X-Band Transmitter

X-Band Transmitter

Antenna Deployment System

The aim of the X-Band transmitter is to provide a QPSK modulated downlink signal operating in the EESS band (8025 to 8400 MHz) for LEO satellite application. 

The X-band Transmitter consists of two fully cross-redundant units each including: an X-Band oscillator, a QPSK modulator, and a final power amplifier of 4 W nominal RF output power. 

The two oscillator modules are operating at center frequencies that are separated by 130 MHz to reduce ACI (Adjacent Channel Interference). 

The operating frequencies of the two oscillator modules are respectively 8120 MHz and 8250 MHz. The QPSK modulator accepts a digital video signal consisting of two I, Q data streams differentially coded with a nominal data-rate of 75 Mbps each for a total of 150 Mbps per channel. 

Each unit consists of one oscillator, a QPSK modulator and a final power amplifier that can be switched on-off independently from the other. When both units are turned on, the equipment can handle an overall data stream of up to 300 Mbps.


Physical Characteristics

Dimensions (l x w x h)

270 x 126 x 270 mmPower< 72 W (Both channel on)
Mass 4.6 KgSupply Voltage+28V
Random Vibration15 Grms (all axis)Life Time< 5 years
Operating Temperature-20°C to +60°CNon Operating Temperature-40°C to +85°C

Qualification and Acceptance Testing


Qualification TestAcceptance Test
Mechanical ShockYESOn Request
Thermal CyclingYESOn Request
Thermal VacuumYESYES
Antenna Deployment System

Data / Power Interfaces

X-Band Transmitter 2

RF Interfaces

Antenna Deployment System

RF Output Interfaces


  • Fully cross redundant units
  • Space qualified
  • Overall data stream up to 300 Mbps
  • 4W RF Output power
  • Amplifier Temperature Analogue Telemetry
  • Power Analogue Telemetry
  • Cross-strapping switch position Telemetry


  • Earth Observation Missions

Performance Properties

RF Properties:

  • 8025 MHz – 8400 MHz
  • RF Output Power: up to 4W
  • QPSK Modulation
  • Up to 300 Mbps
  • 50 Ohm Output Impedance
  • VSWR 1.5:1


  • RF: Female SMA connector
  • TLM and Supply voltage: D-sub 9 pin
  • DATA (I,Q): D-sub 9 pin