5. Conclusion

In just a few decades, solid-state technologies have made enormous strides; in parallel and independently, in many systems (radar, telecommunications), peak power requirements have fallen, following the switch to digital, thanks to sophisticated signal processing algorithms, or simply as a result of the widespread use of phased-array antennas (or active antennas). These two developments have combined to push the introduction of SSPAs into markets that were long the preserve of tubes.

The latest development in solid-state technology is the switch to wide-gap materials, notably GaN. These have made it possible to increase accessible power by a factor of around 5, and to increase efficiency by 5 to 10% for the same power, thanks to the elimination of several combiner stages. GaN technologies also enable the realization of low-level functions and, in particular, excellent...