摘要:

AbstractThe mutual synchronization characteristics at microwave frequencies have been studied from a practical viewpoint to combine the outputs from several oscillators and obtain a high power. However, in most of the studies, Van der Pol oscillators are used as a model of the oscillator. It is well known that the experimental results of the injection locking characteristics of Van der Pol oscillators cannot be predicted accurately as the injection signal becomes larger. In the previous report, an oscillator model was proposed with which the load characteristics of the microwave oscillator are expressed much more accurately. It was demonstrated that the analysis on the injection locking characteristics based on this model agree well with experimental data. In this paper, a new oscillator model is used and a quantity called the degree of coupling between the oscillator and the transmission line is introduced. In the system in which the oscillators are coupled with frequency‐dependent transmission lines, the effect of the oscillator coupling system on the synchronization characteristics is investigated. The circuit condition for power combining is found. Good agreement with the experimental results is confirme

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711001

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

年代:1988

数据来源: WILEY

摘要:

AbstractRecently, we discovered an LST cut which utilizes leaky surface waves for a high stable quartz crystal for SAW devices. This paper examines experimentally the properties of the LST cut. Due to an error for the cut angle for the LST cut, zero temperature coefficients are sometimes not obtained. However, it was shown that such coefficients can be obtained by varying the direction of wave propagation within the cut plane. We examined SAW resonators and oscillators in a 180‐MHz band. We obtained the temperature characteristics of the LST cut in the temperature range from −20 to 80°C with deviations as small as 15 ppm. The obtained Q was as high as 22,500. One of the features of the leaky surface waves is that they have a large value for the propagation velocity. We took advantage of this feature and manufactured SAW filters for 1.8‐ and 4‐GHz bands. Their characteristics are presented in th

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711002

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe geometrical optics theory of modal waves propagating along optical waveguides is described. The theory is general and thus applicable to the general classes of inhomogeneous waveguides including aniso‐tropic media. This paper points out that the light ray, which is the fundamental concept in geometrical optics, is to be definable as the energy ray and the wave‐normal ray. The variational principles valid for these two definitions are explained. The energy ray is the well‐known ray that shows the path of energy transport. The wave‐normal ray is defined to be the locus of the wave‐normal vectors perpendicular to the wavefronts. The variational principles that describe these two rays are different, and therefore the ray equations for both rays are different in anisotropic media. The former is known as Hamiltonian optics, but the latter is not yet established as geometrical optics. It is pointed out that the latter should be used to describe the geometrical behaviors of guided modes and the propagation of modal waves without any logical contradiction. Optics describing guided modes in terms of the wave‐normal rays is called guided wave optics, and some differences from Hamiltonian optics are discussed using sever

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711003

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

年代:1988

数据来源: WILEY

摘要:

AbstractAlthough a conventional solder bump formation on Al pad uses an evaporation of Pb and Sn on the underlying metal (Au/Cu/Cr, Au/Pt/Ti, etc.) and reflow, it has the disadvantages of high equipment cost and complex process. By applying an ultrasonic soldering technique, in this work, solder bumps were formed directly and selectively on an Al pad without underlying metal. The sample chip used in the experiment had 118 Al pads which were 1.5 μm thick and 100 μm□, and anticorrosive Sn‐37 Pb‐5 Ag was used as a solder. By examining the factors affecting the bump formation percentage, an optimum condition was selected [(1) chip preheating temperature: above 280°C; (2) solder temperature: 280°C; (3) distance between chip and ultrasonic horn: ≈︁0 mm; (4) dip time: more than 8 s; (5) ultrasonic power: more than 135 W]. Using this condition, bumps were formed without damaging the passivation film, which was also the case on 30 μm □ pads with 50 μm pitch without bridging. The bump height was approximately 36 μm on 100 μm □ pads with a variation of ±6 μm. Since the shear force of the bump was on the average 32.5 g and all the breakage occurred within the bumps, a strong adhesion at the interface is guaranteed. The interface contained a compound several 1000 Å thick with a 4 : 1

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711004

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

年代:1988

数据来源: WILEY

摘要:

AbstractIn the fabrications of polycrystalline silicon thin‐film transistors (TFTs), doping of impurities is often carried out by ion implantation. In this study, dopings of phosphorus and boron were carried out by an ion shower doping technique, where the rf plasma of H2‐diluted PH3or H2‐diluted B2H6gas with a magnetic field was used for the ion source. To form the source‐drain regions using this technique, the doping characteristics such as sheet resistivity and impurity profiles in polycrystalline Si were investigated. Using the conditions obtained experimentally,nandpchannel Si gate polycrystalline Si TFTs were fabricated on a fused silica substrate by using a CMOS process. It was also confirmed that the conventional photoresist can be used for this process. For then‐channel transistor, field‐effect mobility μ = 3 cm2/V·s, threshold voltageVth= 5 V, and on‐off current ratioION(VD= 6 V,VG= 10 V)/IOFF(VD= 6 V,VG= 0 V) ≌ 106were obtained forW/L= 12 μm/6 μm. In thep‐channel transistor, the characteristics were similar to those obtained by ion implantation. The ion shower doping technique made it possible to fabricate polycrystalline Si TFTs with a CMOS structure, using a simple apparatus. By using this technique, a large area pro

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711005

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe development of the fiber‐type laser is desired for simple construction of the optical system for several fiber sensor applications. Therefore, in this paper the fabrication of several types of dye‐doped plastic fibers and the laser properties have been studied. When a sheet of dye‐doped fibers was used as an active element and pumped by a pulsed N2laser, the tunable intense radiation was generated over a wide wavelength region. By using two types of dye‐doped fiber sheets, almost the entire visible region could be

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711006

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper considers an object moving on a belt‐conveyor or on a turntable, and describes a system which measures with a high speed its shape and the cross section in horizontal and vertical directions. In the measurement, the object is scanned with a high speed by He‐Ne spotlight through a high‐speed rotating mirror with 10 mirror‐faces. The object is placed on a turntable and rotated 360 deg by a stepping motor. The two‐dimensional information of the scanned point is acquired by PSD. The operation is performed in synchronization to the scanning by a personal computer, and the cylindrical coordinates (r, z, θ) of 4800 points on the object are determined with as high a speed as 980 ms (200 μs per coordinate). A feature of this study is that the speed is improved by combining a high‐speed rotating mirror and a high‐speed PSD. Another feature is that the reference table for coordinate determination is stored so that the speed of the computation can be improved. At present, approximately 3 min is required by BASIC to display the coordinates, but the cross section can be displayed in 0.4 s using the m

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711007

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

年代:1988

数据来源: WILEY

摘要:

AbstractSingle‐mode optical fibers with an α‐power index core (α = 1, 2, 6, ∞) and a triple clad have been designed under the following two conditions: (I) the total dispersion at wavelengths of 1.3 and 1.55 μm is zero; and (II) the cut‐off wavelength λcfor the second mode is less than 1.15 μm. In this paper, the sensitivity of the total dispersion, the equivalent bending radius (the radius at which the bending loss is 0.01 dB/km), and the splice loss of those fibers are discussed. The clad has an ideal triple layer structure (the relative index difference between the first and outer cladding is Δ2and that between the second and outer cladding is Δ3). For a given value of α which determines the core refractive index profile, Δ1. (the relative index difference between the core and outer cladding), anda(core radius) can be chosen freely. In this paper, for a given α the fiber, satisfying conditions (I) and (II), was designed under the conditions that (1) Δ1= const, and (2)\documentclass{article}\pagestyle{empty}\begin{document}$ A\mathop \Delta \limits_ = \int\limits_0^{a/w} {n(r/w,\;\lambda)dr\; = - const(w\mathop \Delta \limits_ = a + t_1 + t_2, t_m;} $\end{document}m‐th cladding layer width,m= 1, 2). Comparing the fiber with a core of α = 1, 2 and 6 (t2/t1= 1.0, Δ2<0, Δ30 and Δ3<0 was investigated and compared with t

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711008

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

年代:1988

数据来源: WILEY

摘要:

AbstractA method of analysis based on the finite‐element method is presented for the problem of plane wave diffraction from metallic gratings with arbitrary complex permittivity. First, the problem of diffraction of a plane wave from the metallic reflected‐type grating is analyzed rigorously as a two‐media boundary value problem by the finite‐element method. Next, a new method is proposed in which an approximate boundary condition using the surface impedance is incorporated into the discretized equations by the finite‐element method. Especially, in the method of using the surface impedance approximation, the region to be analyzed is reduced substantially from the one for the two‐media boundary value problem, and the computational effort is expected to be reduced significantly. The diffraction characteristics of grooved gratings with sinusoidal, triangular and rectangular profiles are actually calculated and the results are compared with those by other methods and experiments. In the case of the TE wave incidence, it is found that the results by the two‐media boundary value problem and those by the surface impedance approximation agree well. On the other hand, in the case of the TM wave incidence, the results are substantially different depending on the grating profile. By comparison of the results with those based on the assumption of a perfect conductor, it is found that the loss in the metal must be considered at a longer wavelength in the case of the TM wave incidence than in the case of the TE w

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711009

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

年代:1988

数据来源: WILEY

摘要:

AbstractA dielectric waveguide isolator with a new open structure is proposed which makes use of the magnetic loss of the ferrite. The analysis is not based on the conventional two‐dimensional approximation but is a rigorous three‐dimensional approach taking into account the waveguide width and is based on the mode matching method. From the numerical results, it is demonstrated that an isolator based on the TM excitation is possible which cannot be found by the two‐dimensional approach. Subsequently, the isolator is operated experimentally and the results are shown to agree well with the theoretical prediction. Further, as a method for development of the characteristics, the experimental results for the structure loaded with a lossy material are pres

ISSN:8756-663X    

DOI:10.1002/ecjb.4420711010

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

年代:1988

数据来源: WILEY