Low Temperature Sintered Composite Dual Performance Materials And Its Application In Filter

With the rapid advancement of electronic information technology,in particular,the development of high speed,low consumption,and broadband and integration network,low temperature co-firing ceramic(LTCC)system encapsulation and passive integrated device have become the inevitable choice for the 4th-generation(4G)or 5G cellular network technology and base station electronics.However,it is difficult to break through the electronic material cut-off frequency limit and to solve the problems associated with LTCC process involving co-firing of the porcelain with multilayer magnetic ferrite and the electronic ceramics(inductance and capacitance),which constitute the main bottleneck requiring urgent attention.Therefore,development of a new type of LTCC electronic material,which can be used as both inductor material and capacitor material in the same frequency domain with relatively low dielectric loss and magnetic loss,is urgently required.Such an LTCC material is denoted as composite magnetoelectric dual-performance LTCC material.Currently,this composite dual-performance LTCC material is the groundbreaker in achieving ultra-wideband passive integration devices by breaking through the high frequency ceiling.It is formed using the ferrite and electronic ceramics via the interdoping and substitution of ions and the growth of dual-phase crystal texture.For the radio frequency regime development,NiZnCu ferrite and BaTiO3 electronic ceramics composite,with low melting point is adopted as low temperature sintering co-solvent.In contrast,in case of microwave regime development,the material adopts gyromagnetic ferrite and microwave ceramic composite,with low melting point glass as low temperature sintering co-solvent.The new dual-performance material can not only break through the upper limit of cut-off frequency of the passive integrated device in the radio frequency segment of mobile phone,but also significantly reduce the loss of communication of microwave base station devices,and also solve the bottleneck of inductive and capacitive interface fusion and co-firing in LTCC process.In this study,the NiCuZn ferrite with low temperature sintering was used as the principal part,perovskite dielectric ceramics as attachment,and the double diffusion doping composite dual-performance material with NiCuZn ferrite and perovskite dielectric ceramics was studied.First,the effects of dual-performance composite integrating NiCuZn ferrite and BaTiO3(0-15 wt.%)on the phase formation,microstructure,and magneto-electric properties were evaluated.With the increase in the content of BaTiO3,the diffraction peaks of BaTiO3 phase were more obvious,and no other heterophase peak appeared;moreover,the grain size and density decreased gradually.The magnetic properties,such as saturation magnetization,of NiCuZn/BaTiO3 composites gradually deteriorated with BaTiO3 content,and permeability decreased rapidly.Nonetheless,the dielectric constant and dielectric loss were improved.Then the effects of Bi2O3,Li2O-B2O3-Bi2O3-SiO2(LBBS)glass,and Li2O-Al2O3-Bi2O3-SiO2(LABS)glass(0-1.5 wt.%)on NiCuZn/BaTiO3 dual-performance composite material were studied.The experimental result showed that Bi2O3 could significantly improve the microstructure and magnetoelectric properties of the dual-performance composite.The grain size,density,saturation magnetization,and permeability of dual-performance composite increased significantly with Bi2O3 content.Furthermore,coercivity decreased and dielectric constant and dielectric loss increased slightly.Moreover,LBBS glass and LABS glass were found to be responsible for improving the performance of NiCuZn/BaTiO3 composite.The effect of sintering aids in improving microstructure and magnetic properties of NiCuZn/BaTiO3 composites is in the following order:Bi2O3>LABS>LBBS,and improvement of dielectric properties:LABS>LBBS>BiO23.Second,NiCuZn ferrite was used as principal part and CaTiO3 as attachment to allow for mutual diffusion doping.The effects of CaTiO3 content(0-20 wt.%)in NiCuZn/CaTiO3 dual-performance composite on the phase formation,microstructure,magnetic properties,and dielectric properties were studied.The density,grain size,saturation magnetization,and cut-off frequency gradually decreased with CaTiO3 content;however,the permittivity first decreased slightly and then increased gradually.Next,MgO-Al2O3-Bi2O3-SiO2(MABS)glass was added into NiCuZn/CaTiO3 composite.When content of MABS glass was increased from 0 to 1.5 wt.%,the grain size,density,saturation magnetization,permeability,and dielectric constant of these dual-performance composites augmented,and the dielectric loss reduced.When MABS glass content was increased to 2.0 wt.%,the grain size,density,saturation magnetization,permeability,and dielectric constant of the composite reduced,while the dielectric loss increased.Therefore,the optimal addition amount was found to be 1.5 wt.%.Finally,the properties of NCZF ferrite and Nd-doped BNTO and CNTO composite were studied.The dielectric constant of ceramic decreased with Nd doping,but Q×f increased significantly.The content of Nd-doped ceramic was 10 wt.%,and the comparison of the permeability of the composite is as follows:CNTO>BNTO>CTO>BTO,dielectric constant:BTO>CTO>CNTO>BNTO,and dielectric loss:BTO>CTO>BNTO>CNTO.Moreover,based on NiCuZn/BaTiO3 system,composites formed by replacing part of NCZF ferrite with Co2O3 and replacing BTO with CaCu3Ti4O12(CCTO),respectively,were studied.The addition of Co2O3 resulted in the formation of hybrid phases Ba2Ti9O20 and Ba6Co4O12.However,the addition of Co2O3 also caused the increase in grain size and density of ferrite.The increase of Co2O3 content and the decrease of NCZF ferrite content resulted in slight decrease in saturation magnetization and permeability;however,cut-off frequency and Q value increased significantly.Moreover,the addition of Co2O3 reduced the dielectric constant and dielectric loss of the material.The addition of CCTO did not produce obvious impure phase,and when the content of CCTO reached 5 wt.%or above,the content of BTO decreased to 5 wt.%or below,and the magnetic grain size,saturation magnetization,and magnetic permeability increased significantly,and the number of pores and coercivity decreased.However,Q value was affected,and the high Q value band became narrower and moved to the low frequency region.It also caused reduction in the dielectric constant;however,when the addition amount was below 5 wt.%,the dielectric loss of materials was reduced.Finally,a 150 MHz low-pass filter was designed herein.ADS circuit simulation and HFSS three-dimensional model simulation were applied to optimize the filter structure,and the simulation results met the requirements of the design index.Subsequently,the dual-performance composite material studied herein and LTCC process were used to produce a 150 MHz low-pass filter based on the type of 0805 series.The attenuation at 150 MHz frequency was less than 3 dB,and the attenuation at 350 MHz frequency was more than 20 dB.This result proves that the dual-performance of new composite material is excellent.