Research On Transmission Structure Of DC?20GHz Ultra-wideband Surface Mount Ceramic Package Based On HTCC Technology

Ceramic packaging has the characteristics of high mechanical strength,strong heat dissipation,excellent microwave performance and good sealing performance.As a relatively mature ceramic packaging technology,high temperature co fired ceramic technology is not only used in aerospace and military equipment,but also widely used in automotive electronics,communication electronics and other consumer markets.Because it is made of multilayer ceramic substrate by stacking and sintering,the microwave integrated transmission lines such as stripline,microstrip line and coplanar waveguide line can be printed on each layer of ceramic substrate,and the layers are interconnected through vias,so as to improve the packaging density.However,in its multi-layer interconnection structure,the transmission lines are not simply stacked,but to do a good job in impedance matching.Therefore,the research on the transition structure and transmission performance of the transmission line in the high temperature co fired ceramic package is the basis to ensure the normal operation of devices and circuits,and also the focus of this paper.Based on HTCC technology,HFSS simulation software is used to build the transmission line model.From the simple microwave basic transmission structure to the planar same layer transition transmission structure and then to the different layer vertical transmission transition structure,the complex structure model of transmission path in ceramic packaging design is simulated and optimized.In addition,this paper also makes a detailed analysis of BGA vertical transmission structure,mainly from the modeling shape of the solder ball,the height of the solder ball and the size of the pad.It is found that the shape of the solder ball is not the main factor affecting the simulation results,but there are still small differences,because BGA also follows the coaxial transmission mode when transmitting signals,the change of the shape of the solder ball will inevitably affect the capacitance value in the equivalent circuit,and then affect the transmission effect;the height of the solder ball will directly affect the inductance value in the equivalent circuit;the size of the pad will directly affect the transmission effect Response to the capacitance of the equivalent circuit.Finally,a CQFN surface mount ceramic package shell is developed,which is5.5mm × 5.5mm × 0.64 mm in size,in the DC ? 20 GHz band,the return loss is-18 d B and the insertion loss is less than 0.7d B,.The test data of the sample is in good agreement with the simulation,and has passed the preliminary reliability test and chip loading verification.