Antenna

An antenna, comprising:

• an antenna body;
• a case comprising a bottom surface and side surfaces disposed around the bottom surface, the case supporting the antenna body on the bottom surface, the case being formed of metal;
• and
• a ceiling portion disposed in such a manner to face the bottom surface of the case, the ceiling portion being in contact with the side surfaces, the ceiling portion being formed of a dielectric body, wherein
• a distance from the ceiling portion to the antenna body is shorter than a half of a wavelength of a predetermined frequency serving as a frequency to be used,
• the antenna body comprises
• a conductor portion comprising a plurality of first conductors, the conductor portion expanding along a first plane,
• a ground conductor positioned to be separated from the conductor portion, the ground conductor expanding along the first plane, and
• a first predetermined number of connection conductors extending from the ground conductor toward the conductor portion, the first predetermined number being equal to or larger than three,
• at least two first conductors, of the plurality of first conductors, are connected to the connection conductors that are different,
• the first predetermined number of connection conductors comprises
• a first connection pair in which any two of the first predetermined number of connection conductors are aligned along a first direction comprised in the first plane, and
• a second connection pair in which any two of the first predetermined number of connection conductors are aligned along a second direction comprised in the first plane, the second direction intersecting with the first direction,
• the first predetermined number of connection conductors are configured to resonate at a first frequency along a first current path,
• the first predetermined number of connection conductors are configured to resonate at a second frequency along a second current path,
• the first current path comprises the ground conductor, the conductor portion, and the first connection pair, and
• the second current path comprises the ground conductor, the conductor portion, and the second connection pair.

An antenna, comprising:

• an antenna body;
• a case comprising a bottom surface and side surfaces disposed around the bottom surface, the case supporting the antenna body on the bottom surface, the case being formed of metal;
• and
• a ceiling portion disposed in such a manner to face the bottom surface of the case, the ceiling portion being in contact with the side surfaces, the ceiling portion being formed of a dielectric body, wherein
• a distance from the ceiling portion to the antenna body is shorter than a half of a wavelength of a predetermined frequency serving as a frequency to be used,
• the antenna body comprises
• a radiation conductor,
• a ground conductor,
• a first feeder configured to be electrically connected to the radiation conductor,
• a second feeder configured to be electrically connected to the radiation conductor,
• a third feeder configured to be electrically connected to the radiation conductor,
• a fourth feeder configured to be electrically connected to the radiation conductor,
• a first feeding circuit is configured to supply reverse phase signals whose phases are substantially reverse to each other to the first feeder and the third feeder, and,
• a second feeding circuit is configured to supply reverse phase signals whose phases are substantially reverse to each other to the second feeder and the fourth feeder,
• the radiation conductor is
• configured to be excited in a first direction by feeding from the first feeder and the third feeder, and
• configured to be excited in a second direction by feeding from the second feeder and the fourth feeder,
• the third feeder is positioned at a side opposite to the first feeder in the first direction as viewed from a center of the radiation conductor, and
• the fourth feeder is positioned at a side opposite to the second feeder in the second direction as viewed from the center of the radiation conductor.