An antenna device, comprising: a first antenna comprising a first reflecting member configured to reflect at least a portion of a first signal radiated by the first antenna; a second antenna comprising a second reflecting member configured to reflect at least a portion of a second signal radiated by the second antenna, wherein the first reflecting member and the second reflecting member are separated from each other by a spacing; and a coupling capacitor comprising a first polar plate and a second polar plate, wherein the first polar plate is on a side of a first reflecting surface of the first reflecting member and is adjacent to the spacing, and wherein the second polar plate is on a side of a second reflecting surface of the second reflecting member and is adjacent to the spacing, characterized in that the antenna device further comprises: a first capacitive member which is a separate structure from the first reflecting member and configured to be connected mechanically to the first reflecting member, with at least a portion of the first capacitive member configured to form the first polar plate; and/or a second capacitive member which is a separate structure from the second reflecting member and configured to be connected mechanically to the second reflecting member, with at least a portion of the second capacitive member configured to form the second polar plate. a first antenna comprising a first reflecting member configured to reflect at least a portion of a first signal radiated by the first antenna; a second antenna comprising a second reflecting member configured to reflect at least a portion of a second signal radiated by the second antenna, wherein the first reflecting member and the second reflecting member are separated from each other by a spacing; and a coupling capacitor comprising a first polar plate and a second polar plate, wherein the first polar plate is on a side of a first reflecting surface of the first reflecting member and is adjacent to the spacing, and wherein the second polar plate is on a side of a second reflecting surface of the second reflecting member and is adjacent to the spacing, characterized in that the antenna device further comprises: a first capacitive member which is a separate structure from the first reflecting member and configured to be connected mechanically to the first reflecting member, with at least a portion of the first capacitive member configured to form the first polar plate; and/or a second capacitive member which is a separate structure from the second reflecting member and configured to be connected mechanically to the second reflecting member, with at least a portion of the second capacitive member configured to form the second polar plate. a first capacitive member which is a separate structure from the first reflecting member and configured to be connected mechanically to the first reflecting member, with at least a portion of the first capacitive member configured to form the first polar plate; and/or a second capacitive member which is a separate structure from the second reflecting member and configured to be connected mechanically to the second reflecting member, with at least a portion of the second capacitive member configured to form the second polar plate.