Integrated Design of Millimeter-wave Bandpass Filter Chip with Lumped Parameters

To meet the requirements of microwave technology in the millimeter wave frequency band, a tiny millimeter-wave bandpass filter chip with two transmission zero points was designed. Considering the practical application, the transfer structure with coaxial vertical transition is adopted to realize the highly integration of millimeter-wave multi-layer stereo structure. The dimension of the filter chip is 0.32 mmx0.64 mm, with the center frequency of 30 GHz and the fractional bandwidth of 18.3%. Simulation results demonstrate that the in-band return loss is greater than 12 dB, and the out-of-band suppression is 18 dB at 25 GHz and 20 dB at 35 GHZ, which essentially satisfies the specifications of a bandpass filter chip.