bluuebunny/crossref_metadata_2025 huggingface dataset:
Very high‐speed ROM using bipolar/CMOS technology
Authors: Kurita Koozaburoo , Hotta Takasi , Ueno Masahiro , Hotta Atsuo
Published: July 2007

It is a common practice to realize the internal control of a logic LSI by means of a microprogramming method. A high‐speed operation of this logic LSI requires a highspeed ROM (micro ROM) which stores this microprogram code. This paper proposes a new circuit configuration derived from a combination of bipolar and CMOS technology for a high‐speed micro ROM. In this configuration, the memory cell array is made of MOS transistors while the array periphery consists of a bipolar/CMOS composite circuit in which a high driving capability and a large gm of the bipolar transistor are used so that a high degree of integration and a high speed are attained simultaneously. To confirm the high‐speed characteristic of the proposed circuit, a micro ROM of 2 k words x 64 bits has been fabricated with the 2 μm Hi‐BiCMOS process mixing the bipolar and CMOS structures. The test results of the fabricated device have a minimum read‐out cycle time of 16 ns which is more than twice that of a CMOS circuit having an identical configuration.
Thermomagnetic writing characteristics of holograms on amorphous magnetic films and application to optical matched filtering
Authors: Matsubara Mitsuhito , Saito Katsumi , Kawanishi Kenji
Published: July 2007

Writing and reconstruction of holograms on the amorphous magnetic films have been studied and results of matched filtering of imagery by using the hologram filter have been reported. The resolving power of imagery on thin films of GdTbFe and TbFe is 1800 line pairs/mm. The minimum energy Ew for recording holograms on thin films of GdTbFe and TbFe is 100 mJ/cm2 and 50 mJ/cm2, respectively. Ew of TbFeCo and DyFe films is 3000 mJ/cm2 and 20 mJ/cm2, respectively. First order diffraction efficiency of all holograms is of the order of 10−5 ∼ 10−4 percent. Unknown patterns are recorded on the amorphous film as input imagery. Detection of a desired pattern has been made using the spatial matched filtering method that includes a Fourier transform hologram filter. When GdTbFe and TbFe films are used as the filters, correlation output can be detected through the matched filter with 20 dB signal‐to‐noise ratio.
A realization of monolithic variable integrators and their application to automatically tunable high‐frequency active filters
Authors: Nishio Kenichi , Watanabe Yoshiju , Takagi Shigetaka , Yanagisawa Takeshi , Furihata Makoto , Nagata Minoru
Published: July 2007

With the widespread use of home video and other equipment, it is strongly desired to realize a high‐frequency monolithic IC active RC filter. This paper proposes a method of constructing the integrator with voltage‐controlled current source operated by a single 5‐V supply. Even though operated by a single 5‐V supply, the proposed integrator can realize a wide dynamic range due to an elaboration in the output circuit. For a cutoff frequency of 1 MHz, the maximum input voltage for distortionless output voltage is 1.0 VP‐P. By a simple compensation, an excellent high‐frequency characteristic exceeding 2 MHz is obtained. The proposed integrator is of a variable characteristic with differential inputs, and, consequently, an automatically tunable leapfrog‐type filter can be realized. To evaluate the performance of the proposed integrator, a high‐frequency analysis and a computer simulation were made. The integrator was realized as a monolithic IC by the general‐purpose process for home‐use equipment, and the automatically tunable filter was constructed. The experimental result agreed well with the theory, indicating that the whole filter can be realized by a monolithic IC.
Design of fiber holder for optical fiber‐ribbon splice
Authors: Haibara Tadashi , Matsumoto Michito , Miyauchi Mitsuru , Shirai Masataka
Published: July 2007

A field‐usable optical fiber‐ribbon holder is proposed. Optical fiber ribbon is fixed by placement between wavy plates. The fiberfixing mechanism is analyzed theoretically and experimentally. Optimum fiber‐holder sizes are also investigated. Using this fiber holder, average and maximum fiber‐end displacement of 3.8 and 15μm are obtained. Lowloss splicing of SM fiber ribbon is confirmed, with average splice loss of 0.05 dB.
Influence of arc discharge types on contact resistance of Ag‐Pd alloys
Authors: Sawa Koichiro , Hasegawa Makoto , Miyachi Kunio
Published: July 2007

Different types of arc discharge, that is, steady arc, showering arc or no discharge (initial arc), occur at the break of contacts. These arcs are considered to cause not only contact erosion, but also to affect contact resistance. In this paper, the relation between arc‐discharge types and contact resistance is investigated on Ag, Pd and some Ag‐Pd alloy contacts with Pd content of 30, 50 and 70 wt% by using the automatic data acquisition system of newly developed contact resistance. The following can be made clear. Under no discharge and showering arc discharge, contact resistance is always low at any Pd content. However, under steady arc discharge, contact resistances of the contacts with Pd content more than 50 wt% remain low and those of Ag and of AgPd30 become high. From the results of the approximation of distributions of the measured contact resistances with Weibull distribution function, it can be stated that the calculated location parameter RO gives the approximate value of constriction resistance and the scale parameter Rα gives that of film resistance. On the other hand, the observation of contact surfaces reveals the relation between contact resistance and surface conditions. Also, the differences of arc duration or discharge voltage waveforms according to Pd content are recognized. They are considered to influence surface conditions or contact resistance. A physical model that describes these phenomena is proposed.
A new two–dimensional process simulation system HITOP
Authors: Onga Shinji , Kato Kohichi , Taniguchi Kenji
Published: July 2007

A new two–dimensional process simulator HITOP is developed which can handle oxidation, diffusion, and ion implementation processes. This simulator can be used for process design of practical scaled MOS basic circuits and has the following characteristics: (i) the region of a size from a few μm to a few tens μm containing multiple MOS devices can be simulated simultaneously; (ii) the variation of the layered film formation during the process can be recognized; (iii) a highly accurate simulation is possible from the viewpoint of physical chemistry modeling and of numerical algorithms; (iv) a bidirectional interface with the shape simulator is contained. It is possible to accept the shape of the etching and deposition processes, continue execution, and return the shape data after the process to the shape simulator. For the benefit of the user, changes of the shape of the junction during the process, situation of the growth of the oxide film and the modification of the top layer are displayed successively so that the basic information for circuit design is provided. The present system can be used with a layout processor and a device simulator.
High stable SAW devices on LST cut of quartz
Authors: Watanabe Takaya , Shimizu Yasutaka
Published: July 2007

Recently, 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 this paper.
Tunable laser using sheet of dye‐doped plastic fibers
Authors: Muto Shinzo , Ando Akitoshi , Yoda Osamu , Hanawa Takayuki , Ito Hiroshi
Published: July 2007

The 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 N2 laser, 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 covered.
Multiusable printing characteristics of dye transfer sheets
Authors: Taguchi Nobuyoshi , Imai Akihiro , Matsuda Hiromu , Yubakami Keiichi
Published: July 2007

Dye transfer‐type thermal printing systems have been developed that yield full color prints with excellent tone and color reproducibility. However, utilization efficiency of the recording materials has been poor. Therefore, an experimental evaluation of the materials and the structure of the dye transfer‐type thermally sensitive sheets (dye transfer sheet and color receiving sheet) was performed. It was found that an economical n‐multiple utilization mode printing system, in which the relative speed of the dye transfer sheet to the color receiving sheet is maintained at 1/n (n ≥ 1), can be realized.

The dye transfer sheet is composed of a base sheet and a coloring material layer. The base sheet is thermally stabilized by adding a heat resisting and slipping layer on the back of the sheet. The coloring material layer is composed of a dye, adhesive resin and spherical thermal resin spacers. A color developing layer, which contains a heat resisting and slipping UV sensitive color developing resin, is added to the surface of the color receiving base sheet. In the printing experiment, the dye transfer and color receiving sheets were moved by using the surfaces of spacer particles and the coloring material layer.

This printing system showed stable operation at n = 12, where the printing density was independent of n. It was found that this method provides a better printing density than the system in which printing is carried out for N times at a constant speed (n = 1).
A method of nonimpact braille printer by electro‐thermosensitive process
Authors: Yonezawa Yoshimichi , Itoh Kazunori , Hattori Hiroshi
Published: July 2007

A method of recording braille patterns directly from an electrical signal is studied and its possibility investigated. The method consists in localized electrical conduction in response to the image signal on a sheet which has conductivity and thermal foaming sensitivity. By means of the joule heat generated, small dots with the maximum height of 0.5 mm are formed on the sheet surface to create the equivalent of paper brailles. A thermally sensitive swelling capsule for swelling agents and tin oxides for conductivity are combined in a sheet. The optimum conditions for the composition and the recording method have been found so that a fundamental possibility of generating contact‐resistant brailles is demonstrated which has a low recording noise and a simple recording mechanism.
Development of a high‐reliability flip‐chip packaging reinforced by resin
Authors: Soga Tasao , Nakano Fumio , Fuyama Moriaki
Published: July 2007

A high‐reliability chip‐on‐board (COB) technique using the flip‐chip method to mount a driver LSI on a soda‐glass substrate has been developed. By forming a flip‐chip structure in which both the chip and the gap between the chip and the glass substrate are filled with resin, the thermal fatigue life can be one order of magnitude longer than that of a device with an exposed flip‐chip structure. The extension of the device life is due mainly to the relaxation of stress to the device by matching the thermal expansion coefficients of the resin and the solder. Furthermore, using the resin‐filled flip‐chip structure, the breakage of glass at the pedestal section is minimized. The COB package is highly reliable and durable against humidity.
High‐speed and high‐accuracy CMOS LSI for document image signal processor
Authors: Tadauchi Masaharu , Nakashima Keisuke , Nagai Kenji
Published: July 2007

A signal processing circuit was created on a one‐chip CMOS LSI in which the document image is read by a line sensor and is converted to digital signals. The present LSI, which corrects various distortions contained in the image signals accurately at a high speed, can handle a high‐speed image signal processing (with 5M picture elements/s maximum) and hence can be applied to an ultra‐high‐speed G4 facsimile. A high‐speed operational amplifier and a high‐speed comparator needed for one‐chip realization are used. Especially, for improvement of accuracy of the CMOS operational amplifier, the automatic offset cancelling system has been developed so that the process of the analog input signal of several hundred millivolts from the sensor can be accomplished. In the present LSI, the CMOS process of 2.5 μm rule is used and the chip size is 6.8 × 7.5 mm.
Examination of picosecond GaAs HEMT photodetector
Authors: Umeda Tokuo , Cho Yoshio
Published: July 2007

The optical response speed of a GaAs MESFET photodetector with an HEMT structure was measured via a correlation method. A high optical response of a full width at half‐maximum (FWHM) 18 ps was obtained. This response speed includes the contribution of the FWHM of the pulse used in the measurement. To estimate the response speed characteristic to the device, the obtained response speed is divided into the portion due to the carrier transit time and that due to the stray capacitance. From the studies of both of these contributions, the contribution by the optical pulse was separated. As a result, the response speed characteristic to the device is estimated to be 12 ps. Also, it is found that the response speed can be reduced to about 8 ps by the reduction of the gate width.
Approximate theory and characteristics of laser doppler velocimeter using self—mixing effect of semiconductor laser diode
Authors: Shinohara Shigenobu , Yoshida Hirofumi , Shimizu Edson Toshiaki , Sumi Masao
Published: July 2007

To explain the experimental characteristics of a laser Doppler velocimeter using the self‐mixing effect of a semiconductor laser diode (LDV) with a rotating disc as a target, a theoretical analysis of a Doppler beat waveform was carried out, and its approximate solution was obtained by using the perturbation method. The theoretical characteristics based on this solution agreed fairly well with the experimental ones. The operating conditions of the LDV required for forming the beat wave into a sawtooth waveform, and the reasons why the sawtooth wave is transformed into a mirror image depending on the sign of the Doppler frequency were found, i.e., the phase angles of the second and third higher harmonics of the beat wave are inverted by the inversion of the direction of rotation. The upper limit of the Doppler frequency and the range of R parameter of the LD were estimated theoretically.
Finite—element solution of three—dimensional resonator problems. Novel tetrahedral element
Authors: Hano Mitsuo
Published: July 2007

A new tetrahedral element is proposed for the finite element analysis of a three‐dimensional resonator problem. It has been reported that in finite element analysis with the conventional tetrahedral elements, nonphysical spurious solutions are generated. In the tetrahedral element proposed here, only the components of electric or magnetic field along the element surface are used as unknown parameters. It is shown that there are many zero eigenvalues in the finite element expression obtained by the new tetrahedral elements. It is demonstrated that the matrix in the new method can be regularized with the eigenvectors corresponding to the zero eigenvalues so that a substantial reduction of the unknown parameters can be realized. The regularization process is purely mathematical. No eigenvalues and eigenvectors are altered. From the eigenvalues obtained from actual numerical calculations for a resonator, it is shown that several of the smaller ones correspond to the resonant modes, and no spurious solutions appear. A feature of the present method is that the spurious modes can be eliminated and the number of unknown parameters is reduced substantially. The method is expected to be an effective analysis method for finite element solutions of three‐dimensional resonator problems.
Phase—synchronous–type walsh analyzer using switched—capacitor circuit
Authors: Sasaki Itsuo , Yoneda Shojiro , Kasai Tamotsu
Published: July 2007

The Walsh transformation is a useful method which can replace the Fourier transformation for analysis of alternating‐numbers, and is suitable for digital waveform analyses. Since this is a binary transformation, its hardware realization is achieved easily. Using this advantage, this paper proposes a discrete Walsh‐transformation circuit using a switched‐capacitor circuit. This paper also proposes a solution of a problem of the change of power spectrum due to the phase‐shift of the input signal which prevents practical applications of the Walsh transformation to an electronic circuit. In the proposed circuit, a Walsh‐function wave based on a rectangular waveform synchronized with the input signal is formed, and this is used for the clock of the switched‐capacitor discrete Walsh‐transformation circuit. This arrangement makes the signal‐detection period variable so that the signal is always processed with no phase shift. This arrangement itself is also suitable for a switched‐capacitor circuit. A prototype switched‐capacitor discrete Walsh‐transformation circuit (for 32 sampling points) was made with discrete components. The results confirm that the proposed method is effective for analyzing rectangular waves.
Formation of (Hf·Ti)C film on cemented carbide tools by low—pressure chemical vapor deposition
Authors: Fuyama Moriaki , Hanazono Masanobu , Ura Mitsuru , Honda Haruhiko
Published: July 2007

The optimum deposition conditions of (Hf·Ti)C film on cemented carbide tools using low‐pressure chemical vapor deposition are discussed here based on evaluations of the physical and mechanical properties of the deposited films.

The film composition could be controlled through the flow rate of titanium and hafnium iodides and the film formed had a Vicker's hardness of 2500 to 3000 kg/mm2. The wear resistance of the (Hf·Ti)C coated tool was as high as that of the previously developed HfC coated tool. The grooving wear of the (Hf·Ti)C coated tool was higher than that of the TiC coated tool. This was attributed to the larger thermal expansion coefficient of the (Hf·Ti)C film compared with those of TiC and HfC.
Fiber misalignment measurement method using one—directionally observed image
Authors: Ide Atsushi , Tachikura Masao
Published: July 2007

This paper investigates the measurement method of optical fiber offset in two directions by one‐directionally observed image. This method employs the transmitted illumination and the bright lines of the intensity distribution due to the lens effect of the fiber are used to observe the position. The method is advantageous because of a simple mechanism for its realization. The observation principle of fiber position is investigated based on computer simulation and experimental results to clarify characteristics of the method. The real measurement of the fiber offset and its precision is investigated for fusion mass‐splicing, to which the present method is very suitable. Employing this method, the standard deviation of 1.3 μm is achieved in precision of the measurements of the fiber offset. The screening characteristics for a given offset are also evaluated.
Design method of general‐purpose and high—speed digital correlator LSI
Authors: Morikura Masahiro , Enomoto Kiyoshi , Kato Shuzo
Published: July 2007

This paper proposes a construction of a general‐purpose high‐speed correlator LSI, aiming at applications to various problems such as digital signal processing and synchronization word detection. A general method of constructing the rearrangement circuit as well as the generation of a highspeed detection pulse are presented, and are. important in the construction of a highspeed synchronization word detector, one of the major applications of the high‐speed digital correlator. It was shown by experiment that the developed general‐purpose high‐speed digital correlator has the feature that the parameters can be set in a flexible way according to the problem, and can operate up to 200 MHz by the one—chip structure (two‐parallel processing).
Biopolar—voltage–controlled optical switch fabricated on Z—cut Ti:LiNbO3 intersecting waveguides
Authors: Nakajima Hirochika , Sawaki Ippei , Seino Minoru , Yamane Takashi
Published: July 2007

A new optical switch is proposed in which attention is paid to the behavior of the guided wave at the crossing of an intersecting waveguide. Design and fabrication of an optimal configuration were carried out at a practical wavelength of 1.3 μm. For the analysis of the operating mechanism and the optimum design, a waveguide analysis method based on the Fourier transform developed originally has been used. By means of the electrodes formed via a buffer layer on a Z‐cut Ti:LiNbO3, a bipolar optical switch was fabricated in which switching is possible in both the positive and negative polarities. This switch has a low loss and low crosstalk if the intersection length is short, although the operating voltage is high. If the device length is increased for reduction of the operating voltage, other characteristics are degraded. Therefore, it is necessary to diffuse the double Ti layers below the electrodes and to improve the electrode structure. In the device with an intersection length of 8 mm thus obtained, the operating voltage of 14 V was realized. By way of theory and experiment, the characteristics of this switch were understood and the guideline for the future applications was obtained.
OEIC photoreceiver using InP system with a 5–V source voltage supply
Authors: Tojo Masaaki , Matsuda Kenichi , Kubo Minoru , Sibata Jun
Published: July 2007

A PIN/JFET using an InP‐based material for receiving an optical signal at a wavelength of 1 μm has been developed. From a practical viewpoint, operation using a single power supply is desirable. In this study, an opto‐electric integrated circuit (OEIC) composed of a PIN/PD, JFET, feedback resistor, etc., was fabricated on a semi‐insulating substrate and then the characteristics of each component were evaluated. The pinchoff voltage and cutoff frequency of the JFET were 1.2 V and 900 MHz, respectively. The transimpedance in operation was 965 ft, which was almost the same as the feedback resistance. When the power supply voltage was 5 V, the 3‐dB cutoff frequency was 220 MHz, indicating that operation using a single power supply is feasible. The 1/f noise of JFET was 20 nV √Hz and the receiver sensitivity was −24.1 dBm. High reliability could be ensured by employing a 50‐hr THB screening test.
Optogalvanic effect on a hollow cathode He—Cd+ laser
Authors: Fuke Akira , Masuda Katsuhiko , Tokita Yasuhiro
Published: July 2007

A hollow cathode He—Cd+ laser simultaneously emits three primary colors. Therefore, a white color laser beam is emitted from this laser. This paper describes the optogalvanic effect and the results of our measurements under the study of stabilization of the white light laser. In the measurement, the colors red, green or blue were monochromatically emitted and the change of the anode voltage was measured in accordance with laser optical power by turning the optical path in the resonator on and off. The optogalvanic signal was noticeable when the color red or blue was emitted. However, almost no effect was observed during emission of the color green. The optogalvanic signal during emission of the color blue depends not only on the optical intensity, but the beam diameter. This indicates that the optogalvanic signal during emission of the color blue is dependent on the change of the cathodic effect. On the other hand, the gain distribution of blue in the bore is presumed to reach the neighborhood of the cathode surface. During emission of red, the optogalvanic signal is proportional to the light intensity, regardless of the beam diameter. It is understood that the optogalvanic effect during red color emission is caused by the change of the He+ population which is distributed at the center of the bore and is the origin of the red color emission.
Amorphous—silicon thin—film transistors and their integrated circuits
Authors: Uchida Yasutaka , Oda Shunri , Matsumura Masakiyo
Published: July 2007

Since the technology to integrate amorphous‐silicon thin‐film transistors on a large area glass substrate is a key to realizing a flat panel display with high capacity, high resolution, and full color, it has been developed extensively in industry research organizations worldwide. Attempts have also been made to apply them for sensing devices and printing devices. The amorphous‐silicon thin‐film transistor is becoming central to man‐machine interface devices, and the improvement of its performance has become important. This paper introduces these technological trends with emphasis on our own research results.
Relationship between the contact resistance and the temperature near electrical contacts switching continually
Authors: Kubono Takayoshi , Teraoka Shinji
Published: July 2007

The temperature increase of electrical rays is regulated by the electrical component regulatory law. There are few examples of measurement of temperature characteristics during the multiple open and close operations at the electrical contact of a small relay. In this paper, the resistive load circuit of dc 30 V to 10 A was open for 2 s and closed for 1 sa total of 100,000 times. During each closing period, the contact resistance, the temperature near the electrical contact, the temperature of the interior wall of the relay case, and room temperature were measured and correlated. The temperature near the electrical contact depends strongly on the contact resistance and increases or decreases with several cycles of delay in the open and close cycle for the increase and decrease of the contact resistance. The contact resistance for 1000 continuous measurements and the average of the temperature increase (difference between the temperature near the electrical contact and the room temperature) are proportional to the correlation factor of more than 0.95. When the temperature increases between the contacts with and without through‐holes are compared, it is seen that the increase due to thermal radiation was smaller at the through‐hole when the contact with through‐holes is used. From these experimental results, the typical temperature characteristics of the electrical contact as a principal functional device were clarified.
Spatial resolution in NMR fresnel transform imaging
Authors: Yamada Yoshifumi , Hayashi Takehiko , Tanaka Kunio , Abe Zenmonn
Published: July 2007

There have been no reports of papers which studied thoroughly and quantitatively the relation between the spatial resolution and the imaging parameters in the Fresnel transform technique. This paper describes the relation between the spatial resolution and the imaging parameters in the Fresnel transform technique. The experimental results are shown to be in good agreement with the theoretical estimations. Moreover, the theoretical consideration shows that a localized imaging is possible without using any localization technique if the scanning of the characteristic field is limited to a local region. An experimental result on the local imaging is presented. The results obtained in this paper show that the Fresnel transform technique has a great promise as a new NMR imaging method.
Copper‐polyimide interaction during imidization process of polyamic acid solution to polyimide
Authors: Miura Osamu , Miyazaki Kunio , Numata Shunichi , Watanabe Hiroshi
Published: July 2007

A polyimide film cured on a copper wire was found to contain a large amount of Cu. The cause of the Cu contamination was investigated. As a result of the investigation, it was confirmed that Cu is ionized by the carboxyl group which is bonded to the benzene ring in polyamic acid and is dissolved into the varnish. When Cu which is dissolved into varnish, partially oxidized during heating at 300°C, it precipitates in a polyimide film and forms an aggregated body.
Analysis of the waveguide with loss or gain by the finite‐element method
Authors: Matsuhara Masanori , Angkaew Tuptim
Published: July 2007

In the past the finite‐element method with a variational formulation has been used for numerical analyses of the propagation characteristics of electromagnetic waveguides. However, this method based on the variational representation is not applicable to waveguides with losses or gains.

This paper derives a generalized Galerkin equation which is established for waveguides with losses or gains. The finite‐element method is proposed based on this Galerkin equation. As examples of numerical calculations, a waveguide loaded with a lossy dielectric, a helical waveguide and a microstrip line were analyzed.
Finite‐element solution of three‐dimensional periodic waveguide problems
Authors: Inoue Kazuhiro , Hayata Kazuya , Koshiba Masanori
Published: July 2007

With a view to developing a method enabling derivation of the propagation characteristics of a three‐dimensional (3‐D) periodic waveguide with an arbitrary shape, an analysis technique based on the finite‐element method with tetrahedral elements is proposed and its formulation developed. For the finite‐element analysis of the electromagnetic field in a 3‐D inhomogeneous region including a dielectric material, the variational expression in terms of three components of magnetic field is convenient. However, if the conventional variational expression is used directly for solving eigenvalue problems, spurious solutions can appear. In this paper, to suppress and eliminate these spurious solutions, various countermeasures to spurious solutions, developed for the finite‐element analysis of a waveguide uniform in the propagation direction that can equivalently be treated as a 2‐D problem. These include: the penalty function method, the transverse magnetic‐field component method and the reduction method, all of which are extended to the finite‐element analysis of 3‐D periodic waveguide problems. Specifically, by way of the numerical examples for a rectangular waveguide loaded with dielectric material with a periodic structure, the validity of the proposed method and the adaptability of each method for suppressing and eliminating spurious solutions are investigated.
High‐frequency monolithic differential input/output integrator
Authors: Takagi Shigetaka , Fujii Nobuo , Yanagisawa Takeshi
Published: July 2007

The high‐frequency monolithic integrator proposed by the authors in [1] has excellent frequency characteristics because it does not require pnp transistors which have poor high frequency characteristics. In addition, since the time constant can be changed electronically, it is also suited as an active element for monolithic automatic tuning filter using a PLL. However, since this integrator is a balanced‐type one, a circuit converting the signals from the unbalanced type to the balanced type is needed. Therefore, the chip area and power consumption will increase.

This paper points out that the integrator using the balanced negative impedance converter (NIC) proposed in [1] can be used as the differential input/output integrator for an unbalanced input since the circuit is superior in the common mode rejection ratio. Also, the method for varying the time constant is improved and the circuit is simplified so that the frequency characteristics are improved further. Problems on the reduction in the variation range of the time constant and on the variation of the dc potentials are relaxed by the appropriate determination of element values, and the circuit technique, respectively. The proposed integrator is made as a monolithic integrated circuit by the 3‐μm bipolar process. Experiments of a third‐order low‐pass filter with the cutoff frequency of MHz are carried out to confirm the practicality and effectiveness of the proposed integrator.
Study of BiCMOS cache memory
Authors: Kurita Kozaburo , Hotta Takashi , Maejima Hideo , Hotta Atsuo
Published: July 2007

To improve the speed of the processors for CPU of minicomputers and other systems, it is required to improve the machine cycle and the memory cycle, which are the performance indexes of the system. The general idea to realize a high‐speed memory cycle is to apply the cache memory, which provides a hierarchical structure for the memory. This paper considers the realization of the cache memory by Hi‐BiCMOS (high‐performance bipolar CMOS) technology, which aims at a high‐speed, highly integrated LSI by combining the microstructured CMOS and high‐speed bipolar devices at the element level of the circuits. As the basic circuit, a RAM‐combined Hi‐BiCMOS circuit comparator is proposed, where the comparator logic is introduced into the sense amplifier of RAM. Applying the proposed circuit, TLB (Translation Lookaside Buffer) is designed and constructed, which performs the address transformation by cache memory. A satisfactory operation of the circuit was verified with the address conversion time of 13.3 ns. An evaluation by simulation was made for applying the proposed circuit to a 4K Byte cache memory, and it is indicated that the cache access through an address conversion can be made in 17.5 ns.
Three‐dimensional electromagnetic analysis of a vacuum window involving waveguides
Authors: Nakatsuka Hirotaka , Yoshida Norinobu , Fukai Ichiro
Published: July 2007

Local heating of the pillbox‐type vacuum window employed in microwave heating of nuclear fusion apparatus TOKAMAK has been a problem when used under a high power, particularly under the ghost mode. This factor is used to determine the maximum power of the heating system. However, in the measurement in actual operation, only the electric field can be measured when the amplitude and reflection coefficient become small due to the loss. An analysis taking into consideration the dielectric loss is needed to determine the characteristics of the electromagnetic field distribution in the ghost mode. We have applied the spatial network method to the pillbox vacuum window excited by a rectangular waveguide. The method has a number of unique features as a time domain analysis method for three‐dimensional electromagnetic fields. After the basic treatment is described, the electromagnetic field of the ghost mode is simulated by the analysis taking into consideration the dielectric loss. The effectiveness of the three‐dimensional electromagnetic analysis for the entire system is presented.
All‐NbN nanobridges for DC‐SQUID application produced by field emission
Authors: Nagaoka Shiro , Hamasaki Katsuyoshi , Irie Akinobu , Yamashita Tsutomu , Kougo Masanori
Published: July 2007

This paper describes the method for producing a nanobridge‐type SQUID, the LsIo/ϕOratio of which can be regulated to an optimal value at the liquid He temperature (4.2 K), and the properties of the SQUID. An epitaxial NbN film is produced by the reactive RF magnetron sputtering method for use as the electrode material, and an MgO film, which is thermally stable, is used as the insulating barrier. The Josephson nanobridges are formed in MgO film of the NbN/MgO (5‐10 nm)/NbN junction of about 4 × 4 μm2in area by field emission in the liquid He environment. The junction resistance before the application of electric field is very high, that is, 1 MΩ or higher. Needless to say, Josephson current is absent in the junction. The critical current can easily be regulated to a desired value by varying the applied voltage. The produced SQUID exhibits a high stability to the heat cycle test (300 K‐4.2 K) which is carried out 50 to 60 times for about 2 years.
Analysis of microstrip‐magnetostatic wave resonators
Authors: Tsutsumi Makoto , Takeda Tomoyuki
Published: July 2007

This paper analyzes a microstrip‐type magnetostatic wave resonator made of a YIG film loaded with a metal disk. First, based on a simple model consisting of a magnetic wall at the edge of the disk, the relationship between the resonant frequency and the aspect ratio and the Q value was investigated. Next, a more realistic model is set up and analyzed by the mode matching technique. The relationship between various resonator parameters and the energy trapping situation of the magnetostatic wave in the disk is found. Also the distribution of the RF magnetization in the disk is presented.
Fiber‐optic phase modulator using piezoelectric copolymer coating
Authors: Imai Masaaki , Odajima Akira
Published: July 2007

An optical fiber was coated with vinylidene fluoride/trifluoroethylene piezoelectric copolymer (P(VDFx/TRFE100‐x), x = 73 mole%) to a thickness of 85‐100 μm via extrusion method. To create peizoelectricity, this fiber was processed to have polarization in the radial direction by corona discharge poling and was used to construct a fiber phase modulator; ac/dc voltages were applied to concentric cylindrical electrodes attached to the optical fiber and phase shifts were investigated in relation to the applied electric field. The wavelength characteristics of phase modulation sensitivity were measured in a wide range of 20 Hz to 50 MHz. The phase modulation sensitivities were 2.1 × 10−5 rad/(V/m)/fiber length (m) in the low‐frequency range and 3.5 × 10−6 rad/(V/m)/m in the high‐frequency range. At frequencies higher than 1 MHz, resonances in the fiber‐jacket composite were observed clearly. Next, to explain the phase modulation characteristics, the theoretical investigation of a two‐layer model from silica glass and piezoelectric copolymer coating was carried out.
Full vectorial finite‐element formulation for anisotropic waveguides with complex permittivity tensor
Authors: Hayata Kazuya , Miura Kazunori , Koshiba Masanori
Published: July 2007

An efficient computer‐aided solution method based on the vectorial finite‐element method is developed for solving arbitrary waveguiding structures containing anisotropic materials with complex permittivity tensor. In this scheme, a formulation in terms of the transverse magnetic field component is adopted and the eigenvalue of the final matrix equation corresponds to the propagation constant itself. Thus one can avoid unnecessary iterations which arise when using complex frequencies. To demonstrate the strength of the present method, numerical results are shown for a rectangular waveguide filled with a lossy anisotropic dielectric with off‐diagonal elements in a permittivity tensor.
Simulation of low‐noise inductance with high‐Q
Authors: Nakamura Masataka , Okine Mitsuo , Shigehiro Takanori , Ishizaki Tatsuya
Published: July 2007

A number of methods have been proposed for LC simulation due to its inherent low sensitivity as a doubly terminated lossless reactance circuit [1 ‐ 8]. A direct simulation of L is effective since it has a one‐to‐one correspondence with the circuit parameters and is applicable to cases other than filters. The method is advantageous over the passive inductance since the active device such as a transistor or an operational amplifier can simulate an inductance with a large L value and a high Q. However, the noise is larger than that in a passive structure and hence reduction of noise is an important subject. This paper proposes a circuit which realizes a simulated low‐noise and high‐Q inductance with one transistor and one operational amplifier. In noise analysis, a low‐noise design is presented with the introduction of the noise factor. Further, the effect of imperfection of the active device on the L and Q values, and the signal level in the circuit are discussed in detail.
An analysis of scattered near field and induced current of a beam wave by pits on optical disk using boundary element method
Authors: Manabe Katsuya , Miyazaki Yasumitsu , Tanaka Takaaki
Published: July 2007

Numerical analysis of the scattering of a beam wave caused by pits which are assumed to be absolute conductors is carried out in order to obtain the optimum shape of pits and pregrooves and achieve high density on an optical disk. For analysis, the boundary element method (BEM) is used because it is adaptable to any shape of pits and pregrooves and any type of incident beam. For rectangular or trapezoidal concave and convex pits, scattered fields and induced currents are calculated as functions of the angle of the pit wall and track pitch, and comparison between the two is made. In the case of convex pits, it is found that the minimum track pitch without crosstalk for E‐wave and H‐wave are 2w and 1.8w (w: the spot size of the incident beam), respectively. As the pit shape is changed from rectangular to trapezoidal, the intensity change of the main lobe with or without the pit is small. Finally, the current density on the disk, which is induced by scattering, is calculated.
Electroluminescence from anodized tantalum pentoxide thin films
Authors: Miyairi Keiichi , Hanawa Ikuo
Published: July 2007

To understand the electric breakdown characteristic of anodized tantalum pentoxide (Ta2O5) films, the electroluminescence phenomenon was investigated in the electric field ranging from low field to the breakdown field. Since the luminescence is weak, it was detected by using a photomultiplier tube and a lock‐in amplifier.

The luminescence was independent of temperature but was strongly dependent on the applied voltage. When the electric field was slightly lower than the breakdown field, the luminescence due to the carrier injection based on the Schottky effect was observed. When the electric field was close to the breakdown voltage, luminescence due to the electron avalanche was observed, where the luminescent spectrum had a peak at 600 nm.

These observations indicated that the electric breakdown is related to the electron avalanche.
A continuously calibrating charge redistribution A/D converter
Authors: Nakano Motohiro , Tsukamoto Kousuke , Miyata Takeo , Saitoh Takayoshi
Published: July 2007

This paper describes a self‐calibrating A/D converter (ADC), which continuously obtains calibration data for the error of circuit elements and carries out self‐calibration using these data in A/D conversion. This ADC is able to maintain a highly accurate conversion for a long time by renewing the calibration data continuously. By subdividing the calibrating operation and distributing the operation among the conversions, a lowering of conversion speed which is due to the calibrating operation can be reduced. On the assumption that the calibration data are destroyed or circuit parameters are varied by drift, conventional self‐calibrating ADC and this ADC are simulated and experiments are carried out by breadboard circuit. Consequently, it is verified that the conventional self‐calibrating ADC is not capable of maintaining highly accurate conversion for data destruction and drift. On the other hand, the continuously self‐calibrating ADC is able to recover the conversions, accuracy after several tens conversion cycles for data destruction and maintain highly accurate conversion against variation of circuit parameters due to drift.
Merged bipolar transistor models including the substrate current
Authors: Inohira Susumu , Shinmi Toshio , Higuchi Hisayuki , Iida Kyoichi , Ohkawara Hiroshi
Published: July 2007

High integration density and high‐speed operation are obtainable by miniaturization of bipolar LSI devices. In modern bipolar integrated transistors, an undesired current flows into the substrate due to the parasitic sub‐PNP transistor. For example, for Bi‐CMOS circuits, this substrate current can be the main cause of reduction in the supply voltage.

This paper proposes merged models for the NPN and lateral PNP transistors which include the substrate current due to the parasitic sub‐PNP transistor. The extraction of model parameters for the calculation of substrate current is also described. By the application of these models to the simulation of NPN transistor for Bi‐CMOS memory and lateral PNP transistor of linear process, good accuracy of dc saturation and substrate current characteristics can be obtained. Its application to the simulation of decoder/memory cell of Bi‐CMOS memory is demonstrated.
New air‐gap‐type piezoelectric resonator supported by thin films from the surface
Authors: Yamanouchi Kazuhiko , Oba Masaki
Published: July 2007

In a piezoelectric resonator supported by a thin film with an air gap between the substrate and the resonator, it is difficult to construct a resonator because of the stress in the resonator. Stress also affects the electrical properties in this device. In this study, stress is minimized by using (1) a structure supported at one end, and (2) a surface‐supported structure. Piezoelectric resonators supported by a thin film with an easily constructed structure were proposed. In device (1), the resonant frequency, the quality factor Q and the capacitance ratio γ were 300 MHz, 1200 and 54, respectively. In device (2), the resonant frequency, Q and γ were 1.77 GHz, 300 and 250, respectively. Breakage of the thin film with a small air gap and stress in the film will be discussed. Finally, the usefulness of this method will be proved.
A 256‐K 13‐nanosecond CMOS SRAM
Authors: Asahina Katsushi , Murakami Shuji , Ichinose Katsuki , Minami Fuyumi , Funakoshi Yasuhiro
Published: July 2007

Recently, many types of very high‐speed static RAMs (SRAM) using CMOS or BiCMOS technologies have been announced. Even with CMOS SRAMs, which operate in the range of 10 ns access time, both device and circuit technologies and also usage and reliability problems become prominent, and must be solved in order to achieve adequate speed performance.

This paper discusses technical problems and their realistic solutions for achieving very‐high speed SRAMs using CMOS from the viewpoint of device and circuit technologies. Consequently, short channel MOSFETs using 1.0 μm NMOS and 1.0 μm PMOS gate lengths were used to reduce the access time. In order to reduce the soft‐errors that cause problems when high‐speed SRAMs are operated with a short cycle time, theVthof memory cell transistors is set higher than the level in the other circuits. Hence, the soft‐error rate is the same when the device is operated with a longer cycle time.

With respect to circuit technology, a high sensitivity sense amplifier is used with a smaller gain decrease under low voltage, a circumstance which is suitable to high‐speed SRAMs that are sensitive to supply voltage bounce due to electrical noise within the chip.

In order to implement systems using high‐speed SRAMs, a write‐timing control circuit is introduced, which alleviates the timing constraints on the address skew during write timing. Utilizing these technologies with a CMOS process, a 256‐K SRAM with an access time of 13 ns has been achieved.