A wireless tag system has been designed and developed for maintaining and managing outdoor communication facilities. This system employs an infrared (IR) beam and an electromagnetic wave with a radio frequency (RF), and is constructed using IR-RF tags, an IR commander, and an RF receiver. The IR command radiation with strong directivity enables a maintenance operator to recognize a target facility, and the RF response without directivity enables a management system to obtain data from within a large circular area. Solar and secondary batteries are also adopted as the power module in the tag to allow easy maintenance at long intervals. IR signal communication is possible up to a distance of 9 m, and RF signal communication is possible within a circle with a radius of 9 m.

This paper describes the properties of non-dispersive and dispersive delay lines fabricated using EuBaCuO superconducting films. The 24 cm long stripline non-dispersive delay line showed a very low loss of 0.3 dB/nsec at 77 K and 10 GHz, and no dispersion at a delay time of 2.3 nsec at frequencies below 20 GHz. The 14 cm long microstrip dispersive delay line with modal dispersion exhibited a relative delay time of approximately 120 psec in the 118 GHz frequency range. The 26 cm long stripline dispersive delay line with structural dispersion due to coupling provided a relative delay time of 230 psec in the above frequency range and roughly the same loss as a non-dispersive delay line.

A new multi-functional card with a display, sounder and input keys, and related communication equipment, including a microwave base station and a contactless surface reader/writer, have been developed to perform the functions of positioning, paging, returning a message and identity certification. We confirmed that a prototype subsystem was capable of providing a simple and automatic call forwarding service. The multi-functional card as an ID card and a personal data terminal, and its subsystem can provide new personal services for a multimedia office.

This paper describes the structure and properties of superconductive small antennas with thin-film matching circuits. These circuits make it possible to realize small antennas, 38 mm20 mm16 mm in size. This is one quarter the length of our previously reported ceramic antennas. The actual gain of this antennas was -4.5 dBi at 470 MHz. This value is 5.5 dB higher than that of Cu antennas with exactly the same structure.

This paper reports on the properties of thin-film thermal switches that are monolithically fabricated on high-Tc superconductive filter. Operating at a wide temperature range of 50-77 K, it was found that the switch could control the center frequency by -10 MHz with an increased insertion loss of less than 0.7 dB. In an on-off switching operation of filter characteristics using thin-film switches, power consumption was approximately 20 mW at 77 K, and the signal decay time as a switching speed was 30 ms at 76 K with a switch current of 70 mA. The decay time decreased exponentially as the switch current or the temperature setting increased.

This paper describes a new method for joining BiSrCaCuO superconductors (BSCCO) which realizes low microwave loss and high mechanical strength. This method consists of two processes. In the first the BSCCO surface is metallized with Ag and in the second a joint is formed by using thermally curable Ag paste. With this method, we obtained a joint with a loss of 0.3 dB around 1.1 GHz with the co-axial cavity techniques. Furthermore, the mechanical strength of the joint was greater than that of the BSCCO sample. From the results of DC resistance measurements and SEM observations, we attribute this good performance to the adhesion and continuity of the metallized Ag with the BSCCO surface.