L-Band SSPA GaN based, passively cooled, linearised L band SSPA for avionics

  • Status
  • Status date
  • Activity Code

1.         Consolidation of system-level and component-level specifications, 

2.         Development and verification of the SSPA prototype, 

3.         Development and verification of the linearizer,

4.         Development and verification of passive cooling,

5.         Achieve small size, weight, power and price


High efficiency together with stringent linearity requirements.

Support of multi-carrier transmission.

Challenging working environment.


Thanks to significant enhancement in power efficiency the SSPA can use lightweight heat sink. As a consequence, size of SATCOM terminals as well as power consumption can be reduced. 


Covers Inmarsat (1626.5 – 1660.5 MHz) and Alphasat (1668 – 1675 MHz) bands. Iridium and Antares bands also targeted (optional).

Single carrier operation

14.5 W nominal output power with min. 47% PAE at final stage.

>=45 dB linear gain

>6 dB power flexibility

<= 200 cm2 footprint

Passive cooling

1e6 hrs MTTF

-55 °C to 70 °C operational temperature range

System Architecture

System architecture consists of two key elements: 1) the SSPA which also includes driver and predriver stages and 2) the linearizer. In addition to that the system comprises of multiple supporting elements such as data converters, frequency up-conversion and down-conversion stages, attenuator etc.


Project is divided into two contractual phases. Aim of the phase 1 is to develop an SSPA breadboard incorporating heat sink, linearizer and a simple final HPA stage. Phase 2 focuses on the development of a new advanced concept HPA stage.

Main project milestones:

  • Preliminary Design Review
  • Fast Prototype Test Review
  • Critical Design Review
  • Test Readiness Review

Final Review

Current status

Project has been completed. A prototype Doherty power amplifier with DPD linearisation delivering 15W (average) / 65 W (peak) power with DPD linearisation is demonstrated. The demonstrator meets all linearity, distortion and spectral regrowth requirements with significant margin while maintaining ~50% power-added efficiency across the frequency band of interest.

Prime Contractor