Antenna device

摘要

An antenna device (100) includes a first antenna (10) including a first element (11) formed in an annular form and having a length defined in accordance with a wavelength of a first frequency (f1) within a first frequency band, which is predetermined. The first antenna (10) is configured to transmit and/or receive a signal of the first frequency (f1). The first antenna (10) also includes a retaining portion (12) arranged at an outer peripheral portion (11a) of the first element (11) and retains the first element (11) in a state where a plane orthogonal to an axial direction of the first element (11) conforms to a horizontal direction. The antenna device (100) also includes a second antenna (20) including a second element (21) arranged at a radially inward position of the first element (11) and configured to transmit and/or receive a signal of a second frequency (f2) within a second frequency band that is different from the first frequency band.