Thermal control of a space power unit for radio frequency application

One of the most important issues of the microelectronic research and design is the thermal control. The high level of integration of these components must take a thermal control design into account specially when this technology is coupled with hybrid materials. Actually the standards design rules, such as the MIL STD 883G, foresee many limits for these electronic components; some of them are related to the minimum and maximum operative temperatures and they must not be exceeded in order to preserve the functionality during the operative life. In order to respect these design rules and to decrease the power dissipation by the Joule effect a new technological solution is proposed and studied in this paper. The idea is to have a thermal control by using the pyroelectric material which is able to convert the temperature, or a thermal flux, into an electrical charge spontaneously. The use of this kind of material is based on a constant thermal gradient to assure the continuous flux of the electrical charge. In order to know the thermal response of this device a numerical solution of the transient thermal problem is performed. The problem involves the study of a power unit, the HPA (High Power Amplifier), installed on a T/R (Transmission and Receive) module used in the RF (Radio Frequency) applications for a satellite antenna.