O.I. Krahin, V.P. Radchenko, D.L. Ventsenostsev

Unlike other antenna classes, phased array antennas (PAA) include electronic elements, which emit heat energy during the work. Therefore heat mode arrangement is the major requirement that defines functionality of PAA. This issue is especially urgent for mobile-based active phased array antennas (APAA), where the space for cooling system deployment is limited and the density of a heat current may by about 100-200 W/cm². Depending on density of a heat current, those or the others methods of cooling system arrangements are used. For mobile systems in all cases the organization of back-to-back system is required. Also, for example, two-stage cooling systems may be used: at the first stage the heat current is taken out from modules into the internal cavities of APAA, at the second - the heat current through the general system is taken out to the outside. At the first stage may be used liquid (with the use of liquid of high heat capacity and thermal diffusivity), liquid capillary and evaporating cooling systems. At the second stage, as a rule, air or liquid cooling is used. The most perspective method of local cooling is liquid capillary method, which helps to provide direct cooling of heatloaded parts. In JSC "Radiofizika" for simulation of heat emission of transmit-receive modules (TRM) and monitoring of cooling system effectiveness the heat mockup of APAA fragment was made and tested. The experimental investigation of liquid cooling system with tubes, contacted with external side of the frame of APAA module, which was carried out, made it possible to draw a conclusion about the possibility to use this system in X-band for APAA. In addition, the results of the tests made it possible to project the ways of improvement of the mentioned liquid cooling system in a wide range of environmental temperatures. A number of issues concerned with high heat generation in APAA are emphasized in the paper on a par with the ways of solution which differ depending on operating range of wavelength.