Description of a Versatile High Power Source and Load Pull Setup Developed at ESA
Andres Beivide, A; Le Gallou, N
ESTEC/ESA

The source and load pull analysis is an important tool in the design of solid state power amplifiers. A versatile passive source and load pull multi-harmonic measurement test bed has been developed in the RF Payload System Division laboratories at ESTEC. The setup is initially conceived to support the resolution of design issues related to flight ESA projects but also to support activities related to emerging technologies in the frame of R&D ESA activities. In the long term, companies of ESA member states involved in space programs are also invited to make use of it as external costumers, as a complementary tool to the characterization services available from specialized companies.

The test bed covers a wide frequency range and has a reasonable high power handling, being able to reach powers around 60W in CW mode. The key element is a multi purpose passive tuner that can independently determine the impedance of up to the third harmonic thanks to its three independent wideband probes. If three harmonics are considered, the frequency coverage is between 1.2GHz and 4 GHz for the fundamental frequency whereas the upper frequency limit extends to 12 GHz when only the fundamental frequency is considered. This makes this setup especially interesting for power amplifiers in applications such us Galileo (L band), telecom mobile (L and S band) and telecom (C band).

Besides covering the description of the blocks that form the setup and the steps to calibrate and configure it, the paper shows the remarkable capability of measuring a number of important performance metrics such as output power, gain, efficiency and harmonic and DC characteristics. Finally an example of application and some results are provided, showing that the engineer can advantageously characterize the device under test and make the most convenient decision for the amplifier design considering the trade-offs among these metrics.