Research And Realization On Silicon-based Coplanar Waveguide RF Bandpass And Bandstop Filters

Silicon-based CPW microwave filters have were investigated. The bandpass and bandstop filters have been implemented with coupled structures on three kinds of substrates. On the HR_Si + SiO₂ substrate, the 32GHZ bandpass filter, 25GHz bandstop filters was implemented. Good filter characteristics are evidenced from the -2.25dB insertion loss at peak transmission of 32GHz. The bandstop filter demonstrates a high radiation with insertion loss at peak transmission of 25GHz. These results have great agreements with the ideal results.Based on referring to many papers, we realized the bandpass and bandstop filters with admittance inverters. To optimize the performances of the microwave filters, we put forward different substrates and metal structures after mang of simulations by HFSS8.0. These works are presented in this thesis:1. Two ports network analysis method was applied to have deeper researches on the substrates' equavilent modules. Increasing the substrate resistance and reducing the substrates' oxide thickness and coupled capacitances make a reduction of the substrate loss. However using the coupled CPW transimission lines to realize the filters, among the factors the metal layer's structure is the most important facter on performance effects. The greater the impedence of metal layer was, the better the performance of the filter was.2. The 32GHz bandpass filter has been implemented by dual-termination coupled open end-stubs. This structure improves the coupling capacitances between the center metal and matching lines. The impedance of metal layer was reduced and the insertion loss was decreased.3. The 32GHz bandpass filter has been implemented on SOI substrate. It is evident that the performance of the filter on SOI substrate is as good as that of on the Hr silicon only. That means SOI is very suitable for MMIC.