Patent ID: 7808431
Filing Date: 2010-10-05
Classification: H01Q

Abstract:
1. An antenna apparatus capable of directivity control comprising: first to fourth antenna elements successively arranged at regular angular intervals around a central point on a same plane and respectively having first to fourth feed points, wherein said first and third antenna elements form a first dipole antenna having 8-shaped directivity in directions of said second and fourth antenna elements, said second and fourth antenna elements form a second dipole antenna having 8-shaped directivity in directions of said first and third antenna elements, an electric wave from a first direction between said first and second antenna elements is received by said first and second antenna elements, and is delayed approximately by 90 degrees in space to be received by said fourth and third antenna elements, an electric wave from a second direction between said second and third antenna elements is received by said second and third antenna elements, and is delayed approximately by 90 degrees in space to be received by said first and fourth antenna elements, an electric wave from a third direction between said third and fourth antenna elements is received by said third and fourth antenna elements, and is delayed approximately by 90 degrees in space to be received by said second and first antenna elements, and an electric wave from a fourth direction between said fourth and first antenna elements is received by said fourth and first antenna elements, and is delayed approximately by 90 degrees in space to be received by said third and second antenna elements, said antenna apparatus further comprising: a phase shifter delaying a phase of a received electric wave approximately by 90 degrees; and first switching circuit controlling a direction of unidirectivity of said antenna apparatus, wherein said first switching circuit connects said phase shifter between said first and second feed points and said fourth and third feed points, and combines an electric wave received by said first and second antenna elements and delayed by said phase shifter with an electric wave received by said fourth and third antenna elements for application to a receiver apparatus, in a first case in which said unidirectivity is controlled in said first direction, connects said phase shifter between said second and third feed points and said first and fourth feed points, and combines an electric wave received by said second and third antenna elements and delayed by said phase shifter with an electric wave received by said first and fourth antenna elements for application to said receiver apparatus, in a second case in which said unidirectivity is controlled in said second direction, connects said phase shifter between said third and fourth feed points and said second and first feed points, and combines an electric wave received by said third and fourth antenna elements and delayed by said phase shifter with an electric wave received by said second and first antenna elements for application to said receiver apparatus, in a third case in which said unidirectivity is controlled in said third direction, and connects said phase shifter between said fourth and first feed points and said third and second feed points, and combines an electric wave received by said fourth and first antenna elements and delayed by said phase shifter with an electric wave received by said third and second antenna elements for application to said receiver apparatus, in a fourth case in which said unidirectivity is controlled in said fourth direction.