摘要:
PROBLEM TO BE SOLVED: To provide an antenna device in which degradation of antenna characteristics, e.g., expansion of beam width or decrease in front back ratio, can be minimized while reducing the weight of a reflective plate of meta-material structure.SOLUTION: Since the dielectrics 121, 131 of meta-material reflective plates 120, 130 have cavities 123, 133 formed in the longitudinal direction, the volume is 75% or more and less than 100% when compared with the volume of solid reflective plates. Since the cavities 123, 133 penetrate the dielectrics 121, 131, weight of the meta-material reflective plates 120, 130 can be reduced. But since the volume of the meta-material reflective plates 120, 130 is 75% or more that of solid reflective plates, expansion of beam width of an antenna device 100 can be prevented. Furthermore, since the cavities 123, 133 are formed on the outside of the central parts 122, 132 of a cross-section orthogonal to the longitudinal direction of the dielectrics 121, 131, decrease in front back ratio of the meta-material reflective plates 120, 130 can be prevented.
摘要:
PROBLEM TO BE SOLVED: To provide an antenna configured to reduce a deviation of a half-value angle of directional characteristics in a magnetic phase boundary than conventional ones.SOLUTION: An antenna includes a reflector plate and a radiation element spaced a predetermined distance away from the reflector plate. The reflector plate has slits respectively disposed at end portions of both ends thereof in a direction parallel to an electric field of radio waves radiated from the radiation element. The radiation element is one having an array structure having a plurality of pairs of dipole antenna elements disposed in a direction orthogonal to a magnetic phase boundary of the radio waves radiated from the radiation element.
摘要:
PROBLEM TO BE SOLVED: To provide a radio transmitter-receiver which is free from a shift of a resonant frequency and the reduction in communication sensitivity even with non-contact information recording media interposed between or placed on metal surfaces and is available even in the case of overlap or proximity between non-contact information recording media, a non-contact information recording medium, an information reader/writer, and a management system. SOLUTION: The radio transmitter-receiver includes: a coil 2 incorporating a magnetic material plate 6; and two metal plates 11a and 11b which are disposed in parallel with a direction of a magnetic flux of the coil 2 and in opposition to each other on both sides of the coil 2. COPYRIGHT: (C)2009,JPO&INPIT
摘要:
PROBLEM TO BE SOLVED: To easily acquire characteristic in which antenna gain, return loss, and side lobe ratio are optimum, in condition where the area of an opening part of a main reflector has been determined.SOLUTION: The antenna includes a main reflector 13 which radiates the microwave fed from a waveguide 11 and a slot 12, and a printed circuit board 15 arranged at an opening part of the main reflector 13. A sub-reflection pattern in which small hexagonal metal bodies 16 are arranged in honeycomb is formed on the board 15. In the sub-reflection pattern, two rows of small metal bodies 16 at a central part in magnetic field direction are arranged with a first gap Ga, and small metal bodies 16 on the outside of central part are arranged with a second gap Gb which is smaller than the first gap Ga. The antenna resonance frequency is adjusted by the gap Ga, and a return loss is optimally set by the gap Gb. The small metal bodies 16 on the edge of the opening part in the magnetic field direction of the main reflector 13 are arranged away from the opening part edge by a third gap Gc which is larger than the second gap Gb. A side lobe ratio is set by the gap Gc.
摘要:
PROBLEM TO BE SOLVED: To obtain an antenna device which can maximize an impedance ratio bandwidth in a microstrip patch antenna constitution wherein two parasitic elements are disposed above a feed element. SOLUTION: The device has a patch conductor 1 which is disposed via a dielectric 5 to a grounding conductor 4, a patch conductor 2 which is disposed via a dielectric 6 on the other side of the patch conductor 4 to the patch conductor 1, a patch conductor 3 which is disposed via a dielectric 7 on the other side of the patch conductor 1 to the patch conductor 2 and a feed line which supplies high frequency power between the grounding conductor 4 and the patch conductor 1. A size W2 of the patch conductor 2, the W3 of the patch conductor 3, an electrical equivalent size W3e of the patch conductor 3, a distance t3 between the patch conductors 2, 3 and the relative permittivity εr3 of the dielectric 7 are selected to satisfy W3≤W2≤W3e(t3, εr3). COPYRIGHT: (C)2009,JPO&INPIT
摘要:
PROBLEM TO BE SOLVED: To provide a radio tag reader/writer antenna for efficiently shielding electromagnetic waves harmful to communication with a radio tag. SOLUTION: The radio tag reader/writer antenna includes: an antenna armor for housing a reader/writer antenna which is an antenna for transmitting and receiving the electromagnetic waves to/from the radio tag; and a plurality of electromagnetic wave shielding plates installed to the antenna armor so as to clamp the antenna armor and extended to a radiating direction of the electromagnetic waves from the reader/writer antenna. The electromagnetic wave shielding plates can be installed detachably or slidably. By the electromagnetic wave shielding plates, the electromagnetic waves harmful to the communication with the radio tag are efficiently shielded. COPYRIGHT: (C)2009,JPO&INPIT
摘要:
PROBLEM TO BE SOLVED: To solve the problem that a radar-use antenna device, in which a primary radiator using a coaxial line is fixed to a feed line and a reflection mirror is rotated at the outer circumference of the primary radiator, becomes expensive because the number of components is increased when being made high in gain and that the high output of a radar device is limited because transmission loss is increased in a high frequency by using the coaxial line and power-proof characteristics are more degraded than that in a waveguide path. SOLUTION: A waveguide is used for a feeding path, and an electromagnetic horn is used for a radiating part as a fixed primary radiator 12. A conical reflector is installed at an upper part of the electromagnetic horn, and an antenna forms a horizontally non-directional beams when the conical reflector reflects a beam by the electromagnetic horn. Reflectors (main and sub reflectors) 11a and 11b are rotated at the outer circumference of the primary radiator. COPYRIGHT: (C)2008,JPO&INPIT