| Active Phased Array Antenna(APAA) contains lots of T/R modules, which are sensitive to the temperature and in which exist plenty of random distribution heating devices. Unreasonable temperature distribution would affect phase control precision seriously. Meanwhile, thermal deformation would also lead to great changes in the antenna radiation pattern, as a result, the electric performance can’t reach the standard required, or even impossible to achieve, therefore, efficient cooling system is indispensable for APAA. As a mature and efficient heat transfer equipment, liquid-cooled cold plate could effectively solve the heat problem in APAA, and it has a broad prospect in the application of the thermal design of electronic equipments.1. In this paper, a coupling design method of cold plate channel of Active Phased Array Antenna based on device position was proposed. The specific design steps of this method are just as below. First, based on the position of the devices with high thermal power consumption in T/R modules of the APAA, combined with the principle of adding auxiliary points and making sure the channel is right under the heating chips, design the topology of cold plate channel and make the geometry model of the cold plate clear. Then establish the finite element model of the antenna array. Secondly, according to the heat consumption of the various devices in T/R modules of the APAA, compute the temperature distribution in the surface of the antenna array. Analyze the structural deformation of antenna array caused by temperature, moreover, analyze the amplitude error and the phase error of the excitation current caused by the changes of temperature. Then calculate the electrical properties of the APAA. Finally, repeat the above steps by modifying the geometric parameters of the channel section to make sure the gain performance meet the requirement. Therefore, the optimal design of cold plate of the APAA is completed.2. Based on the lightweight requirements of the avionics module, a thermal optimized design of the antenna cold plate was proposed in this paper. The main steps of this method are just as below. Analyze the characteristics of the cold plate to simplify the model. Before the optimization, make an analysis of the thermal parameters, then determine the entry location of the coolant and which type of coolant willed be used. After that, build the mathematical optimization model. In detail, take the mass of the cold plate as optimization goal, take the variables whose influence on the mass are significant as optimization variables, and then select the appropriate optimization method. According to this optimization, make sure the cold plate achieve the lightweight on the basis of meeting the requirements of the thermal design. In this chapter, by taking the inlet flow velocity of the coolant and the geometric parameters of the channel section as optimization variables, the mass of the antenna cold plate reduces 0.279 kg.3. Furthermore, the influence of the T/R module temperature on the electrical properties of the antenna was simply studied, including the impact of the maximum temperature and temperature uniformity on the electrical properties of the antenna. The result of the analysis shows that the influences of different types of T/R module on the electrical properties of the antenna are different. What’s more, during the thermal design of the APAA, the highest temperature requirements and temperature uniformity requirements are determined by ensuring the electrical properties of antenna. According to the analysis in this chapter, the maximum temperature requirements of the Ku-band, X-band and L-band APAA are 73 °C, 82 °C and 89 °C respectively, and the allowable maximum temperature differences are 3.95 °C, 5 °C and 8 °C. |
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