Tunable pre-matching transistors

 
Reconfigurable power amplifier systems, able to switch from one frequency band to another, can eliminate the need for additional hardware. This is particularly interesting for satellite applications where every gram in redundant hardware increase the overall system cost.

Objectives
Develop a discrete tuneable pre-matching RF-Power transistor with a 20 W output power, tunability, and comparable Power Added Efficiency (PAE) to a non-tuneable transistor of similar type.

Achievements
Within this activity, an RF power varactor based on thick-film BST metal-insulator-metal (MIM) capacitors was developed. A novel varactor layout and material doping led to thermally stable, low-loss varactors. Furthermore, extensive modelling brought about an optimized mature design and a design process that enables package integration in a structured and predictable manner. This led to a successful demonstrator that met the stipulated specifications.

Benefits
A 20 W tunable pre-matching (TpM) transistor was demonstrated for the first time. It can be used in power amplifier designs to show the applicability in frequency agile system, dynamic load-modulated systems or in systems that need improved VSWR robustness. All of these properties would be very valuable for space applications. 

Further work
Based on this work an ARTES activity has been proposed. The intention of the follow-on activity is to extend the power range of this transistor and to demonstrate the use of a TpM transistor in a multi-band, multi-function power amplifier.