Five-pole LTCC cavity filter for wireless applications at 34GHz

System-on-Package (SOP) is presently the most effective method for realizing the miniaturization of wireless front-end applications. Band pass filter is one of the most important components in the SOP. In this paper, a 5-pole band pass cavity filter consisting of via walls was designed as a system-on-package solution for RF front-end modules at 34GHz, adopting low-temperature co-fired ceramics (LTCC). The BPF is vertically made up of five cavity resonators with via walls and has been simulated and optimized by Ansoft HFSS. This filter which has been realized in a seven layers ceramic substrate exhibits an insertion loss of 0.89 dB at the center frequency of 34 GHz, a rejection <;37.5 dB(32.9GHz and 35.8GHZ), and 3dB bandwidth approximately 4.5%(~ 1.5 GHz). Due to its vertical structure, this filter shows promising application potentials in miniaturized SOP.