A parallel branch wire element which is attached parallel to the antenna element works as a loading element consist of a short-circuited coaxial stub. In this paper, the characteristics of dual-frequency triangular loop antenna with the parallel branch wire was analyzed. The input impedance and the resonance frequency were obtained by using the moment method for the analysis. As a result, the operation and the effect of the parallel branch wire were clarified. Pracical design parameters to optimize the antenna size and the dual frequency property of the triangular loop antenna with the parallel branch wire are presented.
The interaction between human body and antenna with spread of cellular is a serious problem. For clearly the problem, we set up the calculation model using lossy dielectric sphere which looks upon as human head and introduce the exact solution using special functions in 3-dimensions for the model. We show the radiation pattern and SAR (Specific Absorption Rate) when a half wavelength dipole antenna is put near the sphere that is layer structure consists of brain and skull. We can conform the calculation method to be effect by measurement.
In recent years, the office, home and so on are equipped with various electric and electronic devices. The electromagnetic waves that are radiated from these devices are reflected by the wall of room or penetrate the wall from outside, then they interfere to the other device. It's necessary to decrease the reflection and transmission by the concrete wall. In this paper, we analyzed the reflection and transmission characteristics of dome shape surface wall by the FD-TD method. Its surface has asperity form that newly proposed. As a result, we obtained that the dome shape surface wall consumed a power of electromagnetic wave in the wall more than a plain wall. Then the dome shape surface wall can oppress reflection and transmission.
Temperature distribution in a human body phantom exposed by an electromagnetic field has been analyzed by using the finite difference time domain method combined with the heat transfer equation (FDTD-HTE). However, the calculated temperature distribution near the air/phantom interface has large error compared with an experiment. We propose a novel surface boundary condition (SBC) for analyzing the electromagnetic heating in a human-equivalent phantom. The validity of the proposed SBC is tested numerically
In muti-channel CATV transmission systems, non-linearity of amplifiers causes intermodulation(IM). IM distortions impair the signal in CATV transmission and degrade the BER in digital channels. We have measured probability density function(p.d.f.) of IM in various conditions, and studied on relation between p.d.f. and BER of 64QAM.
Marathon live broadcastings are one of the most popular sports programs in Japan and expected as promising programs for the satellite digital broadcasting which will start from the end of this year. Although the cost of a marathon live production had been very high so far because mobile links were generally required, it becomes no longer expensive by 800MHz COFDM (Coded Orthogonal Frequency Division Multiplexing) FPUs (Field Pick-up Units) which we introduced for the last year's Tokyo International Marathon live and enabled the production cost to be reduced significantly. The planning of COFDM mobile links are more difficult than traditional analog ones, because they are mainly used for out of sight transmissions which propagation are complicated. In such a circumstance, It is required to analyze not only reception power but also delay spread, which generally depend on the surroundings such as buildings, trees etc. This paper describes the results of multi-path propagation measurements in mobile links with 800MHz COFDM FPUs as the "Tokyo Marathon" held in a metropolitan area and at the "Izumo Ekiden" held in a rural area.
NHK Oita broadcasting station is in the cultural facilities complex "OASIS HIROBA 21" built in September 1998. The facilities has been built in cooperation with Oita prefectural government and private enterprise. "CANVAS" - the multipurpose studio in NHK, is designed to make systematically and functionally use of the theater for producing a TV-program. As a concrete example of practicing to open a broadcasting station to a local community, we report the function and actual results of use of CANVAS and consider how a broadcasting station should cooperate with local cultural facilities and what we should do as a local broadcasting station in the future.
We developed a traffic information display system for broadcasting. This system is composed of a server computer which is directly connected to Japan Road Traffic Information Center(JARTIC) using a lease line and a picture draw system. A server computer receive various traffic information(traffic congestion, traffic restriction, traffic accident, etc.)about Kanto area expressway from JARTIC and transmit these information to a picture draw system. A picture draw system generate and display various still image expressing these information. We have been able to broadcast traffic information anytime using this system.
Recently, weather information in the news program is refered to importance. Especially, information on the weather satellite 'Himawari' is important. But the data that can be obtained by 'Himawari' has some kinds of information, but it is not enough to us. A satellite 'TRMM' shows more weather information to us, however, visualization of 'TRMM' data is not so easy. Here, we describe and outline of visualizing 'TRMM' data.