Research And Design Of Miniaturized Filter Function Power Divider/balun Based On LTCC

In 2008,the design of a filtering antenna initiated the development of filtering function devices,the integration of communication systems has been greatly developed with the emergence of a series of filtering function devices.At the same time,the high frequency and miniaturization characteristics of low temperature co-fired ceramic(LTCC)process just meet the development needs of modern communication systems,so with the advancement of the fifth generation of mobile communication technology,LTCC has shown excellent application advantages.Based on LTCC process,this thesis studies the miniaturized filtering power divider and filtering balun respectively.The main contents and results are as follows:1)Analyzing the theory of multilayer strip-lines resonance,and proposing inter-stage coupling boards to increase bandwidth,a highly selective four-stage distributed filter and an ultra-wide band six-stage distributed filter are designed;Also,by combining the distributed structure and the lumped parameter structure,a semi-lumped parametric filter is designed.All this three band-pass filters are introduced crossing coupling by Z-shaped structure,thus have excellent filtering characteristics and out-of-band suppression performance,and the volume of all is less than 3 mm × 4 mm × 1.5 mm.2)Analyzing the characteristics of Wilkinson power divider,and using the lumped parameter structure to design two-way power divider and three-way power divider in S-band.Both power dividers use the unified six-port package structure,external adjustable isolation resistance,and have the advantages of low insertion loss and high isolation,the volume of both is 3.2 mm × 1.6 mm × 0.9 mm.The sample processing test is performed on the two-way power divider,which shows the designed power divider has good performance.3)Cascading the designed power dividers and band-pass filters left and right in one package device to obtain two combined filtering function power dividers:distributed +two-way and semi-lumped + three-way.Both two filtering power dividers use impedance-matched transmission lines and through holes at the connection,and have the advantages of low insertion loss,low amplitude / phase unbalance,flexible structure,wide application frequency range,the volume of both is less than 3.2 mm × 5.6 mm × 1.5 mm.4)Analyzing the phase shift theory of the multilayer strip-lines,without changing the phase,adding inter-stage coupling boards to increase the bandwidth.A four-stage distributed filtering balun is designed,based on this,adding resonant stages and designing a highly selective six-stage distributed filtering balun.Both filtering baluns have the characteristics of ultra-wide band and low insertion loss,and the volume of both is less than 2.5 mm × 3.2 mm× 0.8 mm.The physical processing test of the six-stage distributed filtering balun shows the feasibility of the structure.