S. Malarvizhi

Design Analysis of MEMS Capacitive Differential Pressure Sensor for Aircraft Altimeter

In this paper, an analytical and simulation solution for Microelectromechanical systems (MEMS) based capacitive differential pressure sensor for aircraft altimeter is proposed. The principle and design of the proposed MEMS capacitive differential pressure sensor design is explained. Centre deflection and capacitive sensitivity analysis is carried out for circular, square and rectangle diaphragm membrane. Numerical analysis and simulation on deflection and capacitive sensitivity is carried out for the range of pressure from 100mbar to1100mbar. Gold, silicon and Liquid crystal polymer (LCP) material are selected as diaphragm membrane. Analysis and simulation result shows, that gold diaphragm membrane was more suitable for aircraft altimeter applications.

Simulation Analysis of MEMS Based Capacitive Differential Pressure Sensor for Aircraft Application

In this paper, simulation solution for Microelectromechanical systems (MEMS) based capacitive differential pressure sensor for aircraft altimeter is proposed. The principle of proposed MEMS capacitive differential pressure sensor design was explained. Analysis for the measurement of center deflection and capacitive sensitivity square diaphragm membrane was done. Simulation on deflection and capacitive sensitivity was carried out for the range of pressure from 100mbar to1100mbar. Gold, diaphragm membrane was used in this analysis. Analysis result shows, linear variation on center deflection and capacitance variation which is more suitable for this application.

Modeling of MEMS capacitive differential pressure sensor

In this paper, modeling of high sensitive capacitive differential pressure sensor (CDPS) structure was proposed. The-working principle of CDPS was explained. Different types of CDPS structure for aircraft altimeter were designed. Polymide square diaphragm membrane is used to sense the pressure. Simulation was carried out for the range of pressure from 116 mbar to 1100 mbar, which is equivalent to aircraft flying altitude. Analysis was done with simulation results for centre deflection sensitivity and capacitive sensitivity for different models of CDPS structure. From the simulated results an improved CDPS models with bossed diaphragm membrane shows linear characteristics. The deflection sensitivity and capacitive sensitivity are 10.912nm/mbar and 3.025fF/mbar respectively.

FPGA based pipelined architecture for RC5 encryption

The reconfigurable processors like FPGA are extensively used for cryptographic applications which have reduced the time to market of the hardware logic. This paper describes the high performance pipelined hardware implementation of RC5 algorithm in Xilinx Vertex II Pro FPGA with a 12-stage pipeline scheme that has achieved an encryption rate of 6.9 Gbps. The proposed design operates on 12 input data and a common key where each clock signal produces a partial single round encryption output. After 12 clocks cycles, the cipher text of the corresponding input data is derived at the output sequentially for every clock transition. The pipelined hardware was implemented and the efficiency was compared with the other versions of RC5.

Analysis of diffuse reflectance spectra of various skin conditions by principal component method

Different skin and sub-surface tissues have distinct or unique reflectance pattern which help us differentiate normal and cancerous tissues. Optical means of characterizing tissues have gained importance due to its noninvasive nature. Spectral characteristics of the components provide useful information to identify the components, because different chromophores have different spectroscopic responses to electromagnetic waves of a certain energy band.

Functional Optical Imaging of a tissue based on Diffuse Reflectance with Fibre Spectrometer

The functional state of tissue can influence its optical properties. Functional optical imaging capitalizes on the changing optical properties of tissue by using light to measure physiological changes. Optical Imaging i.e., medical imaging with light radiation is gaining importance especially for early detection of cancer.

An automated system for optical imaging to characterize tissue based on diffuse reflectance spectroscopy

More interest is shown towards optical technologies that have the capability of performing in situ tissue diagnosis without the need for tissue biopsy. The ability to non-invasively detect early disease is a boon to the patients as well as the medical professionals. In actuality, detection at the fully formed but not spreading stage is acceptable. We must see lesions as they are transforming from a pre-cancerous state to a cancerous state, to be successful at very early detection. Early diagnosis is of paramount importance to manage precancerous and malignant lesions. Discrimination between normal-tissue and new tissue formation relies on morphological and functional pattern recognition. The functional state of tissue can influence its optical properties. Functional optical imaging capitalizes on the changing optical properties of tissue by using light to measure physiological changes. The basis for this imaging method arise from the differences in the spectra obtained from the normal and diseased tissue owing to the multiple physiological changes associated with increased vasculature, cellularity, oxygen consumption and edema in tumour. An optical fiber spectrometer is set up for this purpose, which is safe, portable and very affordable relative to other imaging modalities. The method involves exposure of skin surface to white light produced by an incandescent source. The back scattered photons emerging from various layers of tissue are detected by spectrometer resulting in tissue surface emission profile. Initially, the study is conducted on tissue equivalent phantoms The spectral data from the scan is processed using a suitable algorithm to form an image which can directly assist us in differentiating the part which is affected by disease visually. The unique information obtained from the diffuse optical spectroscopy makes it suitable for a variety of clinical applications, such as therapeutic monitoring, lesion characterization and risk assessment.

FPGA based sliding window architecture for RC5 encryption

In the current scenario, security for the data has more of its concern. Many encryption algorithms have been proposed to satisfy certain levels of security issues and known for their cryptographic strengths. The extensive use of reconfigurable processors like FPGA for cryptographic applications has made the design and testing of hardware logic simple. This paper introduces, a new sliding window based hardware architecture in Xilinx FPGA for RC5 cryptographic algorithm modeled to satisfy the response and waiting time. This is done to provide faster encryption thereby reducing the risk of deadline miss. The performance comparison between implementation of various RC5 architectures based on area and delay are graphed.

Low Power Low Noise Tunable Active Inductor for Narrow Band LNA Design

paper presents a low power, low noise and high quality factor tunable single ended active inductor suitable for designing multiband RF front end circuits. The active inductor circuit uses differential configuration as positive transconductor and PMOS cascode structure as negative transconductor of a gyrator to reduce the noise voltage. It uses MOS transistor as a feedback resistor to provide possible negative resistance to reduce the inductor loss to enhance the quality factor. Also this structure provides wide inductive bandwidth and high resonance frequency. The tuning of center frequency and quality factor for multiband operation is achieved through the controllable current source. The center frequency tuning range of the active inductor varies from 3.9 GHz to 12.3 GHz. The designed active inductor and LNA are simulated in 180nm CMOS process using HSPICE simulation tool. Simulation results of the active inductor shows an inductive bandwidth varies from 6.45 MHz to 6.3 GHz with the center frequency 6.3 GHz. The inductance value ranges from 5nH to 550nH respectively. It has the less noise voltage of 12nV/√Hz to 5.6nV/√Hz for the designed tuning range and consumes less power of 0.65mW. The Low noise amplifier achieves the gain of 19dB, low noise figure of 2.1dB and consumes low power of 4.2mW. Keywordsinductor, Quality factor, Centre frequency tuning, PMOS cascode pair, tuning range, MOS resistor, Multiband RF front end.

Analysis of spectroscopic diffuse reflectance plots for different skin conditions

Optical means of characterizing tissues have gained importance due to its noninvasive nature. Spectral characteris- tics of the components provide useful information to identify the components, because different chromophores have different spectroscopic responses to electromagnetic waves of a certain energy band. The purpose of this study is to determine whether visible/near-infrared diffuse reflectance spectroscopy can be used to non-invasively characterize skin diseases in vivo. An optical fiber spectrometer is set up for obtaining diffuse reflectance spectra. The method involves exposure of skin surface to white light produced by an incandescent source. The back scattered photons emerging from various layers of tissue are detected by spectrometer resulting in diffuse reflectance spectra. For the present study different skin conditions like - warts, vitiligo, thrombus (due to injury) and angioma are chosen. The spectral data obtained from the scan are plotted and compared. More or less, the shapes of the spectral curves for various skin conditions resemble. In order to characterize and differentiate different diseased state spectral analysis based on Ratio analysis, Students t-tests and difference plot are carried out. Based on the analysis the relative spectral intensity changes are quantified and the spectral shape changes are enhanced and more easily visualized on the spectral curves, thus assisting in differentiating the normal tissue from the one affected by disease.