dielectric dispersion at low frequencies.     

Model Prediction and Experimental Study of Material Removal Rate in Micro ECDM Process on Borosilicate Glass

Silicon - Miniaturization of products has become a major technological challenge in production industries. Material removal in microscopic and sub-microscopic level has become a demand for...     

Analysis of couple stress nanofluid flow under convective condition in the temperature-dependent fluid properties and Lorentz forces

In recent years, a great deal of interest has been generated in modern micro- and nanotechnologies for micro/nano-electronic devices. These technologies are increasingly utilizing sophisticated fluid media to enhance performance. Among the new trends is the simultaneous adoption of nanofluids and biological micro-organisms. Motivated by bio-nanofluid vertical channel oxygenators in medical engineering, in the current work, a mathematical model is developed to examine the flow of mixed convective couple-stress nanofluids in a vertical channel with a transverse magnetic field, fluid viscosity that changes with temperature, and thermal conductivity. The non-Newtonian model follows Brownian motion and heat spread by nanoparticles in a fluid under coupled stress. Highly linked, nonlinear regulating equations are translated into nondimensional equations using relevant variables. The governing equations are then turned into a form with no dimensions. The Keller-box technique, a second-order finite difference method for solving second-order equations, is used to solve them numerically. On the other hand, the effects of different non-Newtonian flow parameters, such as the couple stress fluid parameter, the magnetic parameter, the variable fluid viscosity, the variable thermal conductivity parameters, the Brinkman number, the nanofluid and buoyancy parameters, and the rate of chemical reaction parameter, are carefully studied. The velocity, temperature, and concentration fields are calculated over a wide range of possible values for the relevant parameters.     

Generation and Characterization of Borosilicate Glass Nanoparticles using in-House Developed μ-ECDM Setup

Silicon - Micro-Electro Chemical Discharge Machining (μ-ECDM) has proved its potential to generate features, structures, and textures on various engineering materials, particularly glass....     

Optimization of the Parameters Influencing the Control of Dual-Phase AISI1040 Steel Corrosion in Sulphuric Acid Solution with Pectin as Inhibitor Using Response Surface Methodology

Protection of Metals and Physical Chemistry of Surfaces - In this work, AISI1040 steel specimens have undergone appropriate heat treatment schedules for the development of ferrite-martensite and...     

Machining,Characterization and Optimization: A Novel Approach for Machining Channels on Silicon Wafer Using Tailor-Made Micro Abrasive Jet Machining

Silicon - Literature reveals that machining a silicon wafer is very arduous due to its high brittle nature and low fracture toughness. Researchers have attempted to machine features on a silicon...     

An experimental investigation on the adhesive,shear strength,and failure modes of glass fibre reinforced polymer flat-joggle-flat composite joints over different bonding techniques

The utilisation of composite materials, especially glass fibre-reinforced polymer has significantly developed as a result of design innovations in aircraft applications. Joints are a major issue as they are the weak point of composite construction. In this study, considering a flat-joggle-flat joint over the single-lap-joint, the effect of different manufacturing techniques on co-bonding, secondary-bonding, and co-curing for flat-joggle-flat joints on the shear behaviour and dynamic characteristics were investigated. The results affirmed that flat-joggle-flat joints increased the load-carrying capacity by 110 % compared to single-lap joint. In continuance, results revealed that co-cure flat-joggle-flat joints enhanced the load by 86.43 % and 20.00 %, along with increased shear strength of 8.9 MPa over co-bonding and secondary-bonding. Field emission scanning electron microscopy reveals that destructive failure occurs at joints in co-bonding and secondary-bonding due to an increase in stress between the adhesive and the adherend, which can lead to fibre failure and matrix damage. The dynamic characteristics, like fundamental natural frequency, are increased in co-cure flat-joggle-flat joint compared to co-bonding and secondary-bonding joints. The investigation reveals that innovative flat-joggle-flat joints and suitable manufacturing processes improve the shear strength, and dynamic properties of composite joints.