CFD-modeling of the temperature field of the radiator casing of the transmitting module of the active phased antenna arrays with air cooling

Abstract

Modern radar stations are widely used to obtain images of earth surface with high spatial resolution, to identify moving objects in the air, on sea and on the ground, and allow determining the coordinates and movement parameters accurately. Active phased antenna arrays with large number of transmitting modules are widely used as antenna systems in radar stations. The heat generated by the active microwave elements of the output amplifiers of the transmitting module, leads to an increase in their temperature and to decrease in reliability. In this regard, the task of increasing the cooling efficiency of active microwave elements of the output power amplifiers is important. The aim of this study is to assess the possibilities of air cooling of the active elements of the output power amplifier in relation to the transition from gallium arsenide to gallium nitride element base with increased heat generation. This paper presents the results of computer simulation for the temperature filed of the mounting base of the radiator casing, on which 8 heat-generating elements with a local heat release of 28 W each are installed. Cooling fins are made on the opposite base of the radiator casing. The finned surface of the radiator casing is blown by an air stream with an inlet air temperature of 40°C. The simulation was carried out for three values of the air flow rate in the interfin channels: 1, 6 and 10 m/s. It is shown that the maximum temperature of the mounting base of the radiator casing is 90.1°C and is observed at an air flow rate of 1 m/s inside the interfin channels. Increasing the air speed up to 10 m/s makes it possible to reduce the temperature at the installation site of the microwave elements down to 72.1°C. A new technical solution was proposed to further improve the efficiency of the applied cooling system and to reduce the temperature of the mounting surface of the radiator casing.