Research On Miniaturization Of RF Filters Based On Lumped Parameter Elements

With the development of communication technology,people have a higher demand for the radio frequency system.The passive devices represented by filters occupy more than 80%of the area in the RF system.The small size,low cost and high performance of the passive devices are very important.Compared with distributed parameters,lumped parameter components are more conducive to miniaturization,and Integrated Passive Devices(IPD)and Surface Mounted Technology(SMT)are two important ways to realize lumped parameter components.In this paper,we use HR-Si IPD technology and SMT components to study the miniaturization of RF filters,which has important academic and application values.The main work and innovation of the thesis are as follows:1.The components such as inductor and capacitor are analyzed with equivalent circuit,and the model of HR-Si IPD process is verified through simulation and test comparison,which provides a good foundation for the design of IPD filters.2.Based on HR-Si IPD technology,the circuits are optimized by several methods such as combining network synthesis and network analysis and adding transmission zeros through cross coupling.Space mapping and other methods are used to optimize the layout.Two kinds of on-wafer filters applied to 5G N77 and N79 frequency bands are designed and implemented.The size of 5G N77 on-wafer filter is 2.0mm×1.25mm,the wafer test verifies the effectiveness of the design,and the size of 5G N79 on-wafer filter is 1.8mm×1.3mm,and the simulation verifies the effectiveness of the design.3.Based on HR-Si IPD technology,considering the actual situation of chip mount circuit board,a 5G N77 board-level bandpass filter is designed and implemented,then the tape-out,mount and test of N77 filter are carried out.By using the method of automatic fixture removal(AFR),the test results are de-embed and analyzed,and the results meet the design requirements and are consistent with the simulation results.4.Based on SMT technology,in order to simplify the design process,this paper consider the loss into the topology design,the synthesis method of lossy filter based on lumped parameter element is studied.Combined with the odd-even mode analysis method,a low-pass and a band-pass lossy filter based on SMT are designed and fabricated.The filter sizes are 3.5mm×6.0mm and 6.0mm×6.0mm,respectively.The effectiveness of the design is verified by experiments and comparison with the traditional design methods.5.Based on SMT technology,considering that the reflected signal of stopband may affect the system performance,the reflectionless filter is studied.Combined with the odd-even mode analysis method,low-pass,high-pass and band-pass reflectionless filters are designed by simulation.A broadband band-pass reflectionless filter is fabricated based on SMT and the size is 1.2cm×1.0cm,and the experiment verifies the reflectionless characteristics of out-of-band.