Open Access. Powered by Scholars. Published by Universities.®

Electrical and Computer Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles

Discipline
Institution
Keyword
Publication Year

Articles 421 - 450 of 564

Full-Text Articles in Electrical and Computer Engineering

Strain Sensor Based On A Pair Of Single-Mode-Multimode-Single-Mode Fiber Structures In A Ratiometric Power Measurement Scheme, Agus Hatta, Yuliya Semenova, Qiang Wu, Gerald Farrell Jan 2010

Strain Sensor Based On A Pair Of Single-Mode-Multimode-Single-Mode Fiber Structures In A Ratiometric Power Measurement Scheme, Agus Hatta, Yuliya Semenova, Qiang Wu, Gerald Farrell

Articles

The strain and temperature dependencies of a step-index single-mode–multimode–single-mode (SMS) fiber structure are investigated numerically and experimentally. For intensity-based strain measurement using a single SMS fiber structure, at a selected wavelength, it is found that there is a high strain dependence, but also a temperature dependence that will induce strain measurement error. To minimize the temperature-induced strain measurement error, two SMS fiber structures are proposed and demonstrated in a ratiometric power measurement scheme; one SMS structure acts as the strain sensor, and the other SMS structure acts as the temperature monitor. The extracted temperature information is used to determine a …


A Study Of The Effect Of The Position Of An Edge Filter Within A Ratiometric Wavelength Measurement System, Qiang Wu, Pengfei Wang, Yuliya Semenova, Gerald Farrell Jan 2010

A Study Of The Effect Of The Position Of An Edge Filter Within A Ratiometric Wavelength Measurement System, Qiang Wu, Pengfei Wang, Yuliya Semenova, Gerald Farrell

Articles

The effect of the position of an edge filter within a ratiometric wavelength measurement system was investigated based on three cases: (1) the reflected fibre Bragg grating (FBG) signal passes through both the reference arm and the edge filter arm, (2) the reflected FBG signal is connected directly to the edge filter arm and does not pass through the reference arm, (3) the edge filter sits in line with the FBG and thus the source power is filtered prior to reaching the FBG. Both numerical simulations and experimental results show that cases 1 and 2 have similar system performance whilst …


Electron-Electron Scattering In A Double Quantum Dot: Effective Mass Approach, S. Yu. Kruchinin, A. V. Federov, A. V. Baranov, Tatiana Perova, Kevin Berwick Jan 2010

Electron-Electron Scattering In A Double Quantum Dot: Effective Mass Approach, S. Yu. Kruchinin, A. V. Federov, A. V. Baranov, Tatiana Perova, Kevin Berwick

Articles

We present a theoretical description of the first-order scattering of interacting electrons and holes in a double quantum dot. Assuming infinitely high walls, strong confinement, and a two-band approximation, we derive general expressions for the two-particle matrix elements of the screened Coulomb potential. We also determine the selection rules for different scattering channels and consider special cases where the corresponding matrix elements can be represented by simple analytical expressions. Numerical calculations of the matrix elements and an analysis of their dependence on the geometrical and material parameters of the double quantum dot have also been performed.


A Voltage Sensor Based On A Singlemode-Multimode-Singlemode Fiber Structure, Agus Hatta, Yuliya Semenova, Ginu Rajan, Gerald Farrell Jan 2010

A Voltage Sensor Based On A Singlemode-Multimode-Singlemode Fiber Structure, Agus Hatta, Yuliya Semenova, Ginu Rajan, Gerald Farrell

Articles

A voltage sensor based on a singlemode-multimodesinglemode (SMS) fiber structure, attached to a piezoelectric (PZT), utilized in a ratiometric optical power measurement scheme is proposed. The elongation of the PZT due to an applied voltage induces a strain on the SMS fiber structure and in turn results in a change in the transmission loss response of the SMS fiber structure. It is found that at selected wavelengths, a strong voltage dependence for the transmission loss of the SMS fiber structure can be achieved. The voltage information can be obtained from the power ratio of the system, assuming the system is …


Single Channel Vocal Separation Using Median Filtering And Factorisation Techniques, Derry Fitzgerald, Mikel Gainza Jan 2010

Single Channel Vocal Separation Using Median Filtering And Factorisation Techniques, Derry Fitzgerald, Mikel Gainza

Articles

This paper deals with the problem of the extraction of vocals from single channel audio signals containing both vocals and other instruments, including both pitched instruments and percussion instruments. A novel median filtering-based approach for the extraction of vocal tracks is described, which is simple and efficient to implement. Further improvements in separation quality are then obtained by the application of tensor factorisation techniques to further extract residual instruments from the vocal mix. Finally, a novel use of non-negative partial matrix cofactorisation is demonstrated as a means of further improving separation quality. Here the original single channel mixture is partially …


Bent Sms Fiber Structure For Temperature Measurement, Qiang Wu, Yuliya Semenova, Agus Hatta, Pengfei Wang, Gerald Farrell Jan 2010

Bent Sms Fiber Structure For Temperature Measurement, Qiang Wu, Yuliya Semenova, Agus Hatta, Pengfei Wang, Gerald Farrell

Articles

We have proposed a temperature sensor fabricated using a bent SMS fiber structure. Our experimental results show, that by comparison to a sensor based on a straight SMS fiber structure, this temperature sensor has a much higher sensitivity of 31.97 pm/°C over a temperature range from 20 to 80 °C based on the measurement of the mean 3 dB wavelength shift and offers a resolution of 0.1 °C for temperature range from 45 to 80 °C when demodulated by a simple ratiometric interrogation technique.


Temperature Performance Of A Macrobending Single-Mode Fiber-Based Refractometer, Pengfei Wang, Yuliya Semenova, Qiang Wu, Zie Zheng, Gerald Farrell Jan 2010

Temperature Performance Of A Macrobending Single-Mode Fiber-Based Refractometer, Pengfei Wang, Yuliya Semenova, Qiang Wu, Zie Zheng, Gerald Farrell

Articles

The temperature dependence of polarization-dependent loss (PDL) for a macrobending standard single-mode fiber (SMF28) is investigated both theoretically and experimentally. The experimental results show an overall agreement with the proposed theoretical model over a temperature range from 0 C to 70 C. An SMF28-based edge filter is used as an example regarding temperature- dependent PDL performance. It is shown that the temperature variations have a significant influence on the polarization dependence of macrobending loss, and further impact on such a fiber bend loss edge filter used in a wavelength measurement application. It is also concluded that by using the proposed …


A Liquid Crystal Coated Tapered Photonic Crystal Fiber Interferometer, Ginu Rajan, Sunish Mathews, Gerald Farrell, Yuliya Semenova Jan 2010

A Liquid Crystal Coated Tapered Photonic Crystal Fiber Interferometer, Ginu Rajan, Sunish Mathews, Gerald Farrell, Yuliya Semenova

Articles

An experimental investigation on liquid crystal coated tapered photonic crystal fiber (PCF) interferometer is presented in this paper. The interferometer is fabricated by tapering a small section of a PCF by collapsing the air holes and thinning down the air hole collapsed region to a micron size. Several interferometers are fabricated from different types of photonic crystal fibers and the temperature dependence studies are carried out to select an intrinsically temperature insensitive interferometer that can be used with liquid crystal (LC) materials. The properties of the LC materials to be used with the tapered PCF interferometers are also discussed. Temperature …


Simulation Procedure For The Co-Optimization Of Photovoltaic Water Pumping Systems., Brian Norton Jan 2010

Simulation Procedure For The Co-Optimization Of Photovoltaic Water Pumping Systems., Brian Norton

Articles

Abstract: Photovoltaic (PV)-powered centrifugal water pumping systems have been modelled based on field experience and analysis of long-term measured performance of several installed PV-powered water pumping systems. This paper presents detailed modelling of a PV array, an inverter, a three-phase induction motor, a centrifugal pump, a well, a storage tank, an overflow controller, and an integrated reverse osmosis desalination unit. The component models were validated using both laboratory measurements and long-term monitored data. All system components have been modelled separately, and the system was modelled in TRNSYS. The models are capable of simulating grid-connected, diesel-powered, and PV-powered water pumping systems, …


Spontaneous Periodic Deformations In Nonchiral Planar-Aligned Bimesogens With A Nematic-Nematic Transition And A Negative Elastic Constant, V. P. Panov, J. K. Vij, Yuri Panarin, A. Kohlmeier, M. G. Tamba, R. A. Lewis, G. H. Mehl Jan 2010

Spontaneous Periodic Deformations In Nonchiral Planar-Aligned Bimesogens With A Nematic-Nematic Transition And A Negative Elastic Constant, V. P. Panov, J. K. Vij, Yuri Panarin, A. Kohlmeier, M. G. Tamba, R. A. Lewis, G. H. Mehl

Articles

Hydrocarbon linked mesogenic dimers are found to exhibit an additional nematic phase below the conventional uniaxial nematic phase as confirmed by x-ray diffraction. The phase produces unusual periodic stripe domains in planar cells. The stripes are found to be parallel to the rubbing direction (in rubbed cells) with a well-defined period equal to double the cell gap. The stripes appear without external electromagnetic field, temperature or thickness gradients, rubbing or hybrid alignment treatments. Simple modeling proposes a negative sign for at least one of the two elastic constants: splay and twist, as a necessary condition for the observed pattern.


Protection Of Upqc Against The Load Side Short Circuits, Iurie Axente, Malabika Basu, Michael Conlon, Kevin Gaughan Jan 2010

Protection Of Upqc Against The Load Side Short Circuits, Iurie Axente, Malabika Basu, Michael Conlon, Kevin Gaughan

Articles

This study presents a protection scheme for protecting the series inverter of a unified power quality conditioner (UPQC). The proposed scheme protects the series inverter from overcurrents and overvoltages, which appear during short-circuit faults on the load side of the UPQC. The main protection element is a crowbar connected across the secondary of the series transformer and consists of a pair of antiparallel connected thyristors, which is governed by a simple Zener diode-based control circuit. In the case of an overvoltage, the crowbar short circuits the secondary of the transformer, thus removing the overvoltage and diverting the fault current from …


Liquid Crystal Display Modes In A Nontilted Bent-Core Biaxial Smectic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, J. K. Vij, C. Keith, C. Tschierske Jan 2010

Liquid Crystal Display Modes In A Nontilted Bent-Core Biaxial Smectic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, J. K. Vij, C. Keith, C. Tschierske

Articles

Liquid crystal display (LCD) modes associated with the rotation of the secondary director in nontilted, biaxial smectic phase of an achiral bent-core compound are demonstrated. For LCDs, we find that at least four display modes are possible using SmAPA phase of the studied material, in which the minor directors in adjacent layers are aligned antiferroelectrically. The advantages of these modes include low driving field (1–2 V/ µm), high contrast ratio 1000:1, relatively fast switching time of 0.5 ms and continuous gray scale. The molecular short axis or the polar axis in a negative dielectric, biaxial material is oriented by the …


Electric Field Induced Biaxiality And The Electro-Optic Effect In A Bent-Core Nematic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, U. Manna, J. K. Vij, C. Keith, C. Tschierske Jan 2010

Electric Field Induced Biaxiality And The Electro-Optic Effect In A Bent-Core Nematic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, U. Manna, J. K. Vij, C. Keith, C. Tschierske

Articles

We report the observation of a biaxial nematic phase in a bent-core molecular system using polarizing microscopy, electro-optics, and dielectric spectroscopy, where we find that the biaxiality exists on a microscopic scale. An application of electric field induces a macroscopic biaxiality and in consequence gives rise to electro-optic switching. This electro-optic effect shows significant potential in applications for displays due to its fast high-contrast response. The observed electro-optic switching is explained in terms of the interaction of the ferroelectric clusters with the electric field. © 2010 American Institute of Physics.


Influence Of Solar Heating On The Performance Of Integrated Solar Cell Microstrip Patch Antennas, Maria Roo Ons, S. Shynu, M Seredynski, Max Ammann, Sarah Mccormack, Brian Norton Sep 2009

Influence Of Solar Heating On The Performance Of Integrated Solar Cell Microstrip Patch Antennas, Maria Roo Ons, S. Shynu, M Seredynski, Max Ammann, Sarah Mccormack, Brian Norton

Articles

The integration of microstrip patch antennas with photovoltaics has been proposed for applications in autonomous wireless communication systems located on building façades. Full integration was achieved using polycrystalline silicon solar cells as both antenna ground plane and direct current power generation in the same device. An overview of the proposed photovoltaic antenna designs is provided and the variation characterised of the electromagnetic properties of the device with temperature and solar radiation. Measurements for both copper and solar antennas are reported on three different commercial laminates with contrasting values for thermal coefficient of the dielectric constant.


Directional Dual-Band Slot Antenna With Dual-Bandgap High-Impedance-Surface Reflector, Xiulong Bao, Giuseppe Ruvio, Max Ammann Sep 2009

Directional Dual-Band Slot Antenna With Dual-Bandgap High-Impedance-Surface Reflector, Xiulong Bao, Giuseppe Ruvio, Max Ammann

Articles

A compact dual-band high-impedance-surface EBG structure is employed as a reflector for a dual-band annular-slot antenna. The reflector comprises an array of miniaturized EBG cells which utilizes square patches augmented by four S-shaped corrugated arms to reduce the resonant frequency of the proposed EBG structure. In order to broaden the bandwidth and adjust the frequency ratio for the dual-band EBG structure, a log-periodic spacing between the S-shaped strips is introduced. The combination of microstrip-fed annular slot and EBG reflector provides directional properties for both frequency bands with reduced size and low-profile.


Temperature Induced Instabilities In Macro-Bend Fiber Based Wavelength Measurement Systems, Ginu Rajan, Yuliya Semenova, Pengfei Wang, Gerald Farrell May 2009

Temperature Induced Instabilities In Macro-Bend Fiber Based Wavelength Measurement Systems, Ginu Rajan, Yuliya Semenova, Pengfei Wang, Gerald Farrell

Articles

An investigation of temperature-induced instabilities in a wavelength measurement system based on macro-bend fiber filter used in the ratiometric scheme are presented. Two wavelength measurement systems based on macro-bend fiber, a standard low bend loss single-mode fiber filter based system and a high bend loss fiber filter based system are considered. In the case of a low bend loss fiber filter based system, the oscillatory variation in the ratio response with temperature and the difference in the temperature-induced ratio variation at different wavelengths makes the temperature corrected calibration of the system unfeasible, which is essential for precise wavelength measurements. The …


A Macrobending Singlemode Fiber Based Refractometer, Pengfei Wang, Yuliya Semenova, Qiang Wu, Gerald Farrell, Yungqiang Ti, Jie Zheng Jan 2009

A Macrobending Singlemode Fiber Based Refractometer, Pengfei Wang, Yuliya Semenova, Qiang Wu, Gerald Farrell, Yungqiang Ti, Jie Zheng

Articles

A novel macrobending based all-fiber refractometer sensor with a simple optical configuration is proposed and investigated both theoretically and experimentally. The proposed fiber refractometer sensor consists of a single loop structure of bare macrobending standard singlemode fiber (SMF28) with a selected bending radius and reduced cladding diameter. The well-known scalar approximation theory is employed to theoretically predict the characteristics of the proposed fiber refractometer sensor. An approach to improve the resolution of the refractometer is presented, which shows that the refractometer with a reduced cladding diameter of 81 μm has an experimentally verified resolution of 5.75105 for a refractive index …


Analysis And Performance Evaluation Of An All-Fiber Wide Range Interrogation System For A Bragg Grating Sensor Array, Ginu Rajan, Yuliya Semenova, Gerald Farrell Jan 2009

Analysis And Performance Evaluation Of An All-Fiber Wide Range Interrogation System For A Bragg Grating Sensor Array, Ginu Rajan, Yuliya Semenova, Gerald Farrell

Articles

Analysis and performance evaluation of a macro-bend ¯ber based interrogation system for a Bragg grating sensor array is presented. Due to the characteristic properties of the macro-bend ¯ber ¯lter such as polarization and temperature dependence and the total noise associated with the ratiometric system, a best ¯t ratio slope is required to interrogate multiple FBGs whose peak wavelengths are spread over a wide wavelength range, rather than the optimal slope for individual FBG. In this paper for investigation we have used an FBG array with 5 FBGs with peak re°ected wavelengths lying between 1525 nm and 1575 nm. The analysis …


Electronic Tunability Of Ferroelectric Liquid Crystal Infiltrated Photonic Crystal Fibre, Sunish Mathews, Yuliya Semenova, Gerald Farrell Jan 2009

Electronic Tunability Of Ferroelectric Liquid Crystal Infiltrated Photonic Crystal Fibre, Sunish Mathews, Yuliya Semenova, Gerald Farrell

Articles

The electronic tunability of ferroelectric liquid crystal filled photonic crystal fibres is demonstrated for the first time. The tunability is obtained in the wavelength range of 1500 -1600 nm, with a free spectral range of ~ 20 nm. The electronic tunability is achieved by applying an electric field onto the infiltrated photonic crystal fibre which facilitates the photonic bandgap tuning owing to the microsecond order switching speeds of Ferroelectric Liquid crystals. The polarized transmission spectrum shows the behavior of a tunable notch filter with a change in applied voltage. The results obtained could pave the way for the fabrication of …


Sms Fibre Structure For Temperature Measurement Using A Simple Intensity-Based Interrogation System, Agus Hatta, Ginu Rajan, Yuliya Semenova, Gerald Farrell Jan 2009

Sms Fibre Structure For Temperature Measurement Using A Simple Intensity-Based Interrogation System, Agus Hatta, Ginu Rajan, Yuliya Semenova, Gerald Farrell

Articles

A singlemode–multimode–singlemode (SMS) fibre structure for temperature measurement that utilises a simple intensity-based interrogation system is proposed. The temperature dependence of the SMS fibre structure utilised as a sensor is investigated numerically and experimentally. It is found that a strong temperature dependence for the SMS fibre structure exists at selected wavelengths. The temperature characteristic at such wavelengths is linear in nature and can be used for temperature measurements. The proposed temperature sensor offers a high resolution and accuracy, and also benefits from a simple configuration and low cost when compared to other fibre-optic temperature sensors.


High Resolution Temperature Insensitive Interrogation Technique For Fbg Sensors, Qiang Wu, Yuliya Semenova, An Sun, Pengfei Wang, Gerald Farrell Jan 2009

High Resolution Temperature Insensitive Interrogation Technique For Fbg Sensors, Qiang Wu, Yuliya Semenova, An Sun, Pengfei Wang, Gerald Farrell

Articles

In this letter, we propose a high resolution temperature insensitive interrogation technique for FBG sensors where one FBG acts as an edge filter to interrogate a separate FBG sensor. A high resolution of better than 5 με in strain measurement range from 0 to 1100 με and the best resolution of better than 1 με were verified by experiments. An error of only ±2.2 με is achieved over a temperature range from 15 to 50 °C, indicating that this strain interrogation technique is temperature insensitive. Using an altered system configuration, the temperature was also measured simultaneously with a resolution better …


Analysis Of Temperature Dependence For A Ratiometric Wavelength Measurement System Using Sms Fiber Structure Based Edged Filters, Agus Hatta, Yuliya Semenova, Ginu Rajan, Pengfei Wang, J. Zheng, Gerald Farrell Jan 2009

Analysis Of Temperature Dependence For A Ratiometric Wavelength Measurement System Using Sms Fiber Structure Based Edged Filters, Agus Hatta, Yuliya Semenova, Ginu Rajan, Pengfei Wang, J. Zheng, Gerald Farrell

Articles

Temperature dependence of an edge filter based on singlemode-multimodesinglemode (SMS) fiber structure is investigated numerically and experimentally. The experimental results and numerical results are in good agreement within an operational temperature range from 10 to 40 oC. It is found that the thermo-optic coefficient (TOC) has a more significant effect on the temperature dependence of an SMS edge filter compared to the thermal expansion coefficient (TEC). In the ratiometric wavelength measurement using two SMS edge filters, a small temperature variation can induce the ratio variation and in turn the wavelength measurement error. It is found the SMS edge filter’s response …


Rating Requirements Of The Upqc To Integrate The Fsig Type Wind Generation To The Grid, N. Jayanti, Malabika Basu, Michael Conlon, Kevin Gaughan Jan 2009

Rating Requirements Of The Upqc To Integrate The Fsig Type Wind Generation To The Grid, N. Jayanti, Malabika Basu, Michael Conlon, Kevin Gaughan

Articles

The ability of wind generation to remain connected to the grid in the event of system faults and dynamic reactive power compensation are two aspects of grid integration, which have received particular attention. The wind driven, fixed-speed induction generator (FSIG) on its own fails to fulfil these requirements of grid integration. The application of a unified power quality conditioner (UPQC) to overcome the grid integration problems of the FSIG is investigated. The role of the UPQC in enhancing the fault ride-through capability of the generator is also investigated under both full and partial terminal voltage restoration. A realistic estimation of …


Digital Camera Photographing In Measuring Propagation Loss Properties Of Ion2exchange Planar Optical Waveguides, Ling-Hua Jia, Feng Qiu, Jian Ying, Ti Yun-Jiang, Jie Z|Heng, Pengfei Wang, Gerald Farrell Jan 2009

Digital Camera Photographing In Measuring Propagation Loss Properties Of Ion2exchange Planar Optical Waveguides, Ling-Hua Jia, Feng Qiu, Jian Ying, Ti Yun-Jiang, Jie Z|Heng, Pengfei Wang, Gerald Farrell

Articles

The digital photographs of propagation lines of ion-exchange planar glass optical waveguides were taken by a common digital camera.According to the profile of light intensity of propagation lines,the attenuation curves were fitted and the propagation losses of the waveguides were calculated.The waveguides were treated by annealing process,and propagation losses properties were studied before and after annealing,respectively.The results show that the loss of waveguide increases with the mode.The loss in 0 mode decreases from 2.148 9 dB·cm-1 to 0.746 0 dB·cm-1.


Misalignment Limits For A Singlemode-Multimode-Singlemode Fiber-Based Edge Filter, Agus Hatta, Gerald Farrell, Pengfei Wang, Ginu Rajan, Yuliya Semenova Jan 2009

Misalignment Limits For A Singlemode-Multimode-Singlemode Fiber-Based Edge Filter, Agus Hatta, Gerald Farrell, Pengfei Wang, Ginu Rajan, Yuliya Semenova

Articles

Misalignment effects on the spectral characteristics of edge filters based on singlemode–multimode–singlemode (SMS) fibre structures are investigated numerically and experimentally. A modal propagation analysis is used with a set of guided modes calculated using the finite-difference method to determine the transmission loss of the SMS-based edge filters. A limit for the tolerable misalignment of the SMS fiber-based edge filter is proposed, beyond which the spectral performance of the SMS structure degrades unacceptably. The numerical results are verified experimentally with good agreement.


Emitter-Wrap-Through Photovoltaic Dipole Antenna With Solar Concentrator, Maria Roo Ons, S. Shynu, Max Ammann, Sarah Mccormack, Brian Norton Jan 2009

Emitter-Wrap-Through Photovoltaic Dipole Antenna With Solar Concentrator, Maria Roo Ons, S. Shynu, Max Ammann, Sarah Mccormack, Brian Norton

Articles

A novel photovoltaic dipole antenna employing a solar concentrator as a reflector is proposed. Four identical emitter-wrap-through rear contact solar cells connected in series as a folded dipole are simultaneously used for power generation and as the antenna radiating element, which is located in the focal line of a parabolic solar concentrator. The parabolic structure acts as a solar concentrator for the photovoltaic cells as well as a reflector for the folded dipole antenna. Full-wave electromagnetic simulation with supportive experimental work validates this design. The measured fractional impedance bandwidth and gain were 21% and 11.1 dBi, respectively. The antenna/solar arrangement …


Antenna Optimization With A Computationally Efficient Multiobjective Evolutionary Algorithm, Matthias John, Max Ammann Jan 2009

Antenna Optimization With A Computationally Efficient Multiobjective Evolutionary Algorithm, Matthias John, Max Ammann

Articles

An efficient multiobjective evolutionary algorithm is described for optimizing a novel spline based printed monopole antenna. The antenna geometry is based on spline outlines. Both radiating element and groundplane are simultaneously optimized by the algorithm. The resulting antenna performance is evaluated. It is shown that the evolutionary algorithm and the spline geometry can be used to efficiently generate ultrawideband antennas on limited computing resources.


Microstrip-Fed Dual-Frequency Annular-Slot Antenna Loaded By Split-Ring-Slot, Xiulong Bao, Max Ammann Jan 2009

Microstrip-Fed Dual-Frequency Annular-Slot Antenna Loaded By Split-Ring-Slot, Xiulong Bao, Max Ammann

Articles

A compact dual-band annular-slot antenna loaded by a concentric split-ring-slot is presented. A stepped microstrip feedline enables the control of the coupling and provides good matching. The annular-slot is connected to the split-ring-slot by a rectangular slot, which increases the surface of the current path, thus notably reducing the resonant frequency for a given size. The embedded split-ring-slot structure allows many resonant modes to be realised. By tuning the key parameters, these operating modes and their bandwidths can be controlled. A wide bandwidth can be realised for either the lower band, upper band or both bands simultaneously, depending on the …


Generalised Design Process For Fiber-Bend-Loss-Based Edge Filters For A Wavelength Measurement System, Pengfei Wang, Gerald Farrell, Yuliya Semenova Jan 2009

Generalised Design Process For Fiber-Bend-Loss-Based Edge Filters For A Wavelength Measurement System, Pengfei Wang, Gerald Farrell, Yuliya Semenova

Articles

We investigate and present a generalized methodology for the design of a fiber-bend-loss-based edge filter, starting with the task of evaluating and selecting suitable fibers and then considering the design of a fiber-bending-loss edge filter. As an example to illustrate the methodology, a Corning SMF28e fiber with a 900 μmdiameter is selected and two sample edge filters are designed for experimental verification. The designed edge filters are compact, easy to fabricate, meet target spectral specifications, and show low polarization-dependent loss, confirming the effectiveness of the proposed methodology for fiber-bend-loss-based edge filter design.


Use Of A Single-Multiple-Single-Mode Fiber Filter For Interrogating Fiber Bragg Grating Strain Sensors With Dynamic Temperature Compensation, Qiang Wu, Muhammad Hatta, Yuliya Semenova, Gerald Farrell Jan 2009

Use Of A Single-Multiple-Single-Mode Fiber Filter For Interrogating Fiber Bragg Grating Strain Sensors With Dynamic Temperature Compensation, Qiang Wu, Muhammad Hatta, Yuliya Semenova, Gerald Farrell

Articles

An interrogation technique for fiber Bragg grating (FBG) strain sensors with dynamic temperature compensation using a single-multiple-single-mode (SMS) fiber filter as a temperature compensating element is presented. Experimental results show that this technique offers a resolution of better than 3:4 με for strain measurements in the range from 0 to 1667 με, and the temperature induced error is as low as 34 με in the temperature range from 10 to 60 °C. The temperature induced error could be further reduced if the temperature sensitivity (the rate of temperature induced wavelength shift) of the SMS filter was closer to that of …