摘要:

AbstractTo provide an example of circularly polarized absolute‐value rays in a nondispersive absorbing medium, the theory of ray tracing is presented in the case in which a plane wave is incident on a planar layered medium. Specific tracing methods are presented for the loci of the real phase plane normal, the loci of the projection ray related to the flow line of the normalized Poynting flux, the loci of the circularly polarized absolute‐value rays, and the intensities of these rays. The relationships to Poynting flux and their tracing method are described. Further, in the planar layered medium, an anisotropic projection ray index of refraction is introduced to the projection ray. It is shown that Fermat's principle holds under this index of refraction. On the other hand, Fermat's principle also holds in the tracing of the trajectory of the real‐phase plane normal. In Fermat's principle of the projection ray, its relationship to the energy flux density i

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790601

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

年代:1996

数据来源: WILEY

摘要:

AbstractIn a slot‐line‐type signal‐to‐noise enhancer for a magnetostatic wave, it is shown theoretically and confirmed experimentally that enhancement can be improved by the symmetric slot‐line structure with yttrium iron garnet (YIG) films on both sides of the slot line and by the layered structure of high permittivity materials. It is shown that the improvement in the amount of enhancement requires an increased attenuation constant of the slot line caused by the conversion loss of the linear operation to the magnetostatic wave. The magnetostatic wave radiation impedance is then derived by recognizing the contribution of the magnetic flux density normal to the slot plane among the electromagnetic field components traveling along the slot line to the conversion of the magnetostatic wave. By means of this radiation impedance, the attenuation constant is derived for the symmetric slot line and the slot line with a high permittivity layered structure so that improvement to enhancement is

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790602

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe effects that the arrangement of light rays inside the photorefractive crystals have on the reflectivity of CAT mirrors are analyzed anew. Experiments are performed using BaTiO3crystal and the measured results are compared with those of numerical calculations.First, for generation of beam fanning in photo‐refractive crystals, three different cases of generation are considered, i.e., at the plane of incidence of the crystal, in the range of maximum coupling coefficient, and in the range of maximum coupling strength. Next, the light‐ray incident conditions (incident position, incident angle, and beam radius) and the generating position of beam‐fanning associated with variations of light‐ray arrangement inside the photorefractive crystal are simulated. In each of these three cases, the phase‐conjugate reflectivity is estimated via numerical calculations from which the effects that light‐ray arrangement have on reflectivity is clarified.Finally, experiments are carried out using a BaTiO3crystal and the measured data are compared with the simulated results. It is shown that if the angle of the incident beam with respect to the crystal is large, beam‐fanning is generated at the position where the coupling coefficient is at its maximum. When the angle of incidence is small and in the range of small values of the position of incidence, beam‐fanning occurs in the plane of incidence of the crystal. Using this analysis, the light‐ray arrangement required in achieving high phase‐conjugate reflec

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790603

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe general design principle of the dielectric multilayer bandpass filters proposed by the authors is applied to the case where only the fundamental thickness of dielectric layers are used. The actual design procedure, layer structure, necessary formulation in the design, conditions, and design examples are presented. Further, with respect to various combinations of the parameters, 900 filters are designed and their characteristics are verified to show the distribution of their design errors.In actual designs, the objectives are third‐, fifth‐, and seventh‐order Butterworth and Chebyshev filters (0.5‐dB and 1‐dB ripples) using SiO2and TiO2and the center wavelength of 1.3 μm. The percentage bandwidths are taken to be up to 10 percent with angles of incidence up to 30 deg with P or S polarizations.It is understood that, when the bandwidth is set to be less than 5 percent or when it is set in the range of 5 to 10 percent, it is possible to achieve designed filters with percentage bandwidth errors below 1 percent and 3 percent, respectively. In all Butterworth filters, the insertion loss at the center wavelength was below 0.04 dB. For the objective ripple in Chebyshev filters set at 0.5 dB, the maximum ripples of all filters distribute within 0.15 to 2 dB while, in the case of 1‐dB objective ripple, they are in the range from 0

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790604

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe electromechanical coupling coefficientkcan be determined by measuring the frequency characteristics of admittance. However, it is known that the specimen shape affects the measurement of the admittance frequency characteristics. In this paper, the finite element method was employed to investigate the effects of sample electrode inclination on the electromechanical coupling coefficients. The results indicate that the electromechanical coupling coefficients for the stretching vibration mode (31) of a rectangle, the stretching vibration mode (33) of a bar, and the expansion vibration mode (p) of a disk decrease when the sample electrodes are inclined. No spurious vibration was observed in the transverse vibration of (31) and (p) modes when the sample electrodes were inclined. However, a spurious vibration was observed in the longitudinal vibration of the (33) mode. These observations were confirmed by experiment.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790605

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe equivalent transmission line model originally proposed by Nukiyama [5] and applied to the thickness mode piezoelectric transducers by Kikuchi et al. [6]is reviewed and its characteristics are described. The model is compared with those proposed by Mason [4] and by Krimholz et al. [2]. The equivalent transmission line model developed by Kikuchi et al. [6] was derived from the fundamental piezoelectric equation and Newton's equation of motion via the Laplace transformation. A new equivalent circuit in a time domain was derived as well. By comparing the equivalent circuit in a time domain with the equivalent transmission line model [6], it was demonstrated that the equivalent transmission line model is a fundamental equivalent circuit that is effective both for analyses in a time domain and for conventional analyses in a frequency domain. It is also demonstrated that, when the simultaneity between electric and acoustic signals is neglected, the equivalent circuits [2, 4] can be derived from the equivalent transmission line model.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790606

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

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper discusses the operating principle and performance characteristics of an ultrasonic motor based on the coupled longitudinal‐bending vibrations of a diagonally symmetric piezoelectric ceramic plate. It is well known that longitudinal and bending vibrations couple with each other in a diagonally symmetric piezoelectric ceramic plate.The objective of this investigation is to design a simple and thin ultrasonic motor based on these coupled mode vibrations. The design of a stator for an ultrasonic motor was optimized with respect to vibration mode, capacitance ratio, and direction of vibratory displacement by employing the finite element method. A simple ultrasonic motor was built and its performance was tested. The results indicate that its load characteristics vary widely depending on the contact point of the rotor and the geometry of a piezoelectric plate. Furthermore, attempts were made to equalize load characteristics for bidirectional operations. The efforts revealed that it is possible to equalize the rotation rate, but it is difficult to equalize efficiencies for bidirectional operations. By incorporating a self‐oscillation circuit with an inverter, it is possible to run the motor bidirectionally in a single‐phase

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790607

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

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper describes a new technique for imaging the distribution of nonlinear dielectric constants of ferroelectric materials. This technique is based on the principle that the nonlinear (third‐order) dielectric constants (third‐rank tensor) are very sensitive to the state of the spontaneous polarization and the quality of the crystallization of materials, while the linear (second‐order) dielectric constants (second‐rank tensor) are insensitive to them. Applying this principle, a new microscope for measuring the distribution of nonlinear dielectric properties is developed. This new microscope is used to observe the distribution of the polarization of ferroelectric materials such as lead zirconate titanate (PZT) ceramic and piezoelectric

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790608

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

年代:1996

数据来源: WILEY

摘要:

AbstractIn the hybrid integrated circuit systems which process the RF signal for communications, the transmission loss tends to increase as the frequency is increased, which is a significant problem in the circuit design. The authors have considered thick‐film conductors as conductor materials for the circuit because the thick film is of relatively low cost and can be mass produced. The transmission loss of the RF signal in such a circuit was evaluated experimentally up to 20 GHz.It was found that high‐purity alumina (99.5 percent) is suitable as ceramic substrate material, the transmission loss is too large to be practical in the Ag/Pd conductor system and the transmission losses are not very different and are in the practical range for Au, Ag, Ag/Pt, and Cu conductors. Contrary to the general belief, it was found that the transmission loss can be reduced if the surface of the ceramic substrate is made rough. In order to find the reason, the fine structures of the cross section of the thick‐film conductor was investi

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790609

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

年代:1996

数据来源: WILEY

摘要:

AbstractA normal, open electrical contact pair, mounted in a small relay, was used to make and break repeatedly a dc, 30V/3 Ω resistive circuit up to 100 thousand times; and the relationship between data for each switching and switching interval are analyzed in this paper. Four kinds of switching intervals are set by changing the frequency of applying the rated voltage to drive the electromagnetic coil.No special relationship was found between four different switching operation intervals and data for bounce number at make, arc duration at make/break, and contact resistance at 500 ms after the 10‐A current began to flow.On the other hand, the following points became clear through the experiments.— Temperature at the backside of contacts at 500 ms after the 10‐A current began to flow changes drastically by the difference of the switching interval.— Temperature rise changed linearly and was proportional to the contact resistance at each switching interval.— The more frequent the switching interval, the larger the proportional coefficient.By these results of experiments, the following facts were concluded.— Temperature of electric contact increases with Joule heating of contact resistance and the resistance of the conductor including supporting arms.— The shorter the period of the separated contacts, the larger the temperature difference between measuring point and room temp

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790610

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

年代:1996

数据来源: WILEY