bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wide dynamic range digital signal processing system for a laser radar
Authors: Abo Makoto , Nagasawa Chikao 
Published: July 2007

AbstractThe strength of laser radar return signals from the atmosphere is inversely proportional to the square of the range so that the long‐range return signals are very weak in comparison with the short‐range signals. Thus, the dynamic range of the return signals is extremely wide. Output signals from the photomultiplier tube (PMT), the main detector in the laser radar receivers, become analog signals when the incident light is strong. However, as the incident light becomes weaker, these signals gradually change to discrete pulses. Usually, to cover their wide dynamic range, multiple signal processing systems designed for different strengths of the incidence light are used. In this paper, a new method of covering the wide dynamic range of signals, from extremely weak light to comparatively strong light, with only one signal processing system is proposed and verified experimentally. The output signals of the photomultiplier are converted to digital signals by an A‐D converter whose sampling time is equivalent to the time constant of the photomultiplier circuit irrespective of the output signal strength. Next, the mean, variance, and pulse count value are calculated from the digital signals. It is confirmed that when this method is used for actual atmospheric observations, laser radar signals with a wide dynamic range can be processed with only one signal processing system.
Electrochromic and electromotive force characteristics of electrochemical polymerization of aniline
Authors: Iida Yosinao 
Published: July 2007

AbstractA polyaniline film was deposited on a mesa glass by the constant rising voltage method using electropolymerization of electrolytic solutions containing five different kinds of compositions. There were three types of relationships between the electropolymerization total charge and voltage rise speed. When the charge decreased rapidly with an increase of voltage rise speed, the deposited film had an electrochromic (EC) characteristic. When the total charge decrease was slow, the deposited film had a different EC characteristic. When the total charge did not change with an increase of voltage rise speed, the deposited film did not have an EC characteristic but potentially it had an electromotive force (emf). The EC and emf were investigated using platinum and mesa glass opposing electrodes. As a result, it was found as reported that the EC characteristic was caused not by dopant bleaching in the supporting electrolytic solution but by the formation of a quinoidimine structure generated by oxidation of a polyaniline film. When a film was composed of a polyaniline structure which was doped easily with ions during oxidation, the film had an emf.
Optical control of the printed dipole antenna
Authors: Nishimura Kazuo , Tsutsumi Makoto 
Published: July 2007

AbstractThis paper describes the various properties of the printed dipole antenna on optically plasma‐induced semiconductor substrates. These properties are analyzed by using the spectral domain moment method. The input impedance and radiation pattern were calculated within the plasma densities from 0 to 2.0 × 1017m−2for semiconductor silicon substrate.Considering the equivalent circuit performance of the antenna, it is shown that the optical illumination is equivalent to loss loading to the antenna. Therefore, it reduces the input impedance and the radiation pattern also has significantly smaller amplitude compared to that without optical illumination. A half‐wavelength antenna is fabricated on a high‐resistivity silicon wafer by aluminum vapor deposition. The input impedance and radiation pattern were measured at the S band. The measured results agree considerably well with the theory.
Simple calculation method of the intermodulation distortion of multiple‐carrier amplifiers operating in weakly nonlinear region
Authors: Suematsu Noriharu , Iida Akio , Takagi Tadashi , Urasaki Shuji 
Published: July 2007

AbstractSimple calculation method of the intermodulation distortion of multiple‐carrier amplifiers operating in weakly nonlinear region is presented. This method is based on the approximation that is effective when (1) the transfer characteristics of carriers are regarded as linear, and (2) the third‐order intermodulation distortion ratio versus the output power has 2 dB/dB slope. As the number of the carriersn→∞, the intermodulation distortion ratio approaches the value of 10 log10(3/2) + 6 = 7.76 dB higher than the third‐order intermodulation distortion ratio in the case of two‐carrier amplification at the same output power.
An approach to realize deep submicron multilevel interconnection using low‐resistance and low‐ϵ materials
Authors: Homma Yoshio , Kusukawa Kikuo , Furusawa Takeshi , Miyazaki Hiroshi , Kobayashi Nobuyoshi 
Published: July 2007

AbstractThis paper discusses techniques for improving the performance of the multilevel interconnection of deep submicron level feature sizes, through the reduction of diffusion layer resistance, contact resistance, metallization resistance, and decrease in permittivity of interlevel dielectrics, and its global planarization. Silicidation of contact hole becomes insufficient for reducing resistance when the contact hole is extremely miniaturized. Contact between metal layers, i.e., the metallized diffusion area and the metal plug, is preferable. In order to reduce signal propagation ideally in interconnection, both low permittivity dielectrics and low resistance metallization are necessary. For reducing metallization resistance, adoption of Cu metallization is suitable.A high‐temperature Cu dry etching and a passivation technique have been developed to reduce contamination by Cu. To provide globally planarized low‐permittivity interlevel dielectrics, an organic spin‐on‐glass (SOG) material with excellent gap filling and relative dielectric constant lower than 3 was developed. Two‐level, globally planarized interconnection test devices were fabricated by applying CMP using silica slurry and a foamed fluorocarbon polishing pad.
Efficiency enhancement in a Čerenkov laser by varying permittivity—taking into consideration mode scattering
Authors: Sata Masahiro , Kamata Hisashi , Shiozawa Toshiyuki 
Published: July 2007

AbstractThis paper considers a model of a Čerenkov laser consisting of a relativistic electron beam and a parallel plate waveguide loaded with a dielectric thin film. By means of numerical analysis, the improvement of the growth characteristics for the electromagnetic wave and the efficiency in energy conversion is discussed. In the Čerenkov laser, the growth of the electromagnetic wave is caused by the transfer of the kinetic energy of the electron beam to the electromagnetic energy. As a result, the drift velocity of the electron beam is decreased gradually so that the synchronism with the phase velocity of the electromagnetic wave cannot be maintained and an efficient transfer of energy is prevented. Thus, the permittivity of the dielectric material composing the waveguide is increased gradually along the direction of the propagation for the electromagnetic wave to reduce the phase velocity of the electromagnetic wave. In this manner, the synchronism with the drift velocity of the electron beam is maintained, leading to an efficient transfer of energy. The variation of the permittivity causes power loss due to the mode scattering of the electromagnetic wave or the reflection or conversion to higher‐order modes.In this paper, the effect of the mode scattering is taken into account for detailed numerical analysis of the amplification characteristics for the electromagnetic wave. It is shown that the efficiency in energy conversion from the electron beam to the electromagnetic wave and the amplification characteristics of the electromagnetic wave can be significantly improved.
Characteristics of polarization splitters constructed from a circular hollow pit outside the cores
Authors: Kameda Kazunori , Hosono Toshio 
Published: July 2007

AbstractIn this paper, a polarization splitter is proposed in which a single‐core fiber (Fiber 1) and a fiber with a circular hollow pit outside the core (Fiber 2) are coupled. Corresponding to the extraction of the two linear polarizations (x and y polarizations) from the HE11 mode excited in to Fiber 1, the polarization splitting method can be clasified into the x‐polarization type or the y polarization type. In the x‐polarization type, the x‐polarization is extracted from Fiber 1 and the y‐polarization from Fiber 2. In the y‐polarization type, the y‐polarization is extracted from Fiber 1 and the x polarization from Fiber 2. This paper discussed the structural parameters (core radius, relative refractive index difference, and core spacing), which reduce the device length of the x polarization and y polarization types and at the same time make the extinction ratio small. The main results are as follows: (1) When the relative refractive index difference of Fiber 2 was made constant, the minimum values of the device length and the extinction ratio of the x polarization type can be made smaller than those of the y polarization type. (2) When the relative refractive index difference of Fiber 2 is increased from 0.4 percent to 1.0 percent, 1 the device lengths of both the x‐ and y‐polarization types can be reduced by 0.26 times, and 2 the minimum value of the extinction ratio of the x polarization type increases +4.1 dB from ‐38.2 dB and that of the y polarization increases +4.3 dB from ‐34.1 dB.
A mini‐traveling wave tube amplifier with super‐low power dissipation for ku‐band user earth stations
Authors: Mita Nagahisa 
Published: July 2007

AbstractA new traveling wave tube (TWT) is realized which can reduce the power consumption significantly in a pulse operation with a small RF duty as a typical operating mode in a small‐scale satellite communication ground station.A method is proposed which estimates the power consumption of a multistage collector by approximating the distribution of the spent beam incident on the collector by a straight line. Based on this method, the collector is made three stages to reduce the power consumption in the RF pulsed operation. It is found that the third collector voltage should be reduced as much as possible. From this result, a TWT with a 40‐W output in the Ku band is realized which has a three‐stage collector with the third collector voltage as low as 80 V. By setting the collector voltage that makes the power consumption minimum under no signal condition, the average power consumption is reduced to only 12 W in a pulse operation with a 1‐percent RF duty.
An m‐times pulse number generating circuit based on switched capacitor bootstrap‐type monostable multivibrator and its application
Authors: Sasaki Hirofumi , Fujimoto Kuniaki , Yahara Mitsutoshi , Ueno Fumio 
Published: July 2007

AbstractAn m‐times pulse number generating circuit is proposed which is made of a monostable multivibrator and an astable multivibrator as well as a gate circuit constructed with a switched capacitor bootstrap circuit and an RS flip‐flop. Since this circuit has the configuration of driving the switched capacitor by the oscillation output from the astable multivibrator, there is no problem of synchronization between the circuits. Since the ratio of the output pulse number to the input pulse number is proportional to the gate voltage of the linearly varying staircase wave, the operation is extremely stable even if the output pulse number becomes large.The output pulse number can be varied significantly by simply changing the value of the capacitor in the time constant circuit in the monostable multivibrator and can be expressed by a simple equation determined only by the circuit parameters. The computed and measured results agree well. By cascading several of these mono‐stable multivibrators, an extremely large pulse number can be obtained easily. If this is cascaded with a 1/n divider, an m/n pulse number can be obtained easily. Further, for a level comparator and a trigger generator in front of the m‐times pulse number generating circuit, the circuit can be used for conversion of the voltage level of the ac signal to the pulse number.
A thin‐film reactor fabricated on an Si‐substrate and its application to dc‐dc converters
Authors: Nishijima Ken‐Ichi , Hidaka Masahito , Yamasawa Kiyohito , Saito Akira 
Published: July 2007

AbstractBy means of integrated circuit (IC) process technology, a monolithic thin‐film reactor was fabricated on a silicon substrate with lamination of a thick‐film conductor and a magnetic thin film. In addition to the fundamental characteristics of the reactor, the dynamic characteristics are evaluated when the reactor is used in a dc‐dc converter. For the buck converter application, the output of more than 2 W with the efficiency of more than 70 percent is achieved.
Columnar structure in anodized porous silicon
Authors: Aoyagi Hidekazu , Motohashi Akira , Kinoshita Akira , Satoh Akinobu 
Published: July 2007

AbstractPorous silicon (PS) anodized below a constant temperature, for example 12°C which depends on anodization parameters, is composed of an assemble of columnar shaped sponge like Si. The width of a column is several micrometers, and columns stand almost perpendicular to Si substrate, and the laterals of columns are in contact with each other directly. The average cross‐sectional area of columns is related to both the boron density in Si substrate and HF concentration in anodization solution, but is not related to both anodization current density and anodization temperature. The average area of a column is determined such like that only one boron atom exists in an atomic layer in a column. In samples anodized at the temperature around and above 12°C, needle and wall‐shaped unanodized crystal Si are observed at the interface between PS columns, respectively.
Reconstruction of magnetic fields by reflection electron tomography
Authors: Matsuda Jin‐Ichi , Otawa Yasuhiko , Nomizu Shigeaki 
Published: July 2007

AbstractThe trend in magnetic record development is toward ever higher areal storage density. Methods for accurate measurement of the magnetic field distribution in the very small region surrounding the gap of the recording head have been the focus of several recent studies. Using transmission electron beam tomography, a new reconstruction technique is proposed and applied to measure three‐dimensional magnetic stray field extending beyond a commercial magnetic head by a developed measurement system. Results have demonstrated the applicability of this technique for measuring a magnetic stray field of several kGauss with an error of less than 10 percent. With transmission electron beam tomography, however, it is difficult to measure directly the magnetic field just beyond the gap of a magnetic head. This is because the stronger Lorentz force of the magnetic field on the electron beam causes the electron beam to collide with the head surface. A new method, called reflection electron beam tomography, is presented herein to overcome the forementioned limitation in which the electron beams are injected perpendicularly to the surface of a magnetic head and their deflection vectors are measured at the deflection plane set above the head. Our method is tested with a known magnetic field model of a one‐turn coil by computer simulation. Results have shown that the magnetic field just beyond the gap of the magnetic head can be estimated with an error of approximately 20 percent.
Whispering gallery mode resonance on an elliptical dielectric cylinder
Authors: Matsubara Mari , Kogami Yoshinori , Matsumura Kazuhito , Tomabechi Yoshiro 
Published: July 2007

AbstractWith a view to application to millimeter wave integrated circuits, we analyze theoretically resonance characteristics of a whispering gallery mode (W.G. mode) propagating along a circumference of an elliptical dielectric cylinder. A wave equation is derived in an elliptic coordinate system and an eigenvalue equation includes Mathieu functions with a large order is obtained. Since this eigenvalue equation is an infinite dimensional determinant, we introduce a new technique to solve the eigenvalue equation. In this determinant, we pay our attention to diagonal elements that affect mainly resonance order. By means of this approach, it becomes possible to estimate a number of approximate terms of the eigenvalue equation to keep an accuracy of a resonance frequency constant even if an eccentricity of the ellipse is increased, namely the ellipse is flatter. It is also possible to find numerically the resonance frequency and electric field distribution of the W.G. mode for the elliptical cylinders with various eccentricity.
A reduced size branch‐line hybrid‐ring using coupled lines
Authors: Nagamine Shinji , Sakagami Iwata 
Published: July 2007

AbstractTo miniaturize the hybrid‐ring, a design method is presented herein for the circuit in which there is an electromagnetic coupling between the transmission lines in folded transmission lines. A 3‐dB branch‐line hybrid‐ring is treated. Analysis is carried out for the two cases of homogeneous and inhomogeneous circuit configurations in which each section has only one coupled line. It is found that in the circuit with a homogeneous configuration, perfect match and complete isolation hold at the center frequency as in the conventional type; additionally, the bandwidth becomes narrower as the coupling becomes stronger. In the inhomogeneous structure where the phase velocities of the even and odd modes are different, there is a shift in characteristics. An equal power division can still be accomplished if the degree of coupling and the phase shift in the coupled lines are appropriately chosen. The overall characteristics differ little from the conventional type. To confirm these findings, an inhomogeneous circuit is constructed and the results are found to agree with the theory.
Circularly polarized absolute value ray vectors in absorbing media&mdash;fundamental relations
Authors: Tokumaru Shinobu 
Published: July 2007

AbstractIn a nondispersive absorbing medium, a geometrical optics field using a complex eikonal is defined. The field is decomposed into two circular polarization components. If the circularly polarized electromagnetic energy fluxes are considered, it is shown that two rays can be defined for the right‐handed and left‐handed circularly polarized field, not in the sense of the energy flux (or the effective power flux), but of the absolute value of the energy flux (or the apparent power flux).This paper presents the basic relationships such as the relationship between the eikonal and the ray vectors and the propagation equations of the ray intensities.
Extended kinetic ising model and its application to magnetization pattern relaxation
Authors: Hayata Kazuya , Higaki Hiroyuki , Koshiba Masanori 
Published: July 2007

AbstractTo analyze the magnetization‐pattern relaxation by the nonlinear dynamical approach, an Ising model in the time‐dependent spin system (kinetic Ising model) is extended to a space‐dependent spin field. By solving the nonlinear diffusion equation on the spin order parameter derived by this formulation, the space‐time evolution of the magnetization pattern can be traced. Specifically, the fifth‐order Ginzburg‐Landau‐type equation in the null applied magnetic field is derived.Two kinds of nontrivial stationary solutions (lump and hole solutions) are presented. The spatial distributions of the stationary solutions are algebraic. Particularly, the lump solution is given as a square root of the Lorentz distribution. From the results of the numerical experiment, it is found that the lump solution is extremely unstable and decays very quickly whereas the hole solution is stable and is not subjected to relaxation. An approximate lump solution for many spatial dimensions is investigated as well.
Electrostatic voltage sensor using surface acoustic waves delay‐line oscillator
Authors: Ishido Masahiro , Xiao‐yan Zhu 
Published: July 2007

AbstractA surface acoustic wave (SAW) electrostatic voltage sensor was fabricated using an SAW oscillator. In the electrostatic voltage sensor, the electrodes to apply electrostatic voltage and produce strain by piezoeffect are not located on the top and bottom surfaces of the substrate but rather on the propagation surface in parallel to the propagation path. Therefore, it is possible to reduce the gap spacing between the electrodes to apply an electrostatic voltage so that the sensitivity can be improved. When an electrostatic voltage is applied, the LiNbO3 single crystal and PZT ceramic were used as substrates in this experiment. The most sensitive crystal plane in a rotated Y‐X plate rotating about the X axis was obtained for LiNbO3 single crystal. It was found the result shows that the 90° rotation Y‐X plate is the best.In the experiment, a 131° rotation Y‐X plate with 20 × 25 × 1.0 mm3 was used which is close to the derived angle and is obtained easily. The interdigital transducer (IDT) electrodes and the electrodes for applying electrostatic voltage were fabricated by Al evaporation. The characteristics of the oscillation frequency versus electrostatic voltage of the sensors were studied. The sensitivity was 0.133 Hz/V and 0.03 Hz/V for the 131° rotation Y‐X plate and a Y‐X plate in the case of LiNbO3. In the case of PZT ceramic, the sensitivity was 12 Hz/V. The dependence of the sensitivity on gap distance between the electrodes for applying electrostatic voltage and on temperature was also studied.
Controllability of gap‐filling for intermetal SiO2 deposition by biased helicon plasma chemical vapor deposition
Authors: Tamura Takahiro , Inoue Youichi , Satoh Makoto , Yoshitaka Hikaru , Sakai Junto 
Published: July 2007

AbstractThe gap between patterned aluminum was filled with SiO2 formed by the reaction of SiH4‐O2 gas using helicon plasma and a biased substrate. The relationship between the SiO2 deposition rate and plasma source power was investigated.It was found that the SiO2 deposition rate was dependent on the rate of SiH4 supply and was independent of the plasma source power. The sputtering rate due to biasing the substrate decreased with increase of the plasma source power. It was found also that the sputtering rate at which void generation is suppressed could be controlled not only by the bias power but also by the plasma source power. Even when the plasma source power and bias power were set at a low level, a sufficient sputtering rate was obtained. The gap‐filling rate (the net deposition rate) was determined by the difference between the raw deposition rate determined by SiH4 supply and the sputtering rate and could be controlled by the plasma source power.