| The receiveing front end is a core component of the receiver system,which plays an important and decisive role in the development of the overall structure and performance of the receiver system.With the increasing technical requirements on the receiver,the receiving front end is developing towards ultra wideband,minizturization,integration,low cost,automation and other production directions.In this paper,2～18GHz ultra wideband receiving front end is designed based on High Temperature Co-fired Ceramic(HTCC),and the noise coefficient is less than 5d B,the biggest g ain is more than 40 d B,and the size is 20mm×15mm×5mm.It has the advantages of low cost of miniaturication in the working frequency bandwidth.It can be used as a standardized and universal module,suitable for miniaturization and ultra wideband electronic countermersures radar receiving system.In order to realize the miniaturization of 2～18GHz ultra wideband receiving front end,this subject investigated System In Package(SIP).By comparing the advantages and disadvantages of High Temperature Co-fired Ceramic and Low Temperature Co-fired Ceramic(LTCC),the High Temperature Co-fired Ceramic with good hest dissipation performance and high chemical stability is selected as the design substrate.At the same time,the micrasaaembly technology is investigated to lay a foundation for the intelligent production of the miniaturized reception front end.Firstly,the miniaturization scheme of 2～18GHz receiving front end is designed.Design the structure of the 3D packaging system of the receiving front end,RF circuit scheme and twice frequency conversion scheme,select appropriate components,calculate the index of the receiving front end,and use ADS to simulate the system level link of the receiving front end.The simulation results are basically consistent with the calculation results,and the results show that the planning is feasible.Secongly,the high density passive circuit is designed to improve the integration of the receiving front end.The plate-level vertical interconnect based on HTCC is designed.Good signal transmission performance is obtained by optimizing simulation.Meanwhile,tolelance analysis is carried out when the displacement is 1μm.Design horizontal and vertical transition simulation of microstrip line(ML,Microstrip Line)and strip line(SL,Strip Line),and horizontal transition simulation of coaxial-microsrip line,which have good transmission charateristics within DC～30GHz after optimization.On this basis,multistage hotizontal interconnection and multistage vertical interconnection are designed.In order to verify the signal transmission,the RF signal of the lower HTCC substrate is crosstalk simulated,and the results show that the isolation between two transmission lines meets the design requrements of EMC.2～18GHz miniaturized power divider is designed.By folding the microstrip power devider,the sized of the power divider is effectively reduced.A narrow-band bandpass filter with operating frequency of 21.5～22.5GHz is designed,and an ultra-wideband bandpass filter with operating frequency of 11～18GHz is designed,the optimized performance index is good.Then,the reliability analysis of the 3D packaging structure of the receiving front end involved in this topic is carried out.The reliability of the pad is studied through constant acceleration loading analysis,the results show that the stress,strain and displacement of the pad meet its material characteristics.The modal frequency of the 3D packaging structure is obtained through modal analysis of pre-stress.The vibration frequency of the whole structure is above 30 k Hz,which is higher than that encountered in a vibration environment and normal operation.Through fatigue reliablity analysis,the life prediction model is studied to estimate the life cycle times.Steady state thermal analysis and thermal stress analysis are studied by thermal simulation,and the reliability of the receiving front end is proved.Finally,the production assembly and testing of 2～18GHz receiving front end.The performance test of the reveiving link is completed,and the test results basically meet the requirements of the performance index,and a good design result is obtained. |
