A rotary antenna, comprising: - a first part; - a second part rotating with respect to the first part around a rotation axis; and - a rotary joint intended to connect the first part and the second part (21, 22) of the antenna and to transmit electromagnetic signals between said parts (21, 22), having a ring sector shape with a variable opening and defining the rotation axis passing through the ring center, a plurality of radial directions (68A, 68B) extending from the ring center toward its periphery and a plurality of circumferential directions (66A, 66B, 67A,..., 67D) extending along concentric circles arranged around the rotation axis; the rotary joint comprising: - a stator intended to be fastened on the first part of the antenna and defining a surface for transmitting electromagnetic signals, perpendicular to the rotation axis; - a rotor intended to be fastened on the second part of the antenna and defining a surface for transmitting electromagnetic signals, perpendicular to the rotation axis; one of the transmission surfaces (61, 81) including primary means for delimiting electromagnetic signals and the other includes complementary means for delimiting electromagnetic signals; the rotor being mounted rotating relative to the stator around the rotation axis such that in any position of the rotor, at least a part of the transmission surface of the rotor is positioned to face at least a part of the transmission surface of the stator; in any position of the rotor, the facing parts of the transmission surfaces (61, 81) of the rotor and the stator form at least one transmission path between them for the electromagnetic signals, the transmission path being delimited (64, 84) by the primary and complementary delimiting means and extending in a circumferential direction (66A, 66B); the primary and complementary delimiting means (64, 84) assuming the form of a plurality of studs spaced apart from one another; the primary delimiting means protruding relative to the corresponding transmission surface to form at least one transmission channel (65A, 65B) extending along a circumferential direction (66A, 66B) and delimited by said delimiting means along each radial and circumferential direction passing through said channel; wherein in any position of the rotor, the facing parts of the transmission surfaces (61, 81) of the rotor and the stator form at least two transmission paths between them for the electromagnetic signals, called circumferential paths, the circumferential paths being delimited by the primary and complementary delimiting means (64, 84) and extending in a same circumferential direction (66A, 66B). - a first part; - a second part rotating with respect to the first part around a rotation axis; and - a rotary joint intended to connect the first part and the second part (21, 22) of the antenna and to transmit electromagnetic signals between said parts (21, 22), having a ring sector shape with a variable opening and defining the rotation axis passing through the ring center, a plurality of radial directions (68A, 68B) extending from the ring center toward its periphery and a plurality of circumferential directions (66A, 66B, 67A,..., 67D) extending along concentric circles arranged around the rotation axis; the rotary joint comprising: - a stator intended to be fastened on the first part of the antenna and defining a surface for transmitting electromagnetic signals, perpendicular to the rotation axis; - a rotor intended to be fastened on the second part of the antenna and defining a surface for transmitting electromagnetic signals, perpendicular to the rotation axis; - a stator intended to be fastened on the first part of the antenna and defining a surface for transmitting electromagnetic signals, perpendicular to the rotation axis; - a rotor intended to be fastened on the second part of the antenna and defining a surface for transmitting electromagnetic signals, perpendicular to the rotation axis; one of the transmission surfaces (61, 81) including primary means for delimiting electromagnetic signals and the other includes complementary means for delimiting electromagnetic signals; the rotor being mounted rotating relative to the stator around the rotation axis such that in any position of the rotor, at least a part of the transmission surface of the rotor is positioned to face at least a part of the transmission surface of the stator; in any position of the rotor, the facing parts of the transmission surfaces (61, 81) of the rotor and the stator form at least one transmission path between them for the electromagnetic signals, the transmission path being delimited (64, 84) by the primary and complementary delimiting means and extending in a circumferential direction (66A, 66B); the primary and complementary delimiting means (64, 84) assuming the form of a plurality of studs spaced apart from one another; the primary delimiting means protruding relative to the corresponding transmission surface to form at least one transmission channel (65A, 65B) extending along a circumferential direction (66A, 66B) and delimited by said delimiting means along each radial and circumferential direction passing through said channel; wherein in any position of the rotor, the facing parts of the transmission surfaces (61, 81) of the rotor and the stator form at least two transmission paths between them for the electromagnetic signals, called circumferential paths, the circumferential paths being delimited by the primary and complementary delimiting means (64, 84) and extending in a same circumferential direction (66A, 66B).