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The optimization of the performance of optical modulators requires reasonably accurate predictive models for key figures of merit. The interleaved PN junction topology offers the maximum mode/junction overlap and enables the most efficient modulators for depletion-mode operation. Due to the structure of such devices, accurate modeling must be fully three dimensional (3D), representing a nontrivial computational problem. A rigorous 3D model for the modulation efficiency of a silicon-on-insulator interleaved-junction optical phase modulator with submicron dimensions is presented herein. The drift–diffusion and Poisson’s equations are solved on a 3D finite-element mesh, while Maxwell’s equations are solved using the finite-difference time-domain method on 3D Yee cells. The entire modeling process is presented in detail, and all the coefficients required by the model are presented. The model validation suggests

The fabrication process of a microparabolic reflector using isotropic xenon difluoride Xe F 2 etching technique is presented and analysed through this work for developing infrared antenna-coupled detectors. Although many parametric studies described the behaviour of this process in the literature, the non-linearity of the process and its dramatic dependency on the pattern definition result in great difficulties when adopting the process for developing a particular structure. The main focus of this work is, therefore, to present a detailed etching analysis as dictated in the proposed design providing the proper etching recipe according to the proposed structure design and its associated masking pattern. Deep insights into the process have been highlighted suggesting the necessity of the process assessment in terms of evaluating the three-dimensional etched volume rather than the etched depth. This will potentially solve the non-linearity behaviour and the pattern dependency problem. The optimum etching recipe yields approximately a total volume of 0.354 mm3 through the proper patterning mask. The resultant parabolic cavities have 75 and 13 μ m in their diameter and depth, respectively, as required for the proposed structure. The integration of a microparabolic reflector with such detectors will potentially enhance the specific detectivity of these detectors.

In this study, MWCNTs were used as a filler for epoxy thin film composites, where the thin film was fabricated using the spin coating method. We investigated the dielectric properties of the MWCNT-filled epoxy composite, with filler loading in the range from 0 to 1.5 vol%. Additionally, the effect of various type of MWCNT filler treatments using polyoxyethylene octyl phenyl ether (Triton X-100), sodium dodecyl sulfate (SDS) and 3-aminopropyltriethoxy silane (AMPTES) on the dielectric properties of epoxy thin film composites were investigated. The results showed that the increment of MWCNT loading increased the dielectric properties of the composite system. Meanwhile, chemically treated MWCNTs, especially MWCNT treated with SDS, showed good dielectric properties. Furthermore, morphological study showed an improvement in the dispersion of filler throughout the epoxy matrix in the treated composite system compared to the untreated system. TEM images also showed that treated MWCNT filler increased wall thickness of nanotube.

Since the 1940s, infrared (IR) detection and imaging at wavelengths in the two atmospheric windows of 3 to 5 and 8 to 14 μm has been extensively researched. Through several generations, these detectors have undergone considerable developments and have found use in various applications in different fields including military, space science, medicine and engineering. For the most recently proposed generation, these detectors are required to achieve high-speed detection with spectral and polarization selectivity while operating at room temperature. Antenna coupled IR detectors appear to be the most promising candidate to achieve these requirements and has received substantial attention from research in recent years. This paper sets out to present a review of the antenna coupled IR detector family, to explore the main concepts behind the detectors as well as outline their critical and challenging design considerations. In this context, the design of both elements, the antenna and the sensor, will be presented individually followed by the challenging techniques in the impedance matching between both elements. Some hands-on fabrication techniques will then be explored. Finally, a discussion on the coupled IR detector is presented with the aim of providing some useful insights into promising future work.

If we understand Moore's law and Amdahl's law then we can conclude that increasing number of CPU cores in a computing system is of no use just to attain high computation rate.We have designed a new arbitration technique which can use the CPU cores in a most optimised manner and can achieve high degree of task parallelism.The designed arbitration technique is superior to other existing arbitration technique in terms of CPU usage, bandwidth optimization and latency.The designed arbitration technique has been tested using high performance benchmark program to analyse its efficiency. Parallelization of task is considered to be a huge challenge for future extreme-scale computing system. Sophisticated parallel computing system necessitates solving the bus contention in a most efficient manner with high computation rate. The major challenge to deal with is the achievement of high CPU core usage through increased task parallelism by keeping moderate bus bandwidth allocation. In order to tackle the aforesaid problems, a novel arbitration technique, known as Parallel Adaptive Arbitration (PAA) has been proposed for the masters designed according to the traffic behaviour of the data flow. These masters are implemented using a synthetic benchmark program that measures sustainable memory bandwidth and the corresponding computational rate. The proposed arbitration technique is a strong case in favour of fair bandwidth optimization and high CPU utilization, as it consumes the processor cores up to 77% through high degree of task parallelization and also reduces bandwidth fluctuation. Some of the works published so far in this area are reviewed, classified according to their objectives and presented in an organised manner with a conclusion. Display Omitted

The ambient vibration-based micro electromechanical systems (MEMS) piezoelectric harvester has become an important subject in most research publications. Providing a green and virtually infinite alternative power source to traditional energy sources, this harvester will significantly expand the applications of wireless sensor networks and other technologies. Using piezoelectric materials to harvest the ambient vibrations that surround a system is one method that has seen a dramatic rise in the power-harvesting applications. The simplicity associated with piezoelectric micro-generators makes them very attractive for MEMS applications in which ambient vibrations are harvested and converted into electric energy. These micro generators can become an alternative to the battery-based solutions in the future, especially for remote systems. In this paper, we proposed a model and presented the simulation of a MEMS-based arrayed energy harvester under ambient vibration excitation using the Coventorware approach. This arrayed cantilever-based MEMS energy harvester that operates under ambient excitation of frequency band of 67 to 70 Hz, within a base acceleration of 0.2 to 1.3 g produces an output power of 6.8 μw and 0.4 volts at 20.1 k-ohms load.

This paper emphasis on state-of-the-art of the earlier until the current trend and demand, principles, design considerations, key performance and fabrication technology of RF MEMS switch devices developed over the past few years. RF MEMS switch performance and features such as actuation voltage, insertion loss, isolation and ease with cost of fabrication and applications are compared and discussed.

Kalman filtering is a well-established methodology used in various multi-sensor data fusion applications. In our experiment, we first obtain measurements from the accelerometer and gyroscope and fuse them using Kalman filter in an inertial measurement unit (IMU). We estimate Kalman filter output and estimation error. The affect of process noise and measurement noise on estimation error is tested. It is explored that the measurement noise has significant role to increase estimation error in the data fusion process.

The world is facing the challenge of global warming and climate change issues. The objective of the study is to examine the meteorological data that constitute the environment and their balance has prevailing effect on the global warming. The meteorological data in our study refers to temperature, humidity, carbon dioxide and oxygen. We deploy our own customized hardware setup to obtain the data. Provided with this basic data, many significant parameters such enthalpy, dew point, humidity ratio, actual vapor pressure, saturated vapor pressure, partial vapor pressure and specific volume could be derived. We have presented simple functions in Matlab programming to derive these parameters. Our concluding Matlab program is as good as calculator, and the output is visualized by plotting function.

Presented is an SU-8 microcantilever sensor with integrated piezoresistors made of a mixture of SU-8 polymer and silver nanoparticles. The resulting composite is a spin-coatable and ultraviolet patternable conductive polymer, which can be easily incorporated with any SU-8-based microdevice. The microfabrication technique used in this work is based on adhesive bonding of the cantilever layers with the thick support base to obtain a three-dimensional structures device, which is a cost-effective and fast fabrication process. Based on the current-voltage ( I - V ) test, the fabricated piezoresistors exhibit a linear resistance characteristic with good conductivity. The gauge factor calculated from the deflection test was obtained to be as high as 26.3, demonstrating the capability for embedded SU-8/Ag piezoresistors to improve sensitivity when using polymeric material as a sensor platform.

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Over the years, new discoveries have led to new applications, often taking advantage of their unique electrical properties, extraordinary strength and efficiency in heat conduction. Since industrialisation, human activities have resulted in steadily increasing concentrations of the greenhouse gases. Excess amount of carbon dioxide (CO2) in living environment is toxic and unsuitable for human consumption. Thus, a need exists for accurate, inexpensive, long-term monitoring of environmental contaminants using sensors that can be operated on site. Over the past decade, many wireless sensor network (WSN)-based monitoring applications have been proposed. This article reviews the developments of sensing elements to monitor CO2 in the environment. The cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science,...

Despite its excellent performance in microelectronic industry, silicon was not able to perform well in photonic devices arena. This is because the silicon has never been a good optical source mainly due to its indirect band gap structure. Many of the device functionalities in silicon have been reported, with an exception of – until recently – a reliable optical source. Silicon is a nonlinear material which makes use of its nonlinearities to realize various functionalities. This paper presents a theoretical treatment of generating and enhancing third-harmonic field which may be used as optical source, crystal state monitoring and all-optical signal processing applications.

The current paper presents an improved bandgap voltage reference (BGR) that utilizes curvature-corrected current generators which compensate for the voltage reference at lower and higher temperature range. The voltage reference is operated with a supply voltage of 2.5V to achieve an output reference of 1.1835V. The temperature coefficient achieved from the circuit is 1.342ppm/°C, resulting from temperature changes between -50°C to 125°C, sixfold improvement from first-order BGR. The proposed circuit is simulated using Silterra 0.13µm CMOS technology.

In the current paper, an improvement of piecewise curvature-corrected CMOS bandgap reference (BGR) circuit is proposed. The circuit utilizes piecewise nonlinear curvature-corrected current (PNCCC) in a conventional BGR with a current control circuit, which compensates for the voltage reference at a higher temperature range. The current control circuit (CCC) is used to reduce the total current at low temperature when the PNCCC generator is inactive. The proposed circuit is realized in CMOS 0.13µm and has been verified to be able to save power consumption by 18.6% compared with a circuit without the current control circuit.

This paper reports a general on-wafer noise figure (NF) de-embedding technique with the analysis of two gain definitions. As implemented in this work, all elements involved in NF measurement were determined and classified as a multi-stage network, and the well-known Friis law is applied to correct the noise contributions coming from other stages. With the two gain definitions, the effects of impedance match on NF are investigated. The result shows an NF of 3.80dB obtained with the de-embedding method and 6.06dB without the de-embedding method. This result is for vector measurement using the available gain, which gives 0.18dB improvement in NF as opposed to scalar measurement utilizing the insertion gain. Furthermore, NF was also measured at 5.63dB, 5.76dB, and 4.75dB under three different source impedances, namely, short, open, and load, respectively.

This paper presents the construction of large girth Quasi-Cyclic low density parity check (QC-LDPC) codes and a new multicarrier frequency hopping spread spectrum (MCFH-SS) system. The performance of newly obtained codes is evaluated by comparing with Reed Solomon (RS) codes. The computer simulation results show that the two girth-twelve QC-LDPC codes significantly outperform conventional RS codes with a gain of 2.1 dB at

Silicon or glass was a common material for SU8 coating. However, these materials are hard and brittle, make it difficult for drilling and dicing. This paper reported the effect of grayscale and resolution based on the various length of time for Propylene Glycol Methyl Ether Acetate (PGMEA) developing towards SU8-10 coated on polymethylmethacrylate (PMMA). The grayscale results show that the 0% (solid black) produced the highest percentage on the square structure formed to the SU8-10 film coated on PMMA and the highest resolution had been produced for the 30 minutes of PGMEA developing.

Frequency hopping spread spectrum with noncoherent M-ary frequency shift keying system is considered. In this study Reed Solomon codes RS (255, 223) are employed in a standard error correction role to provide some Anti-Jamming (AJ) capability with 8-bit symbols. Noise has been added to RS encoded data, which is demodulated at RS decoder perfectly. Matlab simulations have been implemented for numerical results. Graphical results have been plotted between the probability of an erasure versus ρ using RS (255, 223) code for 1 and 2 kHz frequencies. The simulation results have proved that system having RS (255, 223) code with M = 32 require substantially less signal to jammer power ratio to achieve the same bit error probability.

This paper presents the design of five-stage current controlled inductor-less ring oscillator that were simulated in Silterra 0.18um CMOS Technology with oscillation frequencies up to 5.99 GHz. The design uses cross coupled MOS devices along with active inductor (thus inductorless) and controlled by current source to aid in switching speed and to improve the noise parameters. The simulations show that the five-stage oscillator achieves frequency in the range of 3.78GHz to 5.99GHz. The simulated phase noise of the same design was -115.67 dBc/Hz at 1MHz offset with a center frequency of 5.99GHz.

This study presents the behavior of a micro cantilever beam accelerometer under electrostatic actuation by using the analytical and numerical method. The objective of this study is to determine optimal design of capacitive micro cantilever beam accelerometer in term of reducing the beam deflection with respect to applied acceleration but keeping the distance between electrodes. The structure contains proof mass which is suspended between fixed rigid electrodes to provide differential capacitance measurements. ANSYSO is used for finite element analysis (FEA) modeling and simulation. The analytical modeling is done by using C programming. Three dimensional modeling is done for six different loading conditions in order to come out with the optimal design. The results obtained from both the analytical and finite element models are found to be in excellent agreement.

Attitude determination system (ADS) was indispensable in attitude control of satellite. Especially for InnoSAT due to the limitation of budget, weight, and power, the attitude was determined using onboard position sensors. Previous research has successfully implemented the attitude determination using only Earth's magnetic field sensors for small attitude angle, but the approach produced quite big error for large attitude angle. This paper presents attitude determination for InnoSAT using combination of sun sensors and earth's magnetic field for large attitude angle. The attitude was determined using a deterministic (QUEST) and recursive (EKF) approach. A problem arises when using the sun sensors while the satellite experiencing eclipse. Consequently, the accuracy of both approaches was analyzed at eclipse and no eclipse conditions. The result shows that deterministic approach produced better accuracy at no eclipse but recursive approach produced better accuracy at eclipse. The strategy to apply the both approaches and eclipse conditions also discussed in this paper.

This work studied the flow behaviour of microfluidic-based acoustic sensor at a region where the flow of fluid was considered to be significant in determining the overall flow behaviour of the system flow in microchannel. The study was carried out based on finite element model (FEM) using ANSYS multiphysics package. Two structural parameters, reservoir or chamber height and the number of microchannel were used as the varying parameter. The flow behaviour was then analysed based on pressure distribution, velocity contour and velocity vector for a single and dual microchannel configuration with different reservoir height. The height was varied in the range of 20 to 100 μm due to limitation in the thickness of mold material during fabrication. Simulation results reveal that the flow response was not critically affected by the chamber height, whereas the dual microchannel configuration had an approximately a factor of 2.8 higher in terms of its flow velocity compared to the single microchannel configuration. This effect was referred as an amplification factor of the flow response due to this structure variation.