What the slip ring has to handle
- RF rotary joint for Ku- or Ka-band transmit and L-band/IF receive
- Low VSWR and insertion loss with minimal variation during rotation
- Slip ring for power to motors, encoders, GPS and active RF components
- Compact, low-profile integration to minimise radome height
- Lightweight aluminium construction
- Wide temperature range and IP65 sealing
- Continuous 360 degree rotation in both directions
Typical figures
| Frequency | Ka transmit 27.5-31 GHz; L-band receive DC-2.15 GHz; Ku downlink 10.7-12.75 GHz, uplink 13.75-14.5 GHz |
|---|---|
| Power | Up to 40 W transmit (Ka example) |
| Vswr | 1.3:1 transmit, 1.5:1 receive (Ka example) |
| Insertion loss | 0.5 dB transmit, 0.4 dB receive (Ka example) |
| Temperature | -40 C to +60 C |
| Ingress protection | IP65 |
Example figures from the published sources listed below. Your requirement may differ; an engineer will confirm against your duty cycle.
Recommended slip ring types
Standards to consider
- MIL-STD-810 - environmental test methods for military terminals
- MIL-STD-461 - EMC for military equipment
- IEC 60529 - IP code
The complete system
A slip ring rarely works alone. For satellite communication antennas (SATCOM on the move) it is usually specified together with:
- azimuth motor
- elevation motor
- servo drive
- encoder
- IMU
- RF rotary joint
Specifying these together avoids mismatched connectors, cable routes and feedback interfaces, and gives you one point of contact for the whole axis.
Common problems to design out
- RF variation during rotation
- Moisture ingress in exposed terminals
- Contact wear from continuous tracking
- Excess height or weight limiting radome design
Frequently asked questions
What does a SATCOM-on-the-move antenna need from a slip ring?
Power for azimuth motors, encoders, GPS and active RF parts, combined with an RF rotary joint for the Ka or Ku signals. Integrated assemblies save height.
Which frequencies pass through SATCOM rotary joints?
A published Ka-band design transmits at 27.5-31 GHz with a separate receive channel from DC to 2.15 GHz (L-band). Ku-band joints cover roughly 10.7-12.75 GHz downlink and 13.75-14.5 GHz uplink.
Can DC power pass through an RF rotary joint?
Some dual-channel coaxial joints carry DC on their RF conductors to power active rotating components, such as an LNA. Larger loads use a slip ring.