Study On Stacked-lc Bandpass Filters Constructed On Multilayer Substrates

In modern wireless communication systems, microwave filters or RF filters are required to be smaller and smaller in size, and higher and higher in performance. Filters constructed on multi-layer substrates draw wide attention for the advantages of higher integration level. In this thesis, the technique for the design of stacked-LC band-pass filters constructed on multi-layer substrates is investigated. The main innovations are as follows:(1) Designing a compact second-order multi-layer dielectric structural band-pass filter with two finite transmission zeros. Circuit and multi-layer dielectric structural models are putted forward.(2) Designing a cascaded band-pass filter, proposing a method to achieve better performance by introducing a two-layers feedback capacitance. Filter performance is significantly improved,with about 50dB stop-band rejection. Pass-band transmission and reflection response performs well.Currently , multilayer substrates structural filter research has achieved a lot , but mostly confined to second-order filter prototypes, with stop-band rejection about 20dB or even lower, This thesis designing a stacked-LC second-order filter with two transmission zeros which has good performance (about 20dB rejection stop-band). In depth, achieving cascaded-filter with second-order filter, improving filter to a higher performance (stop-band rejection up to 50dB, and with 4 transmission zeros in one side of the stop-band).