Mitsumi Electric Company Ltd.

Nhk Spring Co., Ltd.

Junji Yamauchi

Hisamatsu Nakano

Michiya Masuda

Ryouichi Tazawa

Yuichi Yamamoto

Akira Miyoshi

Yoichi Asano

Masaaki Miyata

Shigeru Kawaguchi

Kotaro Fujimori

Hidekazu Umetsu

Hiroaki Mimaki

An antenna unit consists of an EBG reflector, a single curl antenna supported at a central portion of the EBG reflector, and a periodic structure upper plate disposed apart from a principal surface of the EBG reflector by a predetermined distance. The EBG reflector includes a substrate having the principal surface and (Nx&#xd7;Ny) square patches which are printed on the principle surface of the substrate and which are arranged in a matrix fashion (lattice structure). The periodic structure upper plate consists of a film and (Nx&#xd7;Ny) square patch-like conductors printed on the film. The (Nx&#xd7;Ny) square patch-like conductors are disposed so as to oppose to the (Nx&#xd7;Ny) square patches, respectively.

Antenna unit having a single antenna element and a periodic structure upper plate

An arrayed-waveguide grating type optical multi-demultiplexer includes input waveguides, a first slab waveguide, a channel waveguide array, a second slab waveguide, and output waveguides. A pair of different refractive index regions, each having a refractive index different from that of the second slab waveguide, are formed on the second slab waveguide near a boundary between the second slab waveguide and channel waveguide array. The different refractive index regions project in peninsular shapes from both side portions of the slab waveguide. Light traveling from each waveguide of the channel waveguide array toward the output waveguides passes through the different refractive index regions. An optical distribution with a flattened field-distribution peak is created at a boundary between the second slab waveguide and output waveguides.

Optical multi-demultiplexer

An optical multi-demultiplexer of the present invention comprises an input waveguide to which wavelength division multiple signals are applied, a plurality of output waveguides for demultiplexing and outputting the wavelength division multiple signals, an arrayed waveguide including a plurality of channel waveguides having different waveguide lengths, an input slab waveguide, and an output slab waveguide. The input slab waveguide is provided between the input waveguide and the arrayed waveguide. The output slab waveguide is provided between the arrayed waveguide and the output waveguides. The input slab waveguide is formed with tapered island regions having a refractive index lower than that of the core layer of the slab waveguide. The island regions are situated in positions opposite the channel waveguides of the arrayed waveguide.

A thin plane antenna that copes with the horizontally polarized waves and the vertically polarized waves, or the levo-rotary polarized waves and the dextro-rotary polarized waves, and in which a loop-shaped plane antenna element ( ) is arranged in parallel with a ground plane ( ), and a first feeder conductor ( ) and a second feeder conductor ( ) having feeding points displayed by 90 degrees are arranged between the plane antenna element and the ground plane. Central conductors ( ) and ( ) of the coaxial lines are connected to the first and second feeder conductors, and external conductors ( ) and ( ) thereof are connected to the ground plane to feed electric power to the antenna element through the electromagnetic coupling. When the electric power is fed from the first feeder conductor ( ), the horizontally polarized waves are radiated and when the electric power is fed from the second feeder conductor ( ), the vertically polarized waves are radiated. Upon changing over the first and second feeder conductors, the horizontally polarized waves and the vertically polarized waves can be transmitted and received. By providing the horizontal antenna element with slide elements, further, the levo-rotary polarized waves and the dextro-rotary polarized waves can be transmitted and received.

Method of feeding flat antenna, and flat antenna

Growing community of inventors

Tokyo, Japan

Junji Yamauchi