A spiral array radial line slot antenna (SA-RLSA) is designed in 22 GHz band. A SA-RLSA excited with a coaxial feeder suffers from aperture illumination fluctuation in amplitude and phase in the circumferential (φ-) direction while in the radial direction, reasonably uniform distribution is observed. Rotational symmetry of radiation patterns is degraded and especially the sidelobe levels are unbalanced. This fluctuation is associated with the generation of the higher order modes in the φ-direction and is the unique defect of SA-RLSA which uses oversized waveguide. In this paper, a novel feeding structure with two pairs of parasitic pins around a coaxial feeder is proposed and designed so as to compensate the rotational asymmetry of aperture illumination. A measurement using the model antenna designed in 22 GHz band demonstrates the enhancement of the rotational symmetry; the circumferential fluctuation is reduced from 5.1 dB and 33 degrees to 1.8 dB and 12 degrees, while the fluctuation in the first sidelobe level suppressed from 10.7 dB to 1.2 dB.

Two-dimensional resonant optical scanners actuated by vertical electrostatic combs with a unique electrical isolation structure have been developed. The isolation on the movable frame surrounding 1 mm-diameter gimbal mirror is made by trenching the top silicon layer of an SOI wafer with leaving the thick bottom layers. Thanks to the large mass of the frame, the resonant frequencies range in 65.0-89.2 Hz for the frame and in 11.9-36.8 kHz for the mirror in a 4 mm4 mm chip. The resultant frequency ratio of the fast/slow axes reaches over 500 and such a high frequency ratio is utilized to display QVGA image by raster scanning of a laser beam.

A lightweight and high gain planar antenna for space use is realized with radial waveguide slotted array and honeycomb structure with the weight of 1.16 kg and the diameter of 920.5 mm. The slot coupling is analyzed by method of moments considering the hybrid mode in the multi-layer waveguide structure. The propagation constant of the honeycomb structure is measured and the low-loss property is obtained at the frequency range of 8 GHz. The fabricated RLSA is measured and the reflection is around -10 dB in 8 GHz band. The measured aperture fields agree with the calculation in the radial direction. In the azimuthal direction, on the other hand, the fields show ripples of 6 dB and 60 degree. The gain of 35.9 dBi with the efficiency of 58.7% is obtained at 8.6 GHz.