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1
Content available Four channel optical demultiplexer based on L2 photonic crystal microcavity
Ammari Merzoug, Benmerkhi Ahlem, Bouchemat Mohamed
Optica Applicata
|
2022
|
Vol. 52, nr 4
613--625
EN
The wavelength demultiplexing is a particularly important function in integrated optics and can be realized using photonic crystals. The aim is to extract accurately the wavelengths in a data flux. In this work, we investigate a new topologies of wavelength demultiplexing based on two-dimensional photonic crystals constituted of dielectric rods spread in a square network. The studied demultiplexer is based on optical filters with optimized parameters in order to extract four different wavelengths in the vicinity of frequencies corresponding to communication windows. It was found that the crosstalk between the structure channels of the demultiplexer are in the range of –19.19 and – 44.1 dB and the channel spacing is equal to 0.96 nm. The simulation results presented in this paper are performed and analyzed using the FDTD method.
2
Content available Micromechanically Tunable Dielectric Rod Resonator
Savin Kostiantyn, Golubeva Irina, Kazmirenko Victor, Prokopenko Yuriy, Vandenbosch Guy A. E.
International Journal of Electronics and Telecommunications
|
2021
|
Vol. 67, No. 4
615--621
EN
A resonant frequency control method for dielectric rod resonators is discussed. A dielectric rod of cylindrical shape is placed inside a metal cavity. The bottom face of the dielectric rod is fixed at the metal base plate. Resonant frequency tuning is achieved by lifting the top metal plate above the dielectric rod upper face. The paper presents simulations using the mode matching technique and experimental study of this tunable resonator. Resonant frequency of the basic mode can be tuned by more than an octave with displacements of only tens of micrometres, which is in range of piezoactuators, MEMS, etc. A distinct feature of the proposed tuning technique is that the quality factor of the system does not degrade throughout the tuning range.
3
Content available Implementation of C-PolSK Modulation in FSO Network and Analysis of its Atmospheric Performance
Chattopadhyay Diptangshu, Bharti Manisha
Journal of Telecommunications and Information Technology
|
2019
|
nr 4
43--49
EN
Free Space Optical (FSO) communication is a quickly developing technology that is designed to handle high data rates while maintaining a good quality factor (Q-factor). Many novel techniques have been implemented to cope with atmospheric attenuating factors, such as fog and rain. Here, we have introduced circular polarization shift keying (C-PolSK) modulation to produce a stable and uniform light beam. The plane of polarized light keeps rotating along with the propagation vector, which helps reduce phase variations and cross-channel effects. C-PolSK provides higher penetrating power and attenuation resistance over linear polarization shift keying (L-PolSK). Two different C-PolSK models have been proposed and graphical comparisons, relying on such parameters as Q-factor, transmission distance and inputoutput power, have been made. The cases of moderate fog and rain attenuation are taken to verify the model’s efficiency. Polarized light is split into two orthogonal components and then modulated using the Mach-Zehnder modulator. One of the models also employs the principle of orthogonal differential phase shifting. Eye diagrams have been provided to verify the bit error rate (BER). The orthogonal differential phase shifted C-PolSK model proves to be the most suitable implementation prototype.
4
Content available Active Inductor with Feedback Resistor Based Voltage Controlled Oscillator Design for Wireless Applications
Faruqe Omar, Amin Md. Tawfiq
International Journal of Electronics and Telecommunications
|
2019
|
Vol. 65, No. 1
57--64
EN
This paper presents active inductor based VCO design for wireless applications based on analysis of active inductor models (Weng-Kuo Cascode active inductor & Liang Regular Cascode active inductor) with feedback resistor technique. Embedment of feedback resistor results in the increment of inductance as well as the quality factor whereas the values are 125.6@2.4GHz (Liang) and 98.7@3.4GHz (Weng- Kuo). The Weng-Kuo active inductor based VCO shows a tuning frequency of 1.765GHz ~2.430GHz (31.7%), while consuming a power of 2.60 mW and phase noise of -84.15 dBc/Hz@1MHz offset. On the other hand, Liang active inductor based VCO shows a frequency range of 1.897GHz ~2.522GHz (28.28%), while consuming a power of 1.40 mW and phase noise of -80.79 dBc/Hz@1MHz offset. Comparing Figure-of-Merit (FoM), power consumption, output power and stability in performance, designed active inductor based VCOs outperform with the state-of-the-art.
5
Content available remote Estimation of the quality factor based on the microseismicity recordings from Northern Poland
Wandycz Paweł, Święch Eryk, Eisner Leo, Pasternacki Andrzej, Wcisło Miłosz, Maćkowski Tomasz
Acta Geophysica
|
2019
|
Vol. 67, no. 6
2005--2014
EN
We use the peak frequency method to estimate effective P- and S-wave quality factors (QP and QS) based on the recorded waveforms of microseismic events. We analyze downhole datasets recorded during the hydraulic stimulation of the two unconventional gas reservoirs located in the northern part of Poland. The effective attenuation is lower in the deeper reservoir consistent with higher compaction. In both cases, we observe high QS values relative to QP which is consistent with attenuation coefficients of saturated reservoirs.
6
Content available Generating and modeling of braking curve and the assessment of the quality of automatic stopping of the train
Anuszczyk J., Gocek A., Pacholski K., Dominikowski B.
Transport Problems
|
2018
|
T. 13, z. 2
13--25
EN
This paper presents the theory about generating the braking curve and the analysis of the influence of the braking controller parameters on the generation of the braking curve of the train. In this paper, computed examples of braking quality developed using generic quality factor are shown, and on the basis of the calculations, weight components of the factor and an additional criterion for assessing the quality of braking were proposed. It has been demonstrated that the developed algorithms can be used to verify the effectiveness of the braking controller and the adjustment of the terms, and the change of these algorithms affects the shape of the generated braking curve of the train. It has been shown that the analysis of a failure of the propulsion car revealed the existence of a safe braking area. The performed statistical analysis confirmed the normal distribution of the scatter of braking results, for which the regression model fitted.
7
Content available remote Integrated 25 GHz and 50 GHz spectral line width dense wavelength division demultiplexer on single photonic crystal chip
Balaji V. R., Murugan M., Robinson S., Nakkeeran R.
Opto-Electronics Review
|
2018
|
Vol. 26, No. 4
285--295
EN
We propose a new integrated demultiplexer model using the two-dimensional photonic crystal (2D PC) through the hexagonal resonant cavity (HRC) for the International Telecommunication Union (ITU) standard. The integrated model of demultiplexer for both 25 GHz and 50 GHz has been designed for the first time. The demultiplexer consists of bus input waveguide, drop waveguide, Hexagonal Resonant Cavity (HRC), 6 Air Hole Filter (6-AHF), 7 Air Hole Filter (7-AHF). The 7-AHF is used to filter 25GHz wavelength, and the 6-AHF filter is used to filter 50 GHz wavelength. The Q-factor on the designed demultiplexer is flexible based on the idea of increasing the number of air holes between drop waveguide and resonant cavity. The demultiplexer is designed to drop maximum 8 resonant wavelengths. One side of demultiplexer is able to drop 50 GHz ITU standard wavelengths, which are of 1556.3 nm, 1556.7 nm, 1557.1 nm and 1557.5 nm, and further the other facet is able to drop 25 GHz wavelengths, which are of 1551.4 nm, 1551.6 nm, 1551.8 nm, and 1552.0 nm. The proposed demultiplexer may be carried out within the integrated dual system. This system is able to lessen the architecture cost and the size is miniaturized substantially.
8
Content available Channel drop filter based on photonic crystal ring resonator
Alipour-Banaei H., Jahanara M., Mehdizadeh F.
Optica Applicata
|
2018
|
Vol. 48, nr 4
601--608
EN
Photonic crystal ring resonators are promising candidates for realizing all optical filters with acceptable transmission efficiency and quality factor values. In this paper, by putting a hexagon-shaped structure at the middle of on 7 × 7 square cavity we created a ring resonator structure and designed a channel drop filter. The drop wavelength of our filter is at 1550.4 nm, with transmission efficiency and quality factor equal to 94% and 707, respectively. Our structure is composed of dielectric rods immersed in air. Because in this kind of structures the dominant band gap is in TM mode, all of our simulations have been done in TM mode. The total footprint of our filter is 199.4 μm2, which makes it suitable for all optical integrated circuits.
9
Content available remote Antena fraktalna – badanie wpływu stopnia iteracji drzewa fraktalnego na częstotliwości rezonansowe oraz dobroć anten
Malinowska M.
Zeszyty Naukowe Akademii Morskiej w Gdyni
|
2016
|
nr 95
54--65
PL
Dobroć anteny (Q) jest wygodnym parametrem, umożliwiającym porównywanie anten małych w stosunku do długości fali. W artykule zebrano najważniejsze informacje dotyczące tego parametru. Przedstawiono zależność szerokości pasma pracy anteny od dobroci, dolne ograniczenie dobroci (tzw. granicę Chu) oraz zależność dobroci od impedancji wejściowej anteny. Zwrócono uwagę na unikatowe właściwości anten fraktalnych. Przeprowadzono analizę symulacji impedancji promieniowania anten w postaci pierwszych pięciu iteracji drzewa fraktalnego oraz porównanie z ekwiwalentną anteną monopolową o długości równej badanym strukturom. Zastosowano omówioną koncepcję dobroci anteny do oceny przydatności anten z punktu widzenia szerokości pasma. Wskazano na obszary długości elektrycznych (ka) i numery iteracji, gdzie zastosowanie anteny fraktalnej o kształcie drzewa jest najbardziej korzystne. Pokazano też wpływ kolejnych iteracji na częstotliwości rezonansowe anten oraz ich wzajemne stosunki.
EN
The antenna quality factor (Q) is an useful parameter that allows to compare the antennas if the size of an antenna is small regarding the operating wavelength. The paper summarizes the most important information about the Q. The relationship between the Q and a bandwidth, the lower bound of the Q (Chu – limit) as well as the relationship between the Q and the input impedance have been presented. Also, some unique properties of the fractal antennas have been outlined. The paper also refers to the analysis of simulations of the fractal antennas radiation impedance. The geometry of tested antennas is based on the first five iterations of the fractal tree. The antenna analysis results with monopole of the same length have been compared. The idea of using the Q factor to compare the possible bandwidth of the antennas has been applied. As a results the area of the best electrical length ‘ka’ as well the proper iteration number has been shown. Also an influence of the iteration number on the antenna resonant frequencies has been presented.
10
Wyznaczanie rozdzielczości danych wejściowych w technice drukowania elektrofotograficznego
Markowski L., Przepiórka A.
Przegląd Papierniczy
|
2016
|
R. 72, nr 5
323--328
PL
Powtarzalność i dokładność to kluczowe elementy w procesie drukowania. W procedurach dotyczących przygotowania danych cyfrowych do druku stosuje się zwykle kryterium Nyquista. Stanowi ono, że obraz musi być próbkowany z częstotliwością dwa razy wyższą niż liniatura rastra, który będzie używany do drukowania. W praktyce rozdzielczość danych wejściowych jest często zaniżana, pomimo że współczesne urządzenia cyfrowe drukują już z liniaturami na poziomie 200 lpi. W prezentowanej pracy podjęto próbę wyznaczenia optymalnej rozdzielczości oryginałów przeznaczonych do reprodukcji w technice elektrofotograficznej z zastosowaniem wysokiej liniatury rastra. W tym celu opracowano obraz testowy, który został wydrukowany z wykorzystaniem dwóch urządzeń różnych producentów. Na podstawie oceny wizualnej wydruków określono zalecenia dotyczące przygotowania do drukowania prac, których reprodukcje wymagają wysokiej jakości. Wyniki badań wskazują, że właściwa reprodukcja oryginałów zawierających drobne detale wymaga podwyższenia standardowej rozdzielczości danych wejściowych z 300 do 400 ppi.
EN
Reproducibility and accuracy are key elements in the printing process. Established procedures for preparing digital data to printing are influenced by the Nyquist Criterion which states that an image must be sampled at twice the frequency of the line screen ruling that will be used to print the final image. In practice, the resolution of the input data is underestimated, although modern digital devices use screen ruling at level about 200 lpi. The purpose of this study was to determine the optimal resolution of digital originals for reproduction in electrophotography with using a high screen ruling. For this purpose special test was designed and printed using two devices from different manufacturers. Analysis of printouts show that reproduction of originals with high detail requires an increase of the input data from 300 ppi standard to 400 ppi.
11
Content available Improved low channel spacing high quality factor four-channel demultiplexer based on photonic crystal ring resonators
Talebzadeh R., Soroosh M., Mehdizadeh F.
Optica Applicata
|
2016
|
Vol. 46, nr 4
553--564
EN
In this paper, we propose a compact structure to realize the demultiplexing operation for dense wavelength division multiplexing communication systems using improved shell-type ring resonators in a photonic crystal structure. The cross-section of the structure is 790 μm2 and is desirable for integration based on popular planar technology. To improve power transmission coupling efficiency, we introduce the phase matching condition between ring resonators and waveguides; the results exhibit near 100% transmission efficiency. To obtain a high quality factor, we use interior lower refractive indices spheres inside the ring resonators as the mirrors; a quality factor as high as 15497 is achieved. The average pass bands of channels are near 0.1 nm, and the channel spacing is approximately 0.6 nm. The wavelengths of the demultiplexer are 1549, 1549.7, 1550.3 and 1550.9 nm. The crosstalk is between –14 and –29 dB, and the mean value of the crosstalk is –18.39 dB.
12
Content available Capacitor sensor impedance parameter measurement method for the degradation degree evaluation of hydraulic oil in the process of thermal oxidation
Umiński W.
Problemy Eksploatacji
|
2013
|
nr 3
147--158
EN
The paper describes a diagnostic method for the evaluation of the condition of hydraulic oil with the use of the dependence between oil degradation and changes in capacitor sensor impedance components. A series of new capacitive sensors has been developed, and impedance components measurements of hydraulic oil HL-46 laboratory oxidative degradation were conducted by means of microprocessor-based LCR meter. Preliminary laboratory measurement results have shown that equivalent series resistance ESR and quality factor Q of a capacitor series circuit model are most suitable for the evaluation of the condition of oil. The measurements indicated the best capacitive sensor sensitivity.
PL
W artykule przedstawiono metodę badawczą umożliwiającą ocenę zmian stanu oleju hydraulicznego w procesie termoutleniania poprzez pomiar za pomocą mikroprocesorowego miernika LCR, zmian parametrów impedancyjnych zastępczego układu szeregowego lub równoległego czujnika pojemnościowego (określanego również jako kondensator pomiarowy) zanurzonego w oleju. Opisano konstrukcję czujnika oraz zaprezentowano wybrane wyniki wstępnych pomiarów parametrów impedancyjnych dla różnych typów i rodzajów czujników dla próbek oleju hydraulicznego HL-46 poddanych laboratoryjnemu termoutlenianiu. Wyniki pomiarów pozwoliły wytypować zarówno parametry impedancyjne, jak i wykonanie czujnika w aspekcie najlepszej detekcji zmian stanu oleju.
13
Content available remote The monitoring of the bearing joints with excessive axial clearances using the FAM-C AND FDM-A methods
Gębura A., Tokarski T.
Prace Naukowe Instytutu Technicznego Wojsk Lotniczych
|
2010
|
nr 27
121-136
EN
The intended aim of the paper is to discuss issues resulting from the observation of thee bearing support elements/components in single-shaft turbine engines with excessive axial clearances. Described are parameters and symptoms of such a condition, probable hazards, as well as capabilities of determining it with the FDM-A1 and FAM-C2 methods. Presented are hypotheses formulated by the Authors on subsequent stages of the wearout of bearing support elements/components in an aircraft turbojet engine, which lead to that excessive axial clearances start to arise. Theory of the issue has been completed with results of diagnostic examination of engines and data from the mechanical inspection of the engines after their disassembly.
14
Helical resonator for measurements of dielectrics
Żukociński M., Abramowicz A.
Elektronika : konstrukcje, technologie, zastosowania
|
2009
|
Vol. 50, nr 8
94-97
EN
This paper presents a helical resonator for measurement of complex permittivity of dielectric materials in form of thin sheets at 25 MHz. The indirect method of permittivity reconstruction is investigated. The full-wave 3D electromagnetic simulator is used to analyse the structure, create experiment model and to build lookup database. The results of the experiments are used to verify the possibility of accurate resonant measurement method at such low frequency.
PL
Opisano metodę pomiarową i realizację praktyczną układu pomiarowego w postaci rezonatora helikalnego działającego na częstotliwości 25 MHz. Opisano także sposoby określania przenikalnosci elektrycznej z analizy numerycznej struktury i pomiarów referencyjnych. Trzywymiarowy symulator elektromagnetyczny został użyty do analizy struktury i stworzenia bazy danych w postaci tabel wyników. Resultaty doświadczalne wskazują na możliwość budowy dokładnego rezonatora pomiarowego na niskich częstotliwościach.
15
Content available remote Helical Resonator for Measurements of Parameters of Dielectrics at 25 MHz
Żukociński M., Abramowicz A.
Electronics and Telecommunications Quarterly
|
2009
|
Vol. 55, No 3
515-524
EN
This paper presents a helical resonator for measurement of complex permittivity of dielectric materials in form of thin sheets at 25 MHz. The indirect method of permittivity reconstruction is investigated. The full-wave 3D electromagnetic simulator is used to analyse the structure, create experiment model and build lookup database. The results of experiments are used to verify the possibility of accurate resonant measurement method at such low frequency.
16
Wpływ niedoskonałości elementów na działanie filtru pasmowoprzepustowego z zerem transmitancji na drugiej harmonicznej sygnału
Rudziński A.
Elektronika : konstrukcje, technologie, zastosowania
|
2008
|
Vol. 49, nr 10
100-104
PL
W niniejszym artykule przedstawiono analizę wpływu skończonej dobroci elementów oraz rozrzutów ich wartości na działanie filtru pasmowoprzepustowego z zerem transmitancji. Wyprowadzone zostały przybliżone wyrażenia pozwalające określić wymaganą, dobroć i ograniczenia na rozrzuty wartości elementów składowych filtru.
EN
The aim of this paper is to present an analyzis of influence of finite quality factor and random dispersion of components' values on operation of a bandpass filter with transmission zero. Approximate expressions allowing to determine necessary quality factor and limitations of the dispersion of values have been obtained.
17
Content available remote Koncepcja wyznaczania wskaźnika jakości eksploatacyjnej wybranych obiektów pracujących cyklicznie.
Heinrich M., Jasica G.
Zagadnienia Eksploatacji Maszyn
|
2005
|
Vol. 40, nr 3
111-118
PL
W opracowaniu omówiono zagadnienie oceny jakości eksploatacyjnej na przykładzie urządzeń produkowanych masowo, pracujących w cyklach okresowo-ciągłych. Zapewnienie wysokiej jakości w okresie użytkowania ciągłego w przypadku obiektów, takich jak np. pompy wirowe eksploatowane w cukrownictwie, jest niezwykle istotne. Przerwa w pracy spowodowana uszkodzeniem wiąże się tutaj ze stratami ekonomicznymi. Systematycznie prowadzone badania związane z doskonaleniem obiektów niespełniających wymagań powinny pozwolić na utrzymanie wysokiej ich jakości.
EN
In the paper are presented the exploitation problems of technical objects working in period continuous cycles. The problems are discussed on the examples of rotational pumps operating in sugar factories. The conception of quality factor and investigation method let to control the operations of facilities operating in periodical - continuous cycles. The investigation procedure consists of: - the analysis of defects and their reasons, - the analysis of estimation of the process of operation and service, - introduction of modernization changes which increase reliability, - making decision on the continuation or the end of investigations. The maximum level of quality must be result of the investigations and modernisations of objects and their exploitation processes.
18
Modelling of multilayered dispersive and dissipative media
Narayan J.
Acta Geophysica Polonica
|
2000
|
Vol. 48, nr 3
347-358
EN
This paper presents a frequency domain formulation in agreement with Futterman's third absorption-dispersion relationship, for synthesizing normal incident seismograms for a layered elastic and dissipative media. In the past, synthetic seismograms have been computed in time and frequency domains using attenuation and dispersion phenomena separately as well as simultaneously. The time domain modeling suffers from minimum phase formulation and inadequate treatment of dispersion. Amplitude and phase spectra have been computed using the ratio of spectra of upgoing and downgoing waves in the layers and Fast Fourier Transform (FFT) technique bas been adopted for converting the response in time domain. The results have revealed changes in the reflected wave forms in both frequency and time domains in accordance with the theory of absorption and dispersion phenomena. Results with constant quality factor depict an increase in both attenuative and dispersive effects with a decrease in the quality factor. Frequency dependent and independent quality factors were considered and almost similar responses have been obtained. The time lead caused by dispersion is found to be much smaller when the reference frequency is at the center of the desired frequency band. It has also been observed that the time lead or delay caused by dispersion increases with the travel time. Key words: synthetic seismograms, dispersive media, dissipative media, quality factor.
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