ITE Technical Report
Online ISSN : 2424-1970
Print ISSN : 1342-6893
ISSN-L : 1342-6893
25.6
Showing 1-22 articles out of 22 articles from the selected issue
  • Type: Cover
    Pages Cover1-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Type: Index
    Pages Toc1-
    Published: January 29, 2001
    Released: June 23, 2017
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  • Eichi KAWANO, Toshiaki MATSUNAGA, Kazuyoshi OGATA, Hirokazu IWASAKI, K ...
    Type: Article
    Session ID: BFO2001-1/ROFT2001-1
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Mobile telecommunications such as portable telephones are important roles in information societies. There are, however, many shelters like walls, which affect electromagnetic wave propagation in underground streets or inside of buildings. Those problems must be solved to use mobile equipment comfortably. Electromagnetic waves more decrease in tunnels than free space, especially at the direction of the bents and branches. FVTD method and ray tracing method are applied to the numerical analysis of electromagnetic waves propagating in two-dimensional tunnels, which have crank branches using a line source in this paper. We compared the numerical results of those two methods. In addition, we measured the electric field distribution when we assumed that the line source is in a arbitrary position and compared them with the numerical results of FVTD and ray tracing methods.
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  • Kazunori UCHIDA, Masao UEMURA, Souichirou Tajima, Chang-Kwon LEE
    Type: Article
    Session ID: BFO2001-2/ROFT2001-2
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    This paper is concerned with a numerial analysis of electromagnetic wave scattering by a convex or concave cylinder based on the ray tracing method. First, the electromagnetic wave scattering by a conducting strip is considered, and image coefficient for 2D problem is introduced by using Fresnel function. It is numerically demonstrated that the scattered field in the reflected region computed in terms of the image coefficient is in good agreement with the Wiener-Hopf solution when the strip width is larger than the wavelength. Second, the present method is applied to the electromagnetic wave scattering by the convex cylinder such as circular and rectangular conducting cylinders. Third, this method is also applied to the concave cylinder such as corner and parabola reflectors. Finally, some numerical examples are also given for RCS of 2D problems.
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  • Kenta NAKASHIMA, Jiro IWASHIGE, Tomoya UEDA
    Type: Article
    Session ID: BFO2001-3/ROFT2001-3
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    In recent years, mobile communication has been used with remarkable progress. The estimation of the electric wave propagation routes in the urban areas is a matter of importance. In this paper, we analyze the electromagnetic fields that reach an observation point by way of fences on a rooftop of building. The analysis is carried out by GTD. We show some numerical examples about the influence on the electromagnetic wave propagation by fences on a building rooftop.
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  • Naoki YASUTAKE, Takayuki TANAKA, Eisuke NISHIYAMA, Masayoshi AIKAWA
    Type: Article
    Session ID: BFO2001-4/ROFT2001-4
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    The oscillator with many active devices using higher mode of planar circuits for power combinig of microwave/millimeter wave band were investigated. For the fundamental study, configuration of the oscillator with TM_21 mode of circular resonator and Gunn Diode have been studied. In experiments at X-band for the oscillator with one element or two elements, power of two elements case has obtained about two times that of one element. As a result, the power combining method proposed here is confirmed both experimentally and theoretically.
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  • Kosuke TSUJI, Kenji KAWAHATA, Takayuki TANAKA, Eisuke NISHIYAMA, Masay ...
    Type: Article
    Session ID: BFO2001-5/ROFT2001-5
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Using the thee-Dimensional MMIC topology, miniaturized microwave/millimeter-wave integrated circuits have been investigated. Before, QD-TFMS lines(Quasi Distributed TFMS lines)composed of TFMS lines and a lot of MIM capacitors were proposed. In this paper, in order to realize the variability and controllability of the line characteristics, variable QD-TFMS line is proposed. In order to verify the feasibility of the newly proposed QD-TFMS lines, the transmission lines are simulated for some cases of line parameters(gate width, gate bias, device number, line length etc.).
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  • Mitsuo TAGUCHI, Keiju MATSUO, Kazumasa TANAKA
    Type: Article
    Session ID: BFO2001-6/ROFT2001-6
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    The scattering characteristics of tripole array printed on a thin dielectric film are numerically investigated by using the electromagnetic simulator WIPL-D. The array is composed of tripole elements with arms of equal length. The center of element is put on the vertices of equilateral triangle lattice and the each arm is located on the sides of triangle. The maximum number of elements is 83. The scattered electric fields are numerically examined for the plane wave incidence from the vertical direction to the array. The frequency-selective characteristics of this array are examined.
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  • Mitsuo TAGUCHI, Yoshifumi YANAGISAKO, Junji ARAKI, Kazumasa TANAKA
    Type: Article
    Session ID: BFO2001-7/ROFT2001-7
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    An active loop antenna for the digital terrestrial television receiver is numerically analyzed. This rectangular loop antenna is formed by crank-type undulation of wire. The amplifier circuit with silicon transistor 2SC3587 is integrated between the feed point of loop and the coplanar waveguide feeder. The loop antenna is analyzed by using the electromagnetic simulator WIPL-D and the scattering parameters of amplifier are obtained by using the circuit simulator S-NAP. The actual gain of this antenna with 110 mm by 50 mm in size is more than 8 dBd at the frequencies from 470 MHz to 590 MHz.
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  • Shunsuke Suzuki, Soichiro Yamaguchi, Hideki Inaba, Shigeru Egashira
    Type: Article
    Session ID: BFO2001-8/ROFT2001-8
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    The Ladder antenna is composed with linear elements over conductor plate. First, the ladder antenna with two steps of square loop and rectangular loop which have the loop length of one wave length are analyzed by the moment method, and the calculated results of radiation pattern is reported. Next, multi step ladder antenna composed with multi loops is considered. Moreover, we consider parallel multi step ladder antenna connected with two of multi step ladder antennas and present the calculated results. In results a good radiation pattern is obtained.
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  • naohiro Suenaga, Ichiro Oka, Shigeru Uchino, Shigeru Egashira
    Type: Article
    Session ID: BFO2001-9/ROFT2001-9
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    A rectangular patch antenna with two rectangular patches connected by a transmission line is set on earth plate is considered. The characteristic impedances of this antenna are obtained by transmission line approximate. Characteristic impedance of patches are larger considerably than that of connecting transmission line. Using these characteristic impedances, current distributions of antenna are caluculated, and it is confirmed that the directivities of antenna caluculated from the current distribution agree well with measured values.
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  • Daiki MIZUNAGA, Hideki KOBAYASI, Michiaki NAKAMURA, Masaaki YAMASAKI, ...
    Type: Article
    Session ID: BFO2001-10/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    It is well known that the parallel branch wire loading technique is an effective method to reduce the size of loop antenna. In this paper. we introduce a parallel branch wire loaded rhombic loop antenna to reduce the size of the rhombic loop antenna. As a result, the resonant frequency of the rhombic loop antenna with parallel branch wire loading becomes lower compared to the resonant frequency of loop antenna without loading, and it is realized the reduction of loop size by 30〜40% using the parallel branch wire loading.
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  • Hideki KOBAYASHI, Daiki MIZUNAGA, Mitiaki NAKAMURA, Masaaki YAMASAKI, ...
    Type: Article
    Session ID: BFO2001-11/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Study of Yagi-Uda array antenna using loop elements with the parallel branch wire loading is hardly done. In this paper, we examine a gain characteristic of two element Yagi-Uda array antenna using rhombic loops with the parallel branch wire loading. And we also examine it's the most suitable antenna parameter in order to obtain high FB ratio.
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  • Yuta FUJII, Takehiko TSUKIJI
    Type: Article
    Session ID: BFO2001-12/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    We studied on circularly polarized wave characteristics of a normal mode herical antenna. The normal mode herical antenna consists of a series connection structure of infinitesimal dipole antenna and infinitesimal circular loop antenna. Therefore it's expected to have circularly polarized wave when the magnitude of electric field of dipole and that of circular loop are equal and their phase difference is 90°. In this paper, with moment method, we exerimined the shape of the normal mode herical antenna with good axial ratio. As the results, parameters for the normal mode herical antenna with axial ratio less than 0.15dB in all directions in the vertical plane are as follows; at 1000MHz(wavelength λ=30cm), herical circumference radius r=1cm=λ/30, pitch p=0.6cm=λ/50, number of turn t=2.5turns.
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  • Kei Kataoka, Masaharu Takahashi, Minoru Abe
    Type: Article
    Session ID: BFO2001-13/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    In recent years, the mobile Internet has been increasing. The mobile radio communication tools used indoors are the cellular phones, PHS, IMT-2000, the wireless LAN, Bluetooth, and so on. They are used at sub-micro wave band(1-3GHz). Since the electromagnetic interferences between mobile communication systems have become the problem the necessity for the thin sub-micro wave absorber suited for interior decoration is increasing. In this paper, we focus on the ferrite wave absorber of wedge structure and analyze its reflection characteristics depended on structure by FDTD method. As the result, we can obtain the wedge ferrite wave absorber, which has the reflection coefficient of less than -20 dB at sub-micro wave band.
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  • Kazunori UCHIDA, Chang-Kwon LEE, Masao UEMURA, Souichirou TAJIMA, Tosh ...
    Type: Article
    Session ID: BFO2001-14/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    This paper is concerned with an application of ray tracing method(RTM)to electromagnetic wave propagation in a model house. The main frame of the house is made of steel plates and most of the other parts, such as walls, floors and ceilings, are made of woods. Since we cannot ignore the transmitted waves through walls, floors and ceilings in this type of house, we have to develop a ray searching algorithm taking account of transmitted rays through them. In this paper we propose a simple algorithm which neglects thickness in searching rays, but we consider thickness effect in calculating fields in terms of the reflection and transmission coefficients of a three-layered lossy dielectric slab. Numerical examples are given for the propagation characteristics such as the cumulative distribution of field strength in comparison with the experimental data.
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  • Jiro IWASHIGE, Kenta NAKASHIMA, Tomoya UEDA
    Type: Article
    Session ID: BFO2001-15/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    We analyze the electromagnetic fields of the waves which are transmitted from one side of a building and reach the other side over its rooftop. We consider the influences of the rooftop obstacle on the propagation characteristics, and show that a conductor plate of suitable height erected on the building rooftop can suppress the attenuation of received electric field strength. The analysis employed in this paper is performed by Geometrical Theory of Diffraction(GTD or UTD). And we consider material such as concrete or earth and slope diffraction of the waves grazing along the building rooftop.
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  • Yutaka ISODA, Takeshi FUKUSAKO, Nagahisa MITA
    Type: Article
    Session ID: BFO2001-16/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Recently, wireless communication has gotten attractive developments in a lot of fields. Adaptive array antenna forming a desired beam pattern is an important system in recent wireless communications. This paper is devoted to a novel amplitude control device with compensated phase based on a Q control technique of a microstrip resonator, so that desired nulls directed to undesigned signals can be formed in the beam pattern with fixed directivity of the adaptive array. The structure of this device is made of two microstrip lines coupled by a slot in the ground plane. The authors have been studied on some electrical means to control the amplitude.
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  • Eisuke Nishiyama, Masayoshi Aikawa, Akihide Sakitani, Shigeru Egashira
    Type: Article
    Session ID: BFO2001-17/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    In this paper, the FDTD method is applied to the stacked microstrip antenna. A single patch antenna has a low gain(5-8 dBi)and a narrow bandwidth. By stacking a parasitic element on a microstrip patch antenna, the antenna with high gain or wide bandwidth can be realized. These characteristics of stacked microstrip antenna depend on the distance between a fed element and a parasitic element. The input impedance, the directivity, and the near field distribution are calculated very accurately and the relation between the wideband and the gain enhancement and the calculated near field distributions of the stackd microstorip antennas are discussed.
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  • Eisuke NISIYAMA, Kenji YAMAGUCHI, Masayoshi AIKAWA, Akihide SAKITANI
    Type: Article
    Session ID: BFO2001-18/ROFT2001-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Again of a single microstrip antenna increases by stacking a parasitic element at a distance of 0.5 λ above a fed element. Further a stacked microstrip array antenna has a high gain and high efficiency. In this paper, to make clear how the gain increases, we analyze directivity of two element microstrip array antenna with parasitic elements using FDTD method.
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  • Type: Appendix
    Pages App1-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Type: Cover
    Pages Cover2-
    Published: January 29, 2001
    Released: June 23, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Download PDF (70K)
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