The Fabrication And Property Investigation Of Magnet-Core Solenoid Microinductors By Multi-material 3-Dimensional Printing

Direct ink writing,as an important branch of the field of additive manufacturing,has a wide range of available materials,high printing accuracy,and can realize the manufacture of complex three-dimensional structures.It has shown great advantages in the manufacture of micro-inductors that can be used in RF circuits.Conductive inks and soft magnetic inks that can be used for direct ink writing are prepared,and a high-precision multi-material 3D printer is used to realize the manufacture of a solenoid-type micro-inductors.The inductors can meet the requirements of RF circuits.The main research work of this paper is as follows:(1)The silver ink was prepared,which can be printing with 10 μm nozzle,and has good conductivity after annealing.Two soft magnetic materials,ferrite composites and permalloy composites were prepared,and the properties of the two materials were investigated.As inks for direct writing 3D printing,they have good rheological properties.Stable structure,low coercivity as soft magnetic material and residual magnetization,effective magnetic permeability working range is 5-10 GHz.(2)A multi-material printing and positioning method with micron-level accuracy is proposed,using nano-silver ink as conductive ink and soft magnetic composite material as magnetic core material.The structure of the device is controllable(both length and width can be in the range of microns),the preparation process and the required equipment are simple,and it can meet the requirements of RF circuits for integration and miniaturization.(3)Depending on the structure of the multi-material 3D printed inductor and the core material,the inductance value and quality factor of the inductor are also different.The inductance of the inductor with ferrite composite core is 1.5-11 nH,the resonance frequency at 15 GHz,the presence of ferrite composite cores increases the inductance value by about 20% in the 5 GHz range.Inductors with permalloy composite cores have an inductance of 3-42 nH and a resonance frequency at 12 GHz,the presence of the permalloy composite core increases the inductance by about 30%.