Ceramic components used for radio frequency communication equipment

摘要

The mobile phone system in Japan has undergone rapid progress in these four years, with 50 million phone units in use at the present time, and this number is increasing at a rate of 10 million per year. The i-mode mobile phone system which allows mobile phones to exchange e-mails through the Internet, is expanding at an annual rate of 2 million units. Although 800MHz was used in the beginning for this system, a frequency band of 1.5GHz is currently in use (Fig. 1 and 2). For the year 2001, a broadband communication system at ITM 2000 specification is expected to be put into operation. On the other hand, the electronic toll collection system (ETCS) within the intelligent transport system (ITS) is scheduled to be operational soon(Fig. 4). This ETCS uses the 5.8 GHz band. In the ITS currently in operation, the vehicle information communication system (VICS) is available and is based on the radio frequency. In addition, the future systems soon to be operational include road-vehicle communication and intra-vehicle communication. In the communication systems, dedicated short-range communication (DSRC) is expected to be used. In road-vehicle communication, the microwave at 5.8GHz and light beacons are being considered. For radar operations in this communication system, the use of a millimeter wave of either 60GHz or 76GHz is being considered, and for inter-vehicle communication, infrared light or IMS (industrial, scientific, and medical) band is also used.