V.А. Kolomejcev, А.V. Ezopov, A.E. Semenov

We consider the problem of heat removal from the active element of the output amplifier receiving and transmitting module active phased array antenna. Of particular relevance to this problem takes the appearance of monolithic integrated circuits microwave power amplifiers with high output - 10 - 15 W, when the level of available hardware components provides a high level of radiated microwave power, and the constructive implementation of the system of heat removal from the active element does not provide the required thermal conditions. To study the thermal regime of the active element in this paper we propose a mathematical model describing the processes of heating and heat transfer from the active element in the cooling medium. This mathematical model is an inhomogeneous internal heat conduction boundary-value problem consisting of a differential equation of thermal conductivity with appropriate boundary and initial conditions, allowing an analytical solution. The optimal approach to the internal boundary-value problem of heat conduction (IBPH), taking into account the particular structure of the monolithic integrated circuit is an analytical method for solving IBPH, which allows the use of heterogeneous IBPH solved analytically by the method of variation of arbitrary constants and representations of the solution in the form of a Fourier series in eigenfunctions of orthogonal functions, are themselves orthogonal functions as defined on the basis of analytical solutions of the homogeneous interior boundary value problem of heat conduction. The proposed Article solutions approach to the internal boundary-value problem of heat conduction is the most versatile method for complex solutions IBPH wireless devices, allowing to take into account the effect of active and passive elements on the thermal field of MIS, and to identify ways to optimize the operating conditions and reduce the maximum temperature in a monolithic integrated circuit. Furthermore, these relations allow us to investigate the pulsing MIS of interest in the development and design of RTM APAA. The paper shows the calculated dependence of the maximum heating temperature of the active element of the coefficient of heat transfer by convection and radiation into the environment under various conditions. You can see that from some of the values of the coefficient of heat transfer by convection and radiation, a much greater contribution to reducing the maximum temperature of the active element makes use of high heat reason than a further increase in the coefficient of heat transfer by convection and radiation. Thus, this study shows that the most effective way to reduce the maximum temperature of heating the active region of the output power amplifier receiving and transmitting module APAA is to increase the thermal conductivity of the base MIS.