1,721,117 research outputs found
Fourier transform analysis of a ridge waveguide and a rectangular coaxial line
No full textA novel technique based on the Fourier transform is applied to analyze a ridge waveguide and rectangular coaxial line. On the basis of the image theorem the ridge waveguide and rectangular coaxial line are transformed into a guide with an infinite number of grooves. The dispersion relations for the ridge waveguide and rectangular coaxial line are obtained in rigorous, yet simple series forms. Numerical computations show that our series solutions converge fast and agree with others
Dispersion equation for groove nonradiative dielectric waveguide
No full textA rigorous expression of the dispersion equation for a groove nonradiative dielectric (GNRD) waveguide is obtained from the Fourier transform and mode-matching. The image theorem is utilised to transform a GNRD waveguide into an infinite number of GNRD waveguides, thereby representing the dispersion equation in a fast-convergent, numerically efficient series
USING TERM DEPENDENCIES OF A THESAURUS IN THE FUZZY SET MODEL
No full textThe conventional fuzzy set model has been criticized to generate incorrect ranked output in certain cases due to undesirable properties of MIN and MAX operators. We have defined an operator class called positively compensatory operators giving high retrieval effectiveness and have enhanced the fuzzy set model by using a pair of positively compensatory operators instead of MIN and MAX operators. If a thesaurus is used to represent the documents stored, we can apply a particular methodology to document ranking. In this paper we propose a new thesaurus-based document ranking method called KB-FSM by expanding the enhanced fuzzy set model with term dependence information from a thesaurus. KB-FSM avoids all the problems of the previous methods such as Relevance, R-Distance and K-Distance. We also show through performance comparison that the proposed method provides higher retrieval effectiveness than the others proposed in the past
A novel active inductor and its application to inductance-controlled oscillator
No full textThis paper describes a novel active inductor using a common-source cascode FET with an inductive feedback. A compact lossy active inductor, which consists of a common-source FET and a feedback resistor, was used as the feedback inductor to achieve high Q-factor and tunability, as well as reduce the chip size. The fabricated active inductor achieved more than 100 Q-factors with the maximum value of 3400 over the frequency range of 200 MHz, in the vicinity of 1.7 GHz. Inductance was tuned from 9.6 to 56 nH at 1.7 GHz by the variation of the feedback resistance of the lossy active inductor. Using this active inductor (as a frequency-selective element in the resonator), a monolithic inductance-controlled FET oscillator was fabricated, which demonstrated an 18% frequency-tuning range from 1.73 to 2.07 GHz, with an output power range from -9.3 to -6.3 dBm
A circular cylindrical dipole antenna
No full textThe problem of a circular cylindrical dipole antenna is revisited. The Fourier transform and mode matching are used to obtain its rigorous solution in a convergent series. Our solution is compared with other results in terms of antenna admittance and current distribution. The angular radiation patterns of a circular cylinder antenna are shown for different circular cylinder radii of a dipole antenna. (C) 2001 John Wiley & Sons, Inc
THE FUZZY SET MODEL-BASED ON N-ARY POSITIVELY COMPENSATORY OPERATORS
No full textWe have enhanced the fuzzy set model by replacing MIN and MAX operators with binary positively compensatory operators. Though the binary operators provide higher retrieval effectiveness, they can give different document values for logically equivalent queries, e.g. t1 AND (t2 AND t3) and (t1 AND t2) AND t3. This is because they do not satisfy the basic boolean processing laws such as distributive. In this paper we propose n-ary positively compensatory operators by extending the binary forms, which alleviate the aforementioned problem. We show through performance evaluation that the n-ary operators provide better retrieval effectiveness than the binary
Characterization of Eu-doped SnO2 thin films deposited by radio-frequency sputtering for a transparent conductive phosphor layer
No full textEu-doped SnO2 thin films deposited by radio-frequency (rf) magnetron sputtering have been studied for the transparent conductive phosphor layer, which is transparent in visible light, electrically conductive, and luminescent. The resistivity of the SnO2 film increased as the firing temperature and Eu concentration increased. The film showed an excitation peak at 300 nm and an emission peak at 588 nm. The maximum photoluminescence and cathodoluminescence intensity was observed under conditions of 1.0 atom % Eu doping and a 1200 degrees C firing temperature; the resistivity was 0.5 Omega cm and the transmittance was above 70%. The relation between the resistivity and cathodoluminescence intensity has been discussed.Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
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