Miniature high performance LTCC bandpass filter with multiple controllable transmission zeros

In this paper, a high-performance miniature bandpass filter with controllable transmission zeros is designed using low temperature co-fired ceramic (LTCC) process for the metrics and miniaturisation requirements of a C-band receiver front-end bandpass filter. The overall design adopts the form of lumped parameter, introducing transmission zeros on both sides of the passband through the LC blocking band-trapped resonance to improve the out-of-band rejection, and adjusting the position of the transmission zeros by adjusting the size of the capacitance. The filter is modelled and simulated in HFSS, and Simulation results show that the filter passband ranges from 4 GHz to 6.1 GHz, with the in-band insertion loss of less than 1dB, the out-of-band rejection of more than 30dB at 3.2GHz and 6.8GHz, and the size of the filter is 2mm*1.8mm*0.6mm.