This antenna includes a first part, a second part rotatably mounted about a first axis, and a rotary joint arranged between the first and second parts, the second part including a radiating source and a reflection assembly having a reflector defining a reflector top, a focus, and a second axis passing through the reflector top and the focus, the rotary joint being able to transmit electromagnetic signals between the first and second parts via at least one transmission channel, and the first and second parts being so arranged that in any position of the second part and the reflection unit, the first axis is perpendicular to the second axis.