Study On The Design Technique For Transmission-Zeroes Of Bandpass Filters Constructed On Multilayer Substrates

Microwave filter is an important component in microwave communication systems. The filter performance will directly affect system performance significantly. Filter processed by LTCC or other multi-layer dielectric structural manufacturing technology draws widely attention for its advantages of higher integration level. In this paper, designing of multi-layer dielectric structural band-pass filter is researched. In-depth multi-resonator-cascaded band-pass filter are researched by theoretical analysis and electromagnetic simulation. The main job and 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 filter cascading by introducing a capacitance. Filter performance is significantly improved, with about 50dB stop-band rejection. Pass-band transmission and reflection response performs well.(3) Analysis parameters which affect filter's performance, summing up methods of how to get a high-performed multilayer substrates filter.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 paper designing a 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-60dB).