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Displaying 1-15 of 15 articles from this issue
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Article type: Cover
Pages Cover1-
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (13K) -
Article type: Index
Pages Toc1-
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (61K) -
Hiroaki NAKABAYASHI, Shigeru KOZONOArticle type: Article
Session ID: ROFT2000-70
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSComputer simulations on frequency correlation coefficient for instantaneous wide-band received signal-level in mobile communications were carried out. As a result, it showed that the correlation coefficient depends on a received bandwidth and a slope of arriving wave amplitude in delay profile. Furthermore, the simulation results were compared with theoretical correlation value when the amplitude had uniform distribution, it cleared the dependence on the amplitude distribution of delay profile.View full abstractDownload PDF (518K) -
Masaru SUGA, Masahiko SHIGA, Seiji ISOBEArticle type: Article
Session ID: ROFT2000-71
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSISDB-T which used OFDM modulation was adopted for Digital Terrestrial Television Broadcasting system in Japan, because it has advantage against multipass. The re-transmitting signal is degraded by the coupling-multipass interference from transmitting antenna to receiving antenna. We have been developing the loop canceller to cancel the coupling-multipass interference. This paper describes outline of field trial results at the Otaru relay station. In the trial, we propose that the coupling-multipass interference is estimated by the delay profile of coupling-multipass.View full abstractDownload PDF (759K) -
Kuniaki OTSUKA, Katsumi IZAWA, Seiji ISOBEArticle type: Article
Session ID: ROFT2000-72
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDigital Terrestrial Television Broadcasting(DTTB)system of Japan was adopted in 1999, which uses Orthogonal Frequency Division Multiplexing(OFDM)as the modulation scheme. One of the most influences on the transmission characteristics using OFDM is Inter-Modulation(IM)generating at Power Amplifier(PA)in the transmitter. We have developed the adaptive non-linear corrector, which realizes that the transmitter has both high efficiency and high performance. Also, we have done the test using it at some of the DTTB research and development laboratories of Telecommunication Advancement Organization of Japan(TAO)and got the good results.View full abstractDownload PDF (528K) -
Hiroshi Hatanaka, Kazuhiro Kurosaki, Yu Takami, Masayoshi Nakano, Ryuj ...Article type: Article
Session ID: ROFT2000-73
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSNow in Japan, the Digital Terrestrial Television Broadcasting system is undergoing tests. We made the output filters and designed the channel combiners for the system, and the output filters are being used now. They were made up of dielectric resonators or cylindrical waveguide resonators. It was found that the appropriate order of those BPFs for the output filters and for the channel combiners is 4 or 6. It was also found that the BPFs made up of dielectric resonators have better electronic characteristics and smaller size than those made up of cylindrical waveguide resonators.View full abstractDownload PDF (720K) -
Koichi Ogawa, Hiroshi Iwai, Yoshio KoyanagiArticle type: Article
Session ID: ROFT2000-74
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis paper presents a simple estimation method for the effective performance in a multiple radio wave environment of a handset diversity antenna close to the human body. The proposed method utilizes the complex radiation patterns over the whole solid angle measured in a radio anechoic chamber. The measurement is made by a human phantom comprising a head, a hand and a shoulder simulating a practical talk situation. The phantom is attached to an apparatus which enables radiation pattern measurement in an arbitrarily azimuth cut plane. As a first step of the measurement, correlation and effective gain characteristics of the diversity branches are evaluated by the measured complex radiation patterns, and then the diversity antenna gain(DAG)is calculated by those characteristics. As an example of the proposed method, the relationship between the antenna structure and the DAG is evaluated and the effectiveness of the method is shown.View full abstractDownload PDF (966K) -
Yoshinobu OKANO, Hitoshi TAKAHASHIArticle type: Article
Session ID: ROFT2000-75
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis paper proposes the loop antenna for the system of blind area service in current cellular phone system. In general, one wave-length loop antenna is a mismatch to the coaxial cable. Then, a ring parasitic loop antenna is developed. The parasitic ring is effective though matches the loop antenna to the coaxial cable. In addition, the triple-band antenna that arranged ring parasitic loop antennas in the concentric circular is developed and its characteristics of return loss and radiation patterns are indicated.View full abstractDownload PDF (897K) -
Kyouichi IIGUSA, Takashi OHIRA, Masato TANAKAArticle type: Article
Session ID: ROFT2000-76
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSBy forming slits in a meandering shape with the period of a wavelength in the waveguide on an oversized coaxial waveguide in which TEM mode wave propagates, a horizontal polarized omnidirectional antenna was obtained. A meander slit can be regarded as a series connection of square brackets, although experimental results have shown that the cross polarization discrimination of an antenna composed of meander slits was lower than that of an antenna composed of square brackets. Phase distribution is determined by the center positions of the vertical slit segments. Accordingly, when shaping a beam in thevertical plane, amplitude distribution cannot be controlled by the length of the vertical slit segments, but can be controlled by their width.View full abstractDownload PDF (618K) -
Sumie HOSAKA, Kazuyuki SAITO, Takeshi TANIGUCHI, Hiroyuki YOSHIMURA, K ...Article type: Article
Session ID: ROFT2000-77
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe microwave coagulation therapy(MCT)has been used for the treatment of hepatocellular carcinoma. The microwave energy from the thin coaxial antenna heats the tumor up to the coagulating temperature of the tissue. In the MCT, there is a problem to be improved for the conventional MCT antennas. It is that length of the coagulated region becomes long in the antenna-insertion direction. We have introduced the coaxial-dipole antenna for generating a localized heating around the tip of the antenna. In this paper, we calculated the reflection coefficients and the heating characteristics of the coaxial-dipole antennas by the FDTD method. Moreover, the improvement of the shape of the coagulated region was presented by introducing the indices for evaluating the heating patterns.View full abstractDownload PDF (764K) -
Masaki TANAKA, Hiroyuki YOSHIMURA, Koichi ITOArticle type: Article
Session ID: ROFT2000-78
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this paper, we have focused on the phased array with a photonic feed system. The photonic feed system controls the distributions of antenna excitation by using an optical Fourier transform and an optical/electrical conversion. In the photonic feed system consisted of one laser and a frequency shifter, optical fibers and a frequency shifter have error factors. Therefore we have considered the effects of the error factors on the radiation pattern. At first, we mention a process to statistically calculate the average power patterns including the error factors, and show the calculated examples. Next, we calculate the directive gains, and consider the effects of the error factors on directivity.View full abstractDownload PDF (614K) -
Junwei Lu, Takshi OhiraArticle type: Article
Session ID: ROFT2000-79
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe circular array antenna can offer the controlled beam direction, beam pattern and multiple beams spaced through 360 degrees. Several beams pointing in different directions simultaneously can be electronically controlled at the terminal of elements or multiple ports by using reactively terminated parasitic elements or switched to parasitic and active elements. Comparing with currently used omnidirectional antenna at mobile terminals the physical size of array antenna is too large. As the operating frequency is approximately 2.4GHz, a band suitable for wireless communications and mobile computing, 1/2 wavelength is only 6cm long, it is possible to integrate a small array antenna to the mobile terminals directly. This paper presents the possibility of the physical size reduction of electronically beam steerable antenna arrays by using dielectric embedding techniques. The dielectric embedded antenna arrays, such as switched and multiple-beam(ESMB)antenna array and electronically steerable passive array radiator(ESPAR)antenna array demonstrate that over 50% size reduction and over 80% volume reduction can be achieved by using a high dielectric constant embedding material. The comparisons of the experimental and FD-TD based computer simulation results for dielectric embedded ESMB antenna array are made in this paper. The optimal design considerations and the relationship between electrical characteristics and the parameters of antenna structure for both antenna arrays are also described in this paper.View full abstractDownload PDF (1047K) -
Hideki YAMAMOTO, Tomohiro SEKI, Toshikazu HORIArticle type: Article
Session ID: ROFT2000-80
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSActive array antennas are very interesting for use in the quasi-millimeter wave band or more but conventional units are too complicated and performance is limited. We reduce the number of amplifiers and improve the performance by stacking separate Tx and Rx feeding circuits over a common ground layer that holds all Tx and Rx amplifiers. The Tx feeding circuit allows a multistage amplifier configuration to be established that reduces the number of Tx amplifiers by 50% or more. Separating the Tx and Rx feeding circuits allows both to be optimized so as to reduce the sidelobe levels. We also clarify the effect on antenna performance of mounting all amplifiers on the same ground layer and propose a method to suppress the effect of mounting error. We simulate an 8×8 array and clear a sidelobe level reduction.View full abstractDownload PDF (812K) -
Article type: Appendix
Pages App1-
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (83K) -
Article type: Cover
Pages Cover2-
Published: November 16, 2000
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (62K)
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