Review of New Combining Techniques for Space Applications
FRAYSSE, J.-P.¹; MONFRAIX, P.¹; DENOUAL, J.-M.²; PEDEN, A.²; BOURREAU, D.²; CHEBANCE, D.³; MAIGNAN, M.^1
1Thales Alenia Space; ²TELECOM Bretagne; ³CNES

Solid State Power Amplifiers (SSPAs) are key equipments for satellite performance due to their power consumption. To minimize the latter, the efficiency of the SSPAs has to be continuously improved. One way to reach this is to develop new techniques to combine several efficient solid-state amplification devices with very low combining losses.

Moreover, new potential applications, such as active antennas in the Ku or Ka band, lead to a heavy increase in the constraints concerning the size, the weight and the cost of SSPAs. The traditional combining techniques based on two-dimensional structures with couplers are not suitable for these applications. The development of new techniques using three-dimensional structures is one solution to overcome the limits of the traditional techniques.

Besides, the increase in the operating frequencies of satellite applications in the Ka or Q band, as for payload telemetry, needs to combine several amplifiers efficiently in order to be compatible with the power handling capability of semiconductor solid-state devices.

Lately, new concepts or updated old concepts have been developed to combine efficiently several amplifiers for ground applications. Thales Alenia Space - France (TAS-F) have been studying these techniques for some years to assess their potentialities for space applications. As a result, several demonstrators have been developed.

The aim of this paper will be to review these combining techniques and their potential space applications and to give an overview of the developments managed by TAS-F in this research topic with the presentation of experimental results using three different techniques:
- Septum combiners
- Spatial power combining technique with tray architecture in a rectangular waveguide
- Radial power combining technique