Abstract: There is provided a metal plate antenna transmitting and receiving wireless signals conforming to a prescribed communication standard, wherein an antenna width is designed to satisfy radiation resistance achieving a prescribed standing wave ratio in a resonant mode in which a loop length of the metal plate antenna is 1.5 wavelength of a wireless signal conforming to the prescribed communication standard.

Abstract: There is provided a metal plate antenna that has an arch shape and transmits and receives a radio signal based on a specified communication standard, comprising: a feeding point contact portion configured to come into contact with a feeding point formed on a substrate at one end of the arch shape; and a GND contact portion configured to come into contact with a GND formed on the substrate at the other end of the arch shape, wherein an antenna length defined by a length between the feeding point contact portion and the GND contact portion is formed to be approximately ½ of a wavelength of the radio signal based on the specified communication standard.

Abstract: A positional relationship between devices that have transmitted and received signals is more accurately estimated. An antenna device used for an arithmetic operation that is based on a signal received from a certain communication device, the antenna device comprising a first antenna, a second antenna, and a third antenna at positions meeting respective vertices of an equilateral triangle.

Abstract: There is provided an antenna that transmits and receives a wireless signal compliant with a designated communication standard, the antenna comprising: a metal plate that is disposed on a circuit board; a first supporting section that supports the metal plate and connects the metal plate to a feed point formed on the circuit board; at least one second supporting section that supports the metal plate and connects the metal plate to a ground plane formed on the circuit board; and a plurality of extension sections that extend from an outer edge of the metal plate toward a direction of the circuit board but have no contact with the circuit board; wherein the plurality of extension sections operate as perturbation elements that form two excitation modes, the two excitation modes spatially intersecting with one other.

Abstract: there is provided an antenna device comprising a flat dielectric substrate a radiating element disposed on a surface of the dielectric substrate and a ground plane disposed on another surface opposite to the surface of the dielectric substrate wherein the radiating element has a size corresponding to operating frequency of the radiating element, and the ground plane has a plurality of openings that are periodically made at a pitch less than ¼ wavelength of the operating frequency.