摘要:

AbstractIn the čerenkov laser, as the electromagnetic wave grows by gaining energy from the electron beam, it loses kinetic energy and, thus, its drift velocity decreases. As a result, the synchronism between the propagation velocity of the electromagnetic wave and the drift velocity of the electron beam ceases to be kept and efficient growth of the electromagnetic wave is prevented. to overcome this difficulty, this paper proposes a model for the čerenkov laser loaded with a Kerr‐like medium, the permittivity of which increases in proportion to the square of electric field. Also, a numerical investigation is made to determine how the growth characteristics for the electromagnetic wave are improved with the aid of the finite element method.The numerical result shows that, by choosing a proper value for the nonlinear coefficient of the Kerr‐like medium, the propagation velocity of the electromagnetic wave can be delayed in accordance with the decrease in the drift of the electron beam. Thus, the growth characteristics for the electromagnetic wave can be improved greatly. In addition, it is found that the interaction distance to maximize the electromagnetic wave power extracted from the electron beam can be shortened compared with the case where only a linear dielectric is l

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770601

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe Yasuura method (mode matching method) was applied to the problem of electromagnetic wave scattering by an obstacle in a rectangular waveguide to prove the usefulness of this method as a general‐purpose analysis method. In this paper, the scattering problem of an inductive obstacle with edges placed in a rectangular waveguide is analyzed numerically, taking into account the singularity of the solution at the edges. the inductive obstacle is considered to be a perfect conductor with an asymmetrical triangular cross section with an arbitrary apex angle. Each corner of the triangle is treated as a singularity.The algorithm is presented which takes into consideration the singularity of the solution at the edge, and then the accuracy of the analysis is discussed. As a numerical example, the frequency characteristics of reflection and transmission coefficients versus various parameters are shown including the behaviors of higherorder modes. By taking advantage of the fact that the magnitude of the apex angle can be changed arbitrarily, the effect of the slant angle of the triangle on the incident side exerted on the scattering is discussed. Since the structure can be computed for an apex angle starting from 0°, the solution for an apex angle of 0° or the inductive window is compared with the exact solution by Wiener‐Hopf method so that the analysis error is carrie

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA coupled mode equation for two nonparallel dielectric waveguides is rigorously derived from the Lorentz reciprocity theorem. the waveguides are located close to each other. Two local coordinate systems are introduced to present an intrinsic mode function. A global coordinator system also is employed to solve the coupled mode equation. As a numerical example, a coupling system consisting of two dielectric disks with different radii is analyzed. the coupled mode equation for whispering gallery modes propagating along a circumference of the disks is solved numerically in the global coordinate system. Eigenvalues of the whispering gallery modes are complex numbers because of radiation and dielectric losses. As a result, electric field distribution and the coupling coefficient around the coupling system are obtained quantitatively.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractIt is demonstrated that the step shapes in a rectangular waveguide can be treated rigorously by a transmission equation. an efficient method for computing the characteristics of the step shapes is proposed based on the transmission equation. It is recognized that the step shape is the one in which the derivatives of the shape change in the axial direction diverges. Then the transmission equation is simplified. It is shown that the frequency dependence can be eliminated from the transmission equation if there is no thermal loss in the step shape and that the scale dependence can also be eliminated if the cross‐sectional shape is similar.By the foregoing procedure, the computation time and the number of computation of the F matrix which consumes the most time in the transmission equation method can now be reduced substantially. It is found that the computation speed can be accelerated effectively by more than one order of magnitude in comparison to the method in which the F matrix is computed by numerical integration. the results are verified experimentall

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe filter effect of an SiNxfilm used to passivate a light‐emitting diode (LED) was investigated. the transmission spectrum of an SiNxfilm is dependent on the film thickness, while the wavelength of light emitted from an LED depends on temperature. Therefore, the intensity of emitted light depends on the temperature characteristic of the thickness of the SiNxfilm. LEDs with SiNxfilms whose thicknesses were (3/4 + 15%) λ were realized.The simulation indicated that the content of the temperature coefficients of emission intensity due to the filter effect was between −0.049%/°C and +0.072%/°C when the thickness of the SiNxwas varied as described in the foregoing. On the other hand, the experimental results on the variation of the temperature coefficient due to the filter effect was between −0.01 %/°C and +0.03%/°C. In this study, the agreement between the simulated and experimental results were not in quantitative agreement because the temperature coefficients of the LEDs were not uniform in comparison with the component due to the fil

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe readout signal waveform and recorded mark of magneto‐optic write media are investigated using the magnetic field modulation method. Because overwrite is possible in the magnetic field modulation method, it has been applied to a small magneto‐optic disk in a new audio media system. the magneto‐optic mark recorded by this system has a chevron shape, and the width is highly sensitive to changes in such factors as laser power or ambient temperature. For this reason, it is necessary to design the recording medium so that a sufficiently stable readout signal is obtained for these changes.A numerical integral obtained by polygonal approximation of recorded mark is used, and the readout signal waveform is determined by simulation. By this technique, the readout signal amplitude and crosstalk level that influence the medium and the recording density are determined. Based on this result, the write density of the medium is computed and comparison with measurement values indicates that agreement is excellent. Moreover, by adjusting the tracking offset during readout, it is possible to improve the apparent write power margin. Thus, the technique will be very effective in the design of future high‐density recordin

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA Ta2O5film formed by ϵ‐beam evaporation (EB‐Ta2O5) was nonstoichiometric because of oxygen deficiency, resulting in electron trapping. As a result, the dielectric constant was higher than that of bulk material. the trapped fixed‐charge density increased with a decrease of film thickness.When the film was 300 nm, the trapped fixed Charge density was as high as 1016cm−3. However, when the film was thicker than 300 nm, it decreased rapidly. the dielectric constant approached the bulk value as the film thickness increased, and the film resistance was low because of oxygen deficiency. When the film was 300 nm, the resistivity p was 107− 108ω ‐cm (5 × 105V/cm). When the electric field reached about 7 × 105V/cm, only the current density increased in spite of the slight increase of the electrical field.When the film was thicker than 300 nm, the resis tivity increased and the clamp field became unclear with an increase of thickness. an EL (electroluminescent) device was formed using the EB‐Ta2O5film sandwiched with SiO2films as the luminescent film. the luminance of the device was 100 cd/2. the luminescence spectrum had peaks at 380, 430, 475, and 540 nm, indicating that there were energy levels at 3.2, 2.9

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractPalladium has a strong anticorrosion characteristic and has been used as low‐load contact material. This paper investigates the mechanochemical reaction of palladium, which is believed to cause contact failure due to palladium oxide. As a result, it is found that the formation of palladium oxide did not occur when pressure is lower than a certain value and that critical pressure decreases with a decrease of moisture.It also is found that water vapor suppresses the formation of palladium oxide due to the mechanochemical reaction. It is proposed that the oxidation of palladium is suppressed by the lubrication effect of water vapor. In addition, experiments are carried out under the ambient without water vapor and organic gas; and it is found that the proposition was vali

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA method is investigated for an analysis of the level characteristics of the two‐port active impedance in a CMOS quartz crystal oscillator circuit used widely as a clock source of electronic devices. As a result, it was found that the negative resistance and the equivalent capacitance for arbitrary circuit parameters can be analyzed in relation to the characteristics of the CMOS‐IC itself over a small signal to a large steady‐state signal.The analysis is useful for discussions of initiation of the oscillation in addition to the investigations as to up to what frequency the oscillation takes place definitely with a sufficient small signal negative resistance and to what the resonator current is under the steady‐state osci

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA three‐channel integrated wideband video IC with the possibility of application in high resolution display of 1M pixel was developed.This paper reports first the construction of a wideband voltage amplifier circuit in which a wide output signal dynamic range is obtained. With respect to the construction of this circuit, by compensating for the nonlinearity of the bipolar transistor and the logarithmic compression of the signal voltage, an attempt is made to expand the dynamic range. Moreover, by using an opposite‐phase current to cancel the negative resistance component appearing in the input impedance when compensating for the nonlinearity, it was attempted to flatten the frequency characteristic.With the present circuit construction, by overcoming the process limitation of low‐voltage tolerance, it was possible to ensure wideband characteristics in excess of 140 MHz. In addition, the wideband suppression method of signal crosstalk appearing between channels as side effects of tracking characteristic improvement due to three‐channel integration is reported.By suppressing the influence of common impedance and the differential transmission of each signal, it was possible to suppress lower than ‐43.6 dB the crosstalk between channels below 100 MHz. By the development of this IC, the miniaturization and lowering of cost of high‐resolution display and the improvement of adjustment accuracy and stability characteristics could

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY