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.

To realize a highly efficient small antenna, high-Tc superconductors are adopted to fabricate both a self-resonating helical radiator and a quarter-wave matching circuit. The actual gain and bandwidth measured at 478 MHz using a 1/45-wavelength radiator were respectively 1.5 dBi and 0.35%, indicating that this type of antenna has a high radiation efficiency and a fairly wide bandwidth. It is also confirmed through experiments and theoretical simulations that a decrease in the surface resistance of the radiator more effectively improves the radiation efficiency than a decrease in the surface resistance of the matching circuit.

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 describes an innovative, high-speed optical backboard bus composed of an optical star coupler, optical-transmitter modules, optical-receiver modules, and optical multi-mode glass fibers. A highly efficient optical coupling structure with an aspherical lens and a laser diode was designed to achieve a coupling efficiency of 90%, enabling distribution of optical signals at up to 1 Gb/s to 50 function boards. Embedded optical fibers in a printed circuit board were used to achieve precise control of the optical propagation delay times and permit a high packaging density. We developed small laser-diode and photo-diode modules suitable for optical coupling with the embedded fibers. A fabricated prototype optical backboard bus controlled by a controller IC mounted on a function board was able to successfully distribute high-speed optical signals to function boards with a high packaging density.