Abstract: A slot antenna apparatus includes a grounding conductor having an outer edge including a first portion facing a radiation direction and a second portion other than the first portion, a one-end-open feed slot formed in the grounding conductor along the radiation direction such that an open end is provided at a center of the first portion, and a feed line including a strip conductor close to the grounding conductor and intersecting with the feed slot at at least a part thereof to feed a radio frequency signal to the feed slot. The slot antenna apparatus further comprises at least one one-end-open parasitic slot having an electrical length equivalent to one-quarter effective wavelength in a certain stop band, the parasitic slot having an open end at the second portion, and being formed in the grounding conductor so as not to intersect with the feed line.

Abstract: A photonic crystal device according to the present invention includes: a first dielectric substrate 104 having a first lattice structure, of which the dielectric constant changes periodically within a first plane; a second dielectric substrate 105 having a second lattice structure, of which the dielectric constant changes periodically within a second plane; and an adjustment device (pivot 303) for changing a photonic band structure, defined by the first and second lattice structures, by varying relative arrangement of the first and second lattice structures. The first and second dielectric substrates 104 and 105 are stacked one upon the other.

Abstract: A variable slot antenna includes: ground conductors 101a and 101b, which are divided by a slot region 109 both of whose both ends are open ends 111a and 111b; a feed line 115 for feeding power to the slot region 109; a first selective conduction path 119 connecting between the ground conductors 101a and 101b in a direction of the open end 111a as viewed from a feeding site 113; and a second selective conduction path 121 connecting between the ground conductors 101a and 101b in a direction of the open end 111b as viewed from the feeding site 113. In a first driving state, the first selective conduction path 119 is allowed to conduct and the second selective conduction path 121 is left open, so that a main beam is emitted in a direction 123a of the second selective conduction path 121 as viewed from the feeding site 113. In another driving state, the selective conduction paths are controlled differently so that the main beam direction is switched to a direction 123b.

Abstract: A variable-directivity antenna according to the present invention includes at least three linear passive elements, which are arranged parallel to a Z-axis so as to surround a feed element. Each of those passive elements includes at least two element pieces, etc. that are arranged parallel to the Z-axis and switching elements, etc. of a first type. The passive element assembly further includes at least one switching element, etc. of a second type that makes two adjacent passive elements electrically continuous with each other when turned ON but electrically insulates them from each other when turned OFF. By turning ON and OFF the at least one switching element of the first type and the at least one switching element of the second type, the antenna can change its directivities.

Abstract: A differential transmission line includes: a substrate; a ground conductor layer; and a first and a second signal conductor disposed in parallel to each other on the substrate. The first signal conductor and the ground conductor layer compose a first transmission line, whereas the second signal conductor and the ground conductor layer compose a second transmission line. The first transmission line and the second transmission line compose a differential transmission line. The differential transmission line includes a curved region, with a straight region being connected to each end of the curved region. In the ground conductor layer in the curved region, a plurality of slots orthogonal to a local transmission direction of signals in the curved region are formed, and the slots are connected to one another on the inner side of the curvature.

Abstract: In a transmission line pair including a first transmission line and a second transmission line which is so placed in adjacency that a coupled line region to be coupled with the first transmission line is formed, in the coupled line region, the first transmission line includes a first signal conductor which is placed on one surface which is either a top face of a substrate formed from a dielectric or semiconductor or an inner-layer surface parallel to the top face and which has a linear shape along its transmission direction, and the second transmission line includes a second signal conductor which is placed on the one surface of the substrate and which partly includes a transmission-direction reversal region for transmitting a signal along a direction having an angle of more than 90 degrees with respect to the transmission direction within the plane of the placement, and which has a line length different from that of the first signal conductor.

Abstract: A transmission line apparatus includes: a substrate 101 with a ground conductor plane; and first and second signal strips 102a, 102b supported on the substrate 101 in parallel with each other. The apparatus further includes at least one additional capacitance element 301 that connects the first and second signal strips 102a, 102b together. The element 301 includes: a first additional conductor 303 spaced from the first signal strip 102a; a second additional conductor 305 spaced from the second signal strip 102b; and a third additional conductor 307 connected to the first and second additional conductors 303, 305 at respective points. When measured in a signal transmission direction, the smallest width W3a of the third additional conductor 307 is shorter than the length L1 or L2 of the first or second additional conductor 303 or 305. And the additional capacitance element 301 has a resonant frequency that is higher than the frequency of a signal being transmitted.

Abstract: A polarization switching/variable directivity antenna according to the present invention includes a radiation conductor plate 12 on a front face, and a ground conductor plate 14 on a rear face, of a dielectric substrate 11. At least one directivity switching element and at least two polarization switching elements are provided within the ground conductor plate 14 on the rear face. The directivity switching element includes a first slot which is formed by a removing a loop-like portion from the ground conductor plate 14 and at least two directivity switching switches (22a to 22d). Each polarization switching element includes a first slot which is formed by removing a loop-like portion from the ground conductor plate 14 and at least one polarization switching switch (23a to 23d).

Abstract: A differential transmission line includes: a substrate; a ground conductor layer; and a first and a second signal conductor disposed in parallel to each other on the substrate. The first signal conductor and the ground conductor layer compose a first transmission line, whereas the second signal conductor and the ground conductor layer compose a second transmission line. The first transmission line and the second transmission line compose a differential transmission line. The differential transmission line includes a curved region, with a straight region being connected to each end of the curved region. In the ground conductor layer in the curved region, a plurality of slots orthogonal to a local transmission direction of signals in the curved region are formed, and the slots are connected to one another on the inner side of the curvature.

Abstract: One transmission line includes a first signal conductor which is placed on one surface of a substrate formed from a dielectric or semiconductor and which is formed so as to be curved toward a first rotational direction within the surface, and a second signal conductor which is formed so as to be curved toward a second rotational direction opposite to the first rotational direction and which is placed in the surface so as to be electrically connected in series to the first signal conductor, wherein a transmission-direction reversal portion in which a signal is transmitted along a direction reversed with respect to a signal transmission direction of the transmission line as a whole is formed so as to include at least part of the first signal conductor and part of the second signal conductor. Such a transmission line is capable of obtaining a suppression effect of unwanted radiation intensity.

Abstract: A polarization switching/variable directivity antenna according to the present invention includes a radiation conductor plate 12 on a front face, and a ground conductor plate 14 on a rear face, of a dielectric substrate 11. At least one directivity switching element and at least two polarization switching elements are provided within the ground conductor plate 14 on the rear face. The directivity switching element includes a first slot which is formed by a removing a loop-like portion from the ground conductor plate 14 and at least two directivity switching switches (22a to 22d). Each polarization switching element includes a first slot which is formed by removing a loop-like portion from the ground conductor plate 14 and at least one polarization switching switch (23a to 23d).

Abstract: A differential transmission line includes: a substrate; a ground conductor layer; and a first and a second signal conductor disposed in parallel to each other on the substrate. The first signal conductor and the ground conductor layer compose a first transmission line, whereas the second signal conductor and the ground conductor layer compose a second transmission line. The first transmission line and the second transmission line compose a differential transmission line. The differential transmission line includes a curved region, with a straight region being connected to each end of the curved region. In the ground conductor layer in the curved region, a plurality of slots orthogonal to a local transmission direction of signals in the curved region are formed, and the slots are connected to one another on the inner side of the curvature.

Abstract: A photonic crystal device according to the present invention includes: a first dielectric substrate 104 having a first lattice structure, of which the dielectric constant changes periodically within a first plane; a second dielectric substrate 105 having a second lattice structure, of which the dielectric constant changes periodically within a second plane; and an adjustment device (pivot 303) for changing a photonic band structure, defined by the first and second lattice structures, by varying relative arrangement of the first and second lattice structures. The first and second dielectric substrates 104 and 105 are stacked one upon the other.

Abstract: An antenna according to the present invention includes a dielectric layer 102 with an upper surface and a lower surface, a signal line strip 101 provided on the upper surface of the dielectric layer 102, and a grounding conductor portion 104 provided on the lower surface of the dielectric layer 102. The surface of the grounding conductor portion 104 includes a plurality of planar areas, each of which has a size that is shorter than the wavelength of an electromagnetic wave to transmit or receive. A distance from a virtual reference plane to each planar area is adjusted on an area-by-area basis. Thus, an antenna, which can change various antenna parameters such as radiation directivity, gain and efficiency dynamically and adaptively according to incessantly changing propagation environment of radio wave, is provided.

Abstract: Inside a multilayer dielectric substrate, there are a spiral-shaped first slot set in a part of a first ground conductor layer and a spiral-shaped second slot in a part of a second ground conductor layer put on the front surface of the multilayer dielectric substrate, the first slot and the second slot are opposite in a spiral winding direction and the first slot and the second slot overlap with each other as viewed from the top face, so that a resonance phenomenon can be produced at a frequency lower than a resonance frequency of a resonator with a conventional structure.

Abstract: In a radio-frequency device in which a dielectric layer, a first conductive layer and a second conductive layer are stacked one on another, the second conductive layer is including a plurality of conductive elements which are arrayed periodically and independently of one another at a specified array pitch, and a plurality of connecting elements for electrically connecting a plurality of mutually neighboring ones of the conductive elements to each other. The connection by the connecting elements is selectively made, thus making it possible to control radiation directivity of an electromagnetic field formed by the first and second conductive layers.

Abstract: A differential transmission line according to the present invention includes: a substrate 101; a ground conductor layer 105 formed on a rear side of the substrate 101; and a first signal conductor 102a and a second signal conductor 102b disposed in parallel to each other on a front side of the substrate 101. The first signal conductor 102a and the ground conductor layer 105 compose a first transmission line, whereas the second signal conductor 102b and the ground conductor layer 105 compose a second transmission line. The first transmission line and the second transmission line compose a differential transmission line 102c. The differential transmission line 102c includes a curved region 104a, with a straight region 104b being connected to each end of the curved region 104a.

Abstract: A differential transmission line according to the present invention includes: a substrate 101; a ground conductor layer 105 formed on a rear side of the substrate 101; and a first signal conductor 102a and a second signal conductor 102b disposed in parallel to each other on a front side of the substrate 101. The first signal conductor 102a and the ground conductor layer 105 compose a first transmission line, whereas the second signal conductor 102b and the ground conductor layer 105 compose a second transmission line. The first transmission line and the second transmission line compose a differential transmission line 102c. The differential transmission line 102c includes a curved region 104a, with a straight region 104b being connected to each end of the curved region 104a.

Abstract: A transmission line apparatus includes: a substrate 101 with a ground conductor plane; and first and second signal strips 102a, 102b supported on the substrate 101 in parallel with each other. The apparatus further includes at least one additional capacitance element 301 that connects the first and second signal strips 102a, 102b together. The element 301 includes: a first additional conductor 303 spaced from the first signal strip 102a; a second additional conductor 305 spaced from the second signal strip 102b; and a third additional conductor 307 connected to the first and second additional conductors 303, 305 at respective points. When measured in a signal transmission direction, the smallest width W3a of the third additional conductor 307 is shorter than the length L1 or L2 of the first or second additional conductor 303 or 305. And the additional capacitance element 301 has a resonant frequency that is higher than the frequency of a signal being transmitted.

Abstract: An RF circuit component according to the present invention includes a waveguide 1 and at least one resonator 2, which is arranged inside the waveguide 1. The resonator 2 includes at least one patterned conductor layer, which is parallel to a plane that crosses an H plane, and resonates at a lower frequency than a cutoff frequency, which is defined by the internal dielectric constant, shape and size of the waveguide 1, thereby letting an electromagnetic wave, having a lower frequency than the cutoff frequency, pass through the inside of the waveguide 1.