To provide an antenna device, capable of narrowing a half value width in a horizontal plane while maintaining an outer diameter size of a base station antenna.
The antenna device includes: a first antenna element and a second antenna element disposed in parallel to face each other; and reflector plates disposed to face each other in parallel with both a virtual plane including the first antenna element and the second antenna element and a virtual plane including a first passive element and a second passive element. The first passive element is disposed in parallel with the first antenna element to face thereto on the virtual plane including the first antenna element and orthogonal to the reflector plate, at the opposite side of the reflector plate across the first antenna element. The second passive element is disposed in parallel with the second antenna element to face thereto on the virtual plane including the second antenna element and orthogonal to the reflector plate, at the opposite side of the reflector plate across the second antenna element. The element length of each passive element is 1.02 to 1.19 times as long as the element length of each antenna element.
YAGI HIROKI
CHO KEIZO
Yukio Nakamura
Yoshimura Munehiro
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