How a Conductive Slip Ring Works in the Antenna System


There is an increasing demand of broadband communication systems on various forms of mobile platforms, for example, maritime vessels, land vehicles and aircrafts. Each of these advance equipments is equipped with one or more radars, and each radar has a separate antenna system, mechanically driven in azimuth and elevation. With a broadband satellite communication system that has an antenna mounted on a vehicle, the antenna is used to help form a communication link with a space-based satellite in geosynchronous orbit. The antenna forms part of a communications terminal that is carried by the vehicle. Antennas with an ability to track, with high precision, communication satellites from mobile platforms such as aircraft, ships and land vehicles are required, inter alia, for optimizing data rate, improving the efficiency of downlink and uplink transmission, and/or preventing interference with satellites orbiting adjacent to a target satellite. Such antennas allow mobile satellite communication platforms that have relatively high attitude accelerations, such as aircraft and land vehicles to receive signals from and/or to transmit signals to satellites such as geostationary satellites.

The rotating antenna comprises a pedestal and a rotating base supporting at least one antenna reflector and an RF transmission/reception unit, the pedestal and the rotating base being parallel mounted, a rotary joint positioned to allow a transmission of radio frequency (RF) signals between the rotating base and the pedestal during a rotational motion of one relative to the other around a rotation axis, an encoder set to follow the rotational motion, a conductive slip ring positioned to encircle a vertical profile of the rotary joint between the pedestal and the rotating base so that an electric contact is maintained there between during the rotational motion, and an annular bearing positioned to radially encompass the encoder and the plurality slip rings around the rotation axis and to constrain the rotational motion. The rotary joint, the slip ring unit and the annular bearing are concentric and the rotary joint, the encoder, and the annular bearing being on a common horizontal plane.

The slip ring and brush block is used to transfer voltage control and status signal to and from the elevation circuits while the antenna rotates in azimuth. The application of slip ring in the antenna system is similar to pan-tilt unit. A pan-tilt device with integrated slip ring is often used to provide accurate real time positioning for the antenna too. Some high performance pan-tilt devices offer integral Ethernet/ web interface, and the conductive slip ring is required to with Ethernet transmission.

Different antenna systems require different slip rings too. Generally speaking, high frequency slip ring, platter shape slip ring (low height slip ring) and through bore slip ring are often founded in antenna systems. In recent years, marine radar with rotating antenna has quickly demanded, more and more of them require Ethernet connectivity. AOOD Ethernet slip rings allow 1000/ 100 base T Ethernet connection from the fixed to the rotating platform and more than 60 million revolutions lifetime.

Model Selection

A slip ring is an electromechanical device which in combination with brushes that allows the transmission of power and electrical signals from a stationary to a rotating structure.

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