High power radiofrequency solid state amplifiers - Implementation parameters

After a first part presenting the classes, systems and technologies of solid-state RF power amplifiers [E 1 610] , this document constitutes the second part and deals with their implementation. The scope of applications covers all systems that need to deliver RF output power at a level that is significant in relation to the power consumed by the product in question.

If we consider current technological developments, we can see the increasing penetration of the solid state in industrial power systems, thanks to the widespread use of digital signal processing, which provides fine, rapid management of control and self-protection circuits, making them increasingly robust. The explosion in wireless telecommunications, with the development of complex signal transmission processes, has led to the increasing integration of electronic functions on semiconductor substrates, in the form of RF integrated circuits (RFICs) and complex power components, so that the power amplification function involves the entire development chain, from component to complete system.

The design of RF amplifiers must satisfy the requirements of each specific application, and therefore meet definition criteria that will guarantee, with greater or lesser relative importance, power, efficiency, and possibly gain and linearity. These characteristics derive from a number of implementation parameters that the designer will have to specify when developing the product: choice of amplifier type (see [E 1 610] ), application of stage supply voltages (polarization), load management (impedance adaptations), thermal treatment (cooling system) and electromagnetic compatibility (shielding). In general, this is not done without addressing the predictive reliability aspect, given that this sub-assembly is the most sensitive in the system.

The definition of these parameters presupposes a good knowledge of the components to be used, and the following tools are available for this purpose:

• manufacturer's specifications: certain quantities are established by the manufacturer for the intended use of the component, and generally do not need to be recharacterized:...