Thin-film slot antennas for 700 GHz submillimeter wave radiation were designed on the basis of the experimental results obtained at microwave frequency regions, and fabricated with photolithographic methods. The antenna patterns measured for the HCOOH laser radiation agreed well with the theoretical antenna pattern. This shows that the fabricated antenna works as a slot antenna in the 700 GHz submillimeter region.

Thin-film slot-array receiving antennas fed by coplanar waveguide (CPW) were fabricated on fused quartz substrates, and the antenna properties were investigated at 700 GHz. It was confirmed that the transmission efficiency of CPW was 0.83/λm, and the rate of radiated power from a slot antenna was 0.5 at 700 GHz. The fabricated antennas worked as expected from the theory based on the transmission line model, and the two-dimensional 83 slot-array antenna fed by CPW increased the power gain by 11 dB over a single-slot antenna. The power gain of the antenna was 13 dBi and the aperture efficiency was 40% when the 700 GHz-submillimeter wave was irradiated through the substrate.

Thin-film YBCO Josephson junctions were successfully fabricated by a pulsed excimer laser ablation, and the mixing experiments in the microwave region (820 GHz) were carried out at the temperature of 77 K. The IF output maximum was obtained at the bias voltage midway between the zero and the first Shapiro steps for the fundamental mixing. For the 2nd harmocic mixing, the IF output maximum was obtained at a zero bias voltage, and the conversion efficiency was -14 dB at the microwave frequency of 18 GHz. These results strongly suggest that the fabricated thin-film Josephson junctions work well at the temperature of 77 K as detectors and mixers in the microwave regions (820 GHz).

Thin-film 2-arm Archimedean spiral antenna coupled with a bismuth (Bi) microbolometer was fabricated on a fused quartz substrate backed by cupper (Cu) plate reflector. Antenna patterns of the device agreed with the theoretical patterns derived from the imaging force model at 100 GHz band. The detected voltages of the antenna exhibited a periodic variation with changing the thickness of the substrate. The maximum and minimum detected voltages were obtained when the substrate thickness was odd and even integer multiples of a quarter of the wavelength in the substrate, respectively. Furthermore, the detected voltages were almost constant within the change of 3 dB ranging from 76.9 to 106.8 GHz. The wide band characteristic of the antenna was obtained.

The warm carrier devices which have thin-film antennas were fabricated, and their detection properties were studied at RF, microwave and CO2 laser frequencies. It is found that the static TV characteristic of the fabricated devices persists up to 9.5 GHz microwave frequencies, but does not at CO2 laser frequency.