Research On Integrated Technology Of RF Filtering And Power Division

With the rapid development of modern communication system and integrated circuit technology,the system integration is getting higher and higher,which puts forward new requirements and challenges for the miniaturization and high performance of microwave RF devices.Filter and power divider,as two common devices in RF circuits,occupy a large size in RF front-end circuits,so the filter power divider which combines the two functions has been widely concerned.Based on the above background,this thesis combined coupling theory and multi-mode technology to design two high-isolation filter power splitters that integrate the functions of filtering and power distribution,and through simulation and measurement,meet the needs of miniaturization,high performance and high integration.The main research work and innovation of this thesis are as follows:1.A 3D integrated filter power divider with multi-resistance isolation network is designed.The filter structure replaces the λ/4 wavelength line in Wilkinson power splitter to achieve the filtering performance and power fraction characteristics,and has a wide range of stopband suppression.By designing a suitable vertical transmission structure,the two filter structures are placed on the upper and lower substrates respectively,and the design mode is changed from plane to three-dimensional,which effectively reduces the structure size.The isolation performance in the passband is enhanced by designing multiple resistances between the two filter structures.The step impedance resonator(SIR)is used in the filter structure to enhance stopband suppression and reduce the size of the resonator.Finally,good passband characteristics and stopband suppression are achieved.Finally,a filter power divider made of uniform impedance resonator(UIR)is designed and compared with the same technology.2.A high-isolation multi-mode SIW filter power divider with embedded isolation network is designed.Because SIW structure is more suitable for high-frequency system,SIW-based filter power divider is widely used in antenna and amplifier feed network,etc.However,additional circuits are usually required to design isolation network in SIW filter power divider.Increases circuit size and affects performance.In this paper,the embedded capacitive isolation network is introduced into the SIW resonator,which can achieve better isolation with only one resistor and hardly increase the structure size.At the same time,the open branch loaded resonator is embedded in the SIW resonator to achieve multi-mode resonance.The multi-mode technology and folding SIW resonator are used to achieve good band-pass filtering response and effectively reduce the structure size.