-
Article type: Cover
Pages
Cover1-
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
-
Article type: Index
Pages
Toc1-
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
-
Masao YAMAMOTO, Hiroyuki FURUTA, Mikio MAEDA, Kimiyuki OYAMADA
Article type: Article
Pages
1-6
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
A phase-diversity technique is a wise option to realize wideband TV program transmission systems with closely-arranged optical signals in broadcasting stations. We compared a optical QPSK modulation using a microwave QPSK modulator with a direct optical QPSK modulation. This report shows by simulation that the former can realize DQPSK coherent detection using the phase diversity easier than the latter.
View full abstract
-
Makoto Funabiki, Shinichi Miyamoto, Norihiko Morinaga
Article type: Article
Pages
7-12
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
Code division multiple access (CDMA) scheme is a current subject of great interest as a multiple access scheme for indoor optical wireless communication system. In this paper, we discuss the performance of line-of-sight indoor optical wireless communication system using PPM/CDMA scheme. At first, we evaluate the downlink and uplink performances and show that, because of multiple access interference, the number of accommodated terminals and the coverage area are much restricted. In order to obtain the large number of accommodated terminals and large coverage area, we propose a new zone construction method which divides the communication channels spatially. Numerical results conclude that the number of accommodated terminals and coverage area can be much improved by using proposed zone construction.
View full abstract
-
Fumio Sakamoto, Yoshio Nikawa, Masaru Chino
Article type: Article
Pages
13-18
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
Radlo absorptive materials and shielding materials in microwave and millimeter wave frequencies can be used to reject the bazardous EM radiation circurnstances. In this study, the materials dispersed graphitized carbon and carbon fiber in silicone rubber are discussed in the frequency range from 40 MHz to 40 GHz. For the single layer radio absorptive materials, it is found that good absorptive characteristics can be obtained as long as narrow frequency band. For the two and three layer, it is found that absorptive bandwidth can be obtained wider than that obtained for single layer radio absorptive materials. Shielding characteristics for the lossy layered materials are also discussed.
View full abstract
-
Atsushi HASE, Yoshinobu OKANO, Koichi ITO
Article type: Article
Pages
19-24
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
The human body significantly alters characteristics of the antenna, which is used for cellular telephones and similar communication devices. This interaction as well as the resultant deposition of microwave power in the human body (specific absorption rate-SAR) are of particular interest for potable radio equipment. In this paper, measurements by the thermographic method using an infrared-camera and tissue equivalent phantom is introduced to estimate the SAR in the human head exposed to microwave sources.
View full abstract
-
Hiroshi NISHIGAKI, Koichi ITO
Article type: Article
Pages
25-30
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
A Printed antenna generating a circularly polarized conical pattern can be effectively employed as a land-mobile antenna for satellite communications. Because of the conical pattern and fairly wide beamwidth in a vertical plane, there is almost no need for tracking the satellite. The authors have presented the design of a printed antenna composed of strips and slots generating circularly polarized conical patterns. However the original design is not suitable for the application of the higher gain. In order to get the higher gain, various types of antennas with an electronically auto-tracking mechanism have been studied recently. Such antennas require phase shifters or switches to form a desired beam. In this paper, we propose a beam-switching printed array antenna composed of strips and slots.
View full abstract
-
Takanori Noro, Shin-ichirou Matsuzawa, Koichi Ito
Article type: Article
Pages
31-36
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
Recently, an active antenna which is composed of printed antennas and a circuit with active element on the same substrate have been investigated. In the analysis of the antenna, we need to treat the circuit by the electro magnetic simulator. In this parer, we show numerical results of the radiation pattern of beam-switching antenna using a FDTD method which can treat a passive and an active elment easily.
View full abstract
-
Satoshi IKEDA, Yoshiaki MORIYA, Eiji SIBUYA
Article type: Article
Pages
37-42
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
At present days, communication systems have been changing from analog systems into digital systems. Broadcasting satellite (BS) will also be changed to digital systems following BS-4,that will be launched in 1999. In general digital systems, it is remarkable that propagation quality will he degraded if the fluctuation of propagation characteristic has gotten over its margin range, compared with analog systems. The carrier to noise ratio (C/N) is used for the video reception quality evaluation. We have been under observation on it for a long term, and have considered about propagation problems.
View full abstract
-
Masumi NAGAHORA, Motoyuki TAKAHASHI, Yoshiaki MORIYA, Hiroto SAKURADA
Article type: Article
Pages
43-48
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
A digital ground broadcasting will be started in the year 2000. The digital broadcasting have the advantage of distinct pictures in comparison with the analog systems on low carrier to noise ratio. The TV broadcasting signals level has varied in sine wave shape, and repeated the fluctuation of the signal level for ten and several seconds by passing airplane. The quasiperiodic level fluctuation exceeding 2dB was sometimes more than 4dB. This phenomenon was derived by the modeled and given calculations. It has understood that the receiving antenna directivity influences the characteristics.
View full abstract
-
Takeshi Oishi, Masami Sekiguchi, Masayuki Ishida, Masakatsu Tanaka, Hi ...
Article type: Article
Pages
49-54
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS
We report the result of experiments on isolation between receiving and transmitting antenna in television relay stations.Through the experiments with 5GHz-band scale model of a television relay station, we conclude that any combination of antenna polarization is not enough to get desired isolation in the case of being reflectors for example like bushes on the way of the beam. Finally, we suggest that the method of coventional television relay system can be adopted for the SFN in little case e.g. gap filler.
View full abstract
-
Article type: Appendix
Pages
App1-
Published: February 12, 1998
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS
FREE ACCESS