Q factor

As much of the work of service employees is supported by IT, the quality of the service often depends on how the technology is used. Most employees only use a fraction of the functionality available on their desk-top. This may also depend on their personality. We performed research on the relationship of personality and technology acceptance.

This article reports on the research to empirically determine which operations management problems are the most important to small service organizations. The authors asked managers of service organizations to rank a set of operations problems according to their relative importance using Q methodology. In this article, Q method is explained, signiÿcant factors are analyzed, and explanations are o ered for the ranking of the operations problems. The results indicate that forecasting, quality management, and resource utilization are important operational issues for service organizations. However, the results also indicate that facility location and layout, waiting line systems, and distribution requirements planning were for the most part unimportant to the respondent service organizations. In addition, Schmenner's service typology does not provide an explanatory basis for the variations in the factor results. Lastly, the results are used to suggest operations management techniques that should be taught to students who are expected to work in service organizations upon graduation.

The paper reviews several expressions for high-frequency winding resistance of inductors proposed by several authors and compares the theoretical predictions calculated from these expressions with experimental results. It identifies the expressions that yield the most accurate prediction of the winding high-frequency resistance. The comparison shows that the method proposed by Dowell accurately predicts the ac resistance if the winding contains less than three layers. The methods proposed by several other authors accurately predict the high-frequency resistance only in certain frequency ranges. In addition, these expressions yield inaccurate results for the inductor quality factor. One expression, however, accurately predicts both the high-frequency winding resistance and the quality factor of inductors over a wide frequency range from the dc to the first resonant frequency. The paper concludes with a simple and accurate circuit model describing the frequency behavior of inductors.

This paper presents the design, fabrication, and characterization of a microwave resonator as a tool for concentration measurements of liquid compounds. The sensing device is a rectangular waveguide cavity tuned at 1.91 GHz, which exploits the fundamental TE 101 mode in a transmission-type configuration. The coupling structure is optimized by means of a finite element code so as to achieve a high Q-factor. According to the type of substance inside the mixture, its concentration is conveniently related to changes of the S 21 scattering parameter (transmission coefficient) in terms of: 1) resonance frequency; 2) 3-dB bandwidth; and 3) amplitude at the resonance frequency. Experimental tests on liquid solutions in controlled conditions are presented to evaluate the performance of the device.

Dielectric microspheres, with sizes on the order of several wavelengths, support high-quality whispering gallery (WG) modes and provide nonresonant focusing of light into tiny spots termed nanoscale photonic jets. In this chapter, we review properties of more complicated multiple-cavity systems that are formed by microspheres assembled in chip-scale structures. The resonant optical properties of such systems can be engineered on the basis of tight-binding WG modes in photonic atoms. In practical systems of coupled cavities, the optical transport properties are strongly influenced by disorder effects, leading to scattering, localization, and percolation of light. The desirable tight-binding properties require selecting more uniform spheres, which can be achieved by novel methods based on using sizeselective radiative pressure. Due to controllable dispersions for photons, collective emission and absorption, and enhanced light-matter coupling, such structures can be used for developing coupled arrays of microlasers, ultracompact high-resolution spectrometers, and sensors. The nonresonant properties of such systems are connected through subwavelength focusing of light in chains and arrays of microspheres that can be used in a variety of biomedical applications including ultraprecise laser tissue surgery.

We provide the first experimental observation of structure tuning of the electromagnetically induced transparencylike spectrum in integrated on-chip optical resonator systems. The system consists of coupled silicon ring resonators with 10 m diameter on silicon, where the coherent interference between the two coupled resonators is tuned. We measured a transparency-resonance mode with a quality factor of 11 800.

This paper presents a fully integrated 60 GHz two stage power amplifier for wireless applications using common source topology and power combining. The PA is implemented in a 90 nm low power CMOS technology. The output power of the amplifier has been improved with the help of Wilkinson power combining technique. Also the Wilkinson power combiner has been utilized as a part of input and output matching networks to match the 16 Ω at the terminals of the power amplifier to 50 Ω at the output of the Wilkinson network. At 60 GHz the power amplifier achieves 11 dBm saturation output power, 9 dBm output power at 1dB gain compression point and more than 8 dB small signal gain with a peak power added efficiency of 6%. The broadband performance of the gain has been achieved utilizing the cascaded structures. The matching networks are based on high quality factor shielded coplanar transmission lines and fixed 300 fF MIM-capacitors. The detailed design procedure and the achieved measurement results are presented in this work.

As much of the work of service employees is supported by IT, the quality of the service often depends on how the technology is used. Most employees only use a fraction of the functionality available on their desk-top. This may also depend on their personality. We performed research on the relationship of personality and technology acceptance.

This paper presents a multi-band CMOS VCO using a double-tuned, current-driven transformer load. The dual frequency range oscillator is based on enabling/disabling the driving current in the secondary port of the transformer. This approach eliminates the effect of switches connected directly to the VCO tank whose capacitance and on-resistance affect both the tuning range and the phase noise of a

A novel method for designing multiband bandpass filters has been proposed in this paper. Coupling structures with both Chebyshev and quasi-elliptic frequency responses are presented to achieve dual-and triple-band characteristics without a significant increase in circuit size. The design concept is to add some extra coupled resonator sections in a single-circuit filter to increase the degrees of freedom in extracting coupling coefficients of a multiband filter and, therefore, the filter is capable of realizing the specifications of coupling coefficients at all passbands. To verify the presented concept, four experimental examples of filters with a dual-band Chebyshev, triple-band Chebyshev, dual-band quasi-elliptic, and triple-band quasi-elliptic response have been designed and fabricated with microstrip technology. The measured results are in good agreement with the full-wave simulation results.

This study presents new techniques for implementing continuous-time second-order band-pass filters with high-quality factors and asymmetric slopes. The techniques are centred around the realisation of two non-conventional transfer functions which include the non-integer-order Laplacian operator s a ; 0 , a , 1. Four main possible circuit realisations; one based on a frequencydependent negative resistor (FDNR), another based on an inductor and two based on multiple amplifier biquads (MABs) are given and verified using Spice and experimentally for both transfer functions. In addition, a field programmable analogue array (FPAA) realisation is tested and verified. Last but not least, a possible realisation using current conveyors is also given, tested and verified.

This article presents a dual-mode (voltage-mode and current-mode) universal biquadratic filter performing completely standard functions: low-pass, high-pass, band-pass, band-reject and all-pass functions, based on plus type dualoutput current controlled current conveyor transconductance amplifier (CCCCTA). The features of the circuit are that: the quality factor and natural frequency can be tuned electronically via the input bias currents: the circuit description is very simple, consisting of merely single CCCCTA and 2 capacitors: the circuit can provide either the voltage-mode or current-mode filter without changing circuit topology. Additionally, each function response can be selected by suitably selecting input signals with digital method. Without any external resistors, the proposed circuit is very suitable to further develop into an integrated circuit. The PSPICE simulation results are depicted. The given results agree well with the theoretical anticipation. The maximum power consumption is approximately 1.81mW at ±1.5V supply voltages.

This paper presents a quadrature voltage-controlled oscillator (QVCO) based on the coupling of two LC-tank VCOs. A simplified theoretical analysis for the oscillation frequency and phase noise displayed by the QVCO in the 1 3 region is developed, and good agreement is found between theory and simulation results. A prototype for the QVCO was implemented in a 0.35m CMOS process with three standard metal layers. The QVCO could be tuned between 1.64 and 1.97 GHz, and showed a phase noise of 140 dBc/Hz or less across the tuning range at a 3-MHz offset frequency from the carrier, for a current consumption of 25 mA from a 2-V power supply. The equivalent phase error between I and Q signals was at most 0.25 .

Thermal noise is generated naturally by thermal agitation of electrons in a conductor commonly found in opto-electronic devices. The fact that the optical medium is totally immune to noise does not exclude its occurrence in receiver parts. In communication, thermal noise has a major influence to the quality of the receiver. The lower the thermal noise the higher and more expensive is receiver sensitivity. This paper starts with a tutorial on thermal noise in common communication technologies. The major contribution factor to thermal noise power is also discussed analytically. For more comprehensive view, the includes a study on thermal noise effects network performance in terms of BER, maximum Q-factor, eye height and maximum distance. The fiber-to-the-home network is used as a test field to study the impact of two different values of thermal noise on network parameters. At the end of this paper, thermal noise minimizing techniques are also listed.

Methods to determine resonant cavity Q-factor from vector network analyser reflection data are often quite complex. This study presents a simple method which makes use of two least squares algorithms applied sequentially. Firstly, a circle is fitted to the data, which is then projected onto a linear frequency scale using the Ginzton technique. A straight line is fitted to the projected data, and the loaded Q-factor and the resonant frequency are obtained from the line coefficients. The method has been tested on both synthetic and experimental data, and compared with the Kajfez QZERO software, and the results are shown to be accurate to a fraction of 1%.

A novel design for a thin frequency selective surface (FSS) type of metamaterial superstrate for dual-band directivity enhancement is presented as an alternative to a conventional FSS superstrate which is thicker. In the proposed new design, two strip-dipole arrays with the same periodicity, but with different alignments are placed above and below a thin dielectric layer to overcome the problem of different directivities realised at the two bands, when two FSS arrays with dissimilar periodicities are used. On the basis of unit-cell simulation, several important parameters that characterise the thin FSS superstrate are investigated, and the procedure for designing such a superstrate is described. Resonant frequencies and quality factors of the unit cell are compared with those of three FSS antenna composites with different quality factors and the optimal quality factors for the dual-band directivity enhancement are identified. Additionally, how to choose the optimal FSS array size for which the superstrate enhances directivity most efficiently is discussed. An antenna composite has been fabricated to validate the proposed approach, and the measured results show good agreement with the simulated ones.

Chromatic dispersion is very serious issue for communication engineers while designing a wave division multiplexing for optical communication. In the present scenario there is a increasing demand of high speed internet which require more capacity and more bandwidth. The effect of chromatic dispersion can be reduced by compensation technique. [1, 2] The chromatic dispersion also has inverse relationship with FWM. In this paper we used post dispersion compensation along with the fiber Bragg grating to reduce the effect of chromatic dispersion. Also we can compare the Bit error rate at different power levels 5 db, 10 db and 20 db while the length of fiber is fixed. After simulation it is proven that bit error rate is a function of input power level. The pulse broadening is a function of length of fiber which has been shown in this work When the BER increases quality factor decreases and overall fiber optic system degraded. In this paper we also prove that the BER is also a function of Length of Fiber. As the fiber length increases BER also increases. The whole simulationn is performed by Optisystem simulation software. Also by examine the eye diagram it is clear that link performance is improved by using dispersion compensation.

A dual spiral sandwiched thin film inductor with a dimension of 5 mm 5 mm was fabricated by a LIGA-like micromachined process. FeBN magnetic films were used as a core material. The inductance and quality factor value of the inductor were measured approximately 1 H and 4 up to 5 MHz, respectively. Using the FeBN film inductor, a hybrid dc/dc converter (15 mm 12 mm 1.5 mm) was designed and fabricated. The circuit topology of the converter was a zero voltage switching clamp voltage (ZVS-CV) buck converter. An input of 3.6 V was bucked to 2.7 V at a switching frequency of 1.8 MHz. The maximum power was 1.5 W. The measured efficiency of the buck converter reached a maximum value of 80% and kept stable up to 300 mA of load currents at 1.8 MHz.

The authors present the theoretical analysis and experimental demonstration of a novel single-bandpass tunable microwave filter. The filter is based on a broadband optical source and a fiber Mach-Zehnder interferometer and shows a high Q factor over a tuning range of 5-17 GHz. A generalized analysis considering that the optical signal propagates along optical delay lines with a dispersion slope different from zero is presented.

This letter proposes an annular cylindrical dielectric resonator antenna (DRA) with two-port diversity realizing simultaneously omnidirectional horizontally and vertically polarized radiation patterns with low cross coupling. The horizontally and vertically polarized radiation patterns are achieved by exciting the orthogonal TE and TM modes in a single cylindrical dielectric resonator (DR). Due to the high -factor of the TE mode, an air gap and multiple feeding lines are introduced to increase the impedance bandwidth. The proposed antenna provides an impedance bandwidth of 19.1% in the vertically polarized mode and an overlapping bandwidth of 7.4% in the horizontally polarized mode, with the overlapping band ranging from 3.78 to 4.07 GHz. Antenna diversity and multiple-input-multiple-output (MIMO) performance are examined in terms of envelope correlation coefficient and mean effective gain.

The spectral characteristic of a Fano resonance is a distinct and unique asymmetric line shape. It arises from the destructive interference between a bright continuum mode and a discrete dark mode. Metamaterials and plasmonics have facilitated the observation of Fano resonances in the realm of classical electrodynamics and have spurred intense interest to study and to exploit their peculiarities due their low loss and very sharp resonant features. Here, we survey the excitation of Fano resonance at terahertz frequencies by using asymmetric metamaterial structures. In particular, we discuss the high of Fano resonances, their sensitivity to the asymmetry parameter and potential applications. We believe that the manipulation of terahertz radiation by exploiting Fano resonances in terahertz metamaterials could usher in next-generation terahertz photonic devices for delay, storage, filtering, sensing, and nonlinear applications. . His current research interests include terahertz metamaterials, plasmonics, tunable low loss superconductors and transition metal oxide based metamaterials, and high Fano resonances in terahertz metamaterials. He also likes to design ultra-high RF cavities for accelerator applications.

Evolutionary structural optimization (ESO) method is based on a simple idea that the optimal structure can be produced by gradually removing the ineffectively used material from the design domain. ESO seems to have some attractive features in engineering aspects: simple and fast. In this paper, ESO is applied to optimize shaft shape for the rotating machinery by introducing variable size of finite elements in optimization procedure. The goal of this optimization is to reduce total shaft weight and resonance magnification factor (Q factor), and to yield the critical speeds as far from the operating speed as possible. The constraints include restrictions on critical speed, unbalance response and bending stresses. Sensitivity analysis of the system parameters is also investigated. The results show that new ESO method can be efficiently used to optimize the shape of rotor shaft system with frequency and dynamic constraints.

Transformer-based series power combiners are analyzed within the context of reconfigurable, watt-level, wideband digital envelope tracking transmitters. A model is developed for designing and analyzing transformer-based switchable series combiners. This model takes into account losses in the windings and nonideal mutual coupling, as well as the effect of switching and scaling the input amplifiers on the combiner efficiency, input impedance, and power combining ratio. Optimum combining efficiency is derived for a combiner with scaled sources. Based on the developed model, a four-element 29.5-dBm power amplifier with 31% peak efficiency at 1.9 GHz, using a 1.5-V supply is designed and simulated in IBM 130-nm CMOS technology. The efficiency drops to 14% at 12 dB power back-off when elements are turned off. The amplifier maintains an output power 25 dBm from 1.8 GHz to 2.5 GHz. The studies presented in this paper can be extended to any series combiner implementation and any frequency range, which can be effective in the design of watt-level power amplifiers in submicrometer CMOS technologies.

In this paper we suggest using a nine element model to represent metal-insulator-metal (MIM) capacitors up to 20GHz. The model suggested is a nine element pi circuit that includes interconnect resistance and inductance as well as substrate parasitics. This paper also identifies the procedures to extract the nine element lumped MIM capacitor model and to optimize the model to fit the measured data up to the self resonant frequency. A good fit between the modeled and measured effective capacitance and Q factor have been obtained in this work.

· This article is based on research into patients' perceptions of being in hospital. · Time, ordinarily taken for granted, becomes a signi®cant problem for people in hospital. · Patients seek control over time that they do not seem to have during their stay in hospital.

Several low-profile 250-m-high -band cavity resonators are demonstrated with resonant frequencies near 26 GHz and unloaded quality ( ) factors greater than 400. The air-filled copper cavity resonators are fabricated on a silicon substrate using a photolithographic process. A microrectangular coaxial transmission-line feed is integrated in the same process. Four resonators with different mechanical support structures are demonstrated. The resonators are designed using the finite-element method and simulation of both the resonant frequency and factor agree well with measurements. Index Terms-Cavity resonator, coaxial transmission line, photolithography, quality ( ) factor.

In this paper, impact of conventional silicon technology parameters on characteristics of passives is studied. For both inductors and capacitors, cost-effective modules, which integrate easily into wiring BEOL (Back-End Of Line) in a conventional silicon technology and provide high Q factor components are presented. For an inductor of 3 nH, designed for 2 GHz frequency applications, and fabricated in thick Cu as an add-on module, Q factor of ~24 is reached. The Metal Insulator Metal (MIM) capacitor module with outstanding RF performances and the Q factor ranging 100-1000 in the few GHz frequency range is developed in the Al BEOL. Compact lumped element SPICE models for both components are proposed and verified.

In this letter the performance of a free space optical (FSO) communication link in the presence of fog is experimentally investigated in an indoor environment. A dedicated indoor atmospheric chamber, replicating the outdoor environment, is being used to evaluate the FSO link performance under the fog condition. Theoretical analysis supported by the experimental evaluation has been carried out for the intensity modulation/direct detection on-off keying non-returnto-zero (OOK-NRZ), OOK return-to-zero (OOK-RZ) and four pulse position modulation (4-PPM) modulation formats at the Ethernet baseline data-rate. The results shown indicate that the 4-PPM signalling scheme is the most robust to the fog attenuation due to its high peak-to-average power ratio. Moreover, results also show the potential of the indoor atmospheric chamber to replicate outdoor atmospheric effects (such as fog) and be able to quickly characterise and assess the FSO system under a controlled environment.

Sea bed logging (SBL) is a new technique for detection of deep target hydrocarbon reservoir. Powerful electromagnetic (EM) transmitter is required for the transmission of EM signal underneath the seabed. New aluminum transmitter with yttrium iron garnet (Y 3 Fe 5 O 12 ) based magnetic feeders was used in a scale tank to increase the magnitude of the magnetic field. Yttrium iron garnet samples were prepared using self combustion technique at different sintering temperatures of 750°C, 950°C and 1150°C. Characterizations of Y 3 Fe 5 O 12 samples were done by using XRD, RAMAN, FESEM and Impedence network analyser. X-ray diffraction results revealed that yttrium iron garnet phase with good crystallinity appeared at sintering temperature of 1150°C. Nanoparticles size ranging from 60 to 110 nm was investigated. Raman results also confirmed garnet structure of yttrium iron garnet at sintering temperature of 1150°C. Field emission scanning electron microscopy (FESEM) was used to image the morphology of the Y 3 Fe 5 O 12 nanoparticles. Magnetic properties of Y 3 Fe 5 O 12 magnetic feeders illustrates that Y 3 Fe 5 O 12 has high Initial permeability (58.054), high Q-factor (59.842) and low loss factor (0.0003) at sintering temperature of 1150°C. Y 3 Fe 5 O 12 magnetic feeders with high Q factor were chosen for new aluminum EM transmitter. Experiments with a scale factor of 2000 were carried out in scaled tank. It was found that Al transmitter with Y 3 Fe 5 O 12 magnetic feeders increased magnitude of magnetic field strength up to 180%.

The highest Q factors for polycrystalline diamond resonators (also the highest Q factors for a cantilever beam made of any polycrystalline material) have been measured, whose undoped poly-C films grown at 780 degC. For boron doped poly-C films or poly-C films grown at a growth temperature of 600 degC, significantly lower Qs were observed. The doped poly-C film exhibited a peak in dissipation at 673 K, suggesting the existence of a dominant defect in these films that maybe related to boron doping. In addition, the temperature dependence of the poly-C resonators was examined, and a temperature coefficient of resonance frequency in the range of -1.59 x 10-5 degC-1 to -2.56 x 10-5 degC-1 was observed.

Resonators are traditionally characterised by their quality factor Q, which is inversely proportional to the relative bandwidth. Small antennas are often resonant, so they can be characterised by a Q, except for the fact that the correct quality measure of an antenna is the inverse Q, that is the relative bandwidth, rather than Q. Still, it has become common to study fundamental size limitations of small antennas in terms of a so-called radiation Q (or antenna Q). This study explains how this intrinsic radiation Q relates to: (i) the bandwidth -efficiency product of small single-resonance-type antennas, (ii) the gradual cut-off of spherical waves for wideband gradual-transition-type small antennas and (iii) the number of resonances needed to cover a certain frequency band for wideband cascaded-resonance-type small antennas. The study also introduces one intrinsic radiation Q for basic single TE and TM spherical mode sources, and another for combined TE and TM sources.

This paper presents a novel high-Q inductor using conventional grounded active inductor and feedback parallel resonance circuit. The proposed high-Q inductor (HI) consists of the conventional active grounded inductor and feedback parallel resonance circuit which is composed of low-Q spiral inductor and capacitor. The novelty of the proposed structure is based on the increase of Q-factor by feeding parallel resonance circuit into gyrator structure. The high-Q inductor is fabricated by 0.18um Hynix CMOS technology. The fabricated inductor shows inductance of above 45 nH and Q-factor of over 250 around 5GHz.

A novel BEMD based Iris recognition system is presented. A multilayer processing for features extraction makes the system efficient. The use of geometrically described details information makes the iris signature very efficient in reducing false positive and false negatives occurrences. Preliminary results of the proposed algorithm seem to indicate BEMD can give high accuracy in iris recognition subsystems in comparison with other techniques.

Objective: E-pharmacies are web sites selling prescription-only medicines and other products including non-prescription and complementary medicines to consumers via the internet. This study aims to evaluate the quality of global e-pharmacies, discuss whether e-pharmacies support the safe and appropriate use of medicines, and consider how we can protect consumers in the future. Methods: A survey of public information published on global e-pharmacy web sites was conducted between July and September 2001. We used a meta-search engine, Copernic, and the search terms of 'online' or 'internet', and 'pharmacy', 'pharmacies' and 'medicines' to identify a sampling frame of global e-pharmacies. We surveyed all web sites in the sampling frame except those under construction or only offering electronic refills, membersonly and non-English web sites. Survey data included country of origin, range of medicines sold, prescription requirements, availability of online medical consultations and pharmacists' advice, quality accreditation seals, policies and advertisements. Results: E-pharmacies operated in at least 13 countries; however, the country of origin could not be identified for 22 web sites. Twenty web sites (19%) appeared to supply prescription-only medicines with no prescription required. Only 12% of e-pharmacies displayed quality accreditation seals. We observed information published on e-pharmacy web sites that potentially undermines the safe and appropriate use of medicines. Conclusion: Safeguarding consumers and ensuring the quality of web sites that sell medicines across state and national boundaries is both complex and difficult. Strategies to improve the quality of e-pharmacies include independent third-party regulation of providers, evaluation and enforcement of sanctions in cases of dissemination of fraudulent or harmful information and practices, self-regulation and consumer education. The development of internet regulatory technologies themselves and the resolution of jurisdictional issues offer future solutions but international co-operation is vital.

This paper reports theoretical analysis and experimental results on a new class of rectangular plate and ringshaped contour-mode piezoelectric aluminum nitride radio-frequency microelectromechanical systems resonators that span a frequency range from 19 to 656 MHz showing high-quality factors in air (Q max = 4300 at 229.9 MHz), low motional resistance (ranging from 50 to 700 Ω), and center frequencies that are lithographically defined. These resonators achieve the lowest value of motional resistance ever reported for contour-mode resonators and combine it with high Q factors, therefore enabling the fabrication of arrays of high-performance microresonators with different frequencies on a single chip. Uncompensated temperature coefficients of frequency of approximately 25 ppm/°C were also recorded for these resonators. Initial discussions on mass loading mechanisms induced by metal electrodes and energy loss phenomenon are provided.

An oscillator with a high-order ( 2) resonator has multiple stable modes of oscillations. The stable modes for one such oscillator, having a fourth-order resonator, are found using a nonlinear analysis. By using a proper nonlinear active topology and tank component values, the fourth-order oscillator can generate either of the two distinct frequencies 1 or 2 . A method is introduced to dynamically switch between the stable modes of oscillations. It is shown that the phase noise of this fourth-order oscillator, when generating only one of its resonant frequencies, is comparable to the phase noise of a second-order oscillator using the same active topology and resonator quality factor. Furthermore, the fourth-order oscillator has better phase noise and/or higher tuning range in VCO implementations compared to the commonly used switched resonator oscillators. The claims have been verified experimentally through an integrated oscillator prototype with 1 = 2 4 GHz and 2 = 4 7 GHz fabricated in a standard 0.18 m CMOS technology. The oscillator draws 1.89 mA current of 1.8 V supply. The 1 MHz offset phase noises of the fourth-order oscillator for 1 = 2 4 GHz and 2 = 4 7 GHz are 122.4 dBc/Hz and 123.4 dBc/Hz, respectively.