Study On Microchannel And Heat Transfer Column Structure Impact On The Heat Dissipation Of LTCC Microwave Module

Low Temperature Co-fired Ceramic(LTCC)with low cost,high resistivity,low dielectric coefficient,embedded passive components,and matching of thermal expansion coefficient with silicon,has been widely used in high density hybrid integration and microwave modules domain.However,due to the high integration and power density of LTCC microwave module continuous improvement,the thermal problem of LTCC microwave module in complex working environment becomes more and more obvious,which seriously affects the reliability of LTCC microwave module.The microchannel and heat transfer column structure in the LTCC microwave module can improve the heat dissipation problem of LTCC microwave module by controling the structure parameters.In this paper,a new type of LTCC microwave module is used as the research object,combined with the application of related scientific research projects,the influence of microchannel and heat transfer column structure parameters on the heat dissipation performance of the LTCC microwave module is studied.The main contents and conclusions are as follows:(1)Based on the study of the heat dissipation mechanism of micro channel and heat conduction column,the main structure parameters and the cooling mode of the LTCC microwave module are determined.The finite element analysis model of LTCC microwave module is established by using ANSYS finite element software,and the simulation of heat-flow coupling is carried out.Four different inlet and outlet layout modes of fluid including type Z,type I,type C and type L were carried out by simulating and optimizing analysis.The simulation results show that the overall temperature distribution of the LTCC microwave module is uniform,the highest temperature appears on the power chip,and the fluid temperature in the microchannel is the lowest.The results of four different inlet and outlet layout modes optimization showed that the LTCC microwave module power chip junction temperature in type I is the lowest,which is 50.24℃,in type C is the highest,which is 55.70℃.And the pressure loss of the inlet and outlet in type I is the minimum,which is 41.79 KPa.The pressure loss of the inlet and outlet in type Z is the maximum,which is 102.75 KPa.Therefore,compared with the other three layout modes,type I mode is better.(2)The orthogonal test design method was used to design the orthogonal test scheme of 6 factors and 4 levels for the microchannel and heat transfer column structure parameters.The simulation results with the LTCC microwave module power chip junction temperature were carried out according to the experimental scheme.Then the data validityand range analysis of the results were analyzed.The results show that within a certain range,the influence degree of structure parameters on LTCC microwave module heat dissipation performance were in turn: heat transfer column diameter> heat transfer column number> fliud inlet and outlet radius> microchannel width> microchannel height> heat transfer column height.(3)The mathematical model of the relationship between the microchannel and heat transfer column structure parameters and LTCC heat dissipation performance is obtained by using the stepwise regression analysis method based on JMP software.Then the mathematical relation model was evaluated and verificated.The data analysis results show that the model has a high fitting degree and a strong significance.The function mapping of the structural parameters and the heat dissipation performance of LTCC microwave module was described.(4)The genetic algorithm was used to optimize the mathematical model of the relationship between the microchannel and heat transfer column structure parameters and LTCC microwave module heat dissipation performance.The optimal combination of structure parameters was obtained: the heat transfer column diameter of 189μm;the heat transfer column height of 508μm;the heat transfer column number of 8 pieces;the microchannel width of 0.716mm;the microchannel height of 508μm;the fliud inlet and outlet radius of 1.047 mm.The junction temperature of the optimized LTCC microwave module power chip is 32.41℃,which is reducing 15.51%.The results show that the power chip junction temperature of LTCC microwave module is significantly reduced by optimizing,which can improve the heat dissipation performance of the LTCC microwave module.