Low-K BCB based 60 GHz band pass filter on Al ₂O ₃ substrate

A BCB based 60 GHz band pass filter implemented on Al ₂O ₃ substrate has been successfully designed, fabricated and tested. The CPW bended square open-loop resonator design has been adopted for its bending structure is beneficial to the size reduction. Al ₂O ₃ substrate is selected for reducing the process steps. The measurement results show a 45 GHz to 63 GHz bandwidth with an insertion loss of-1.8 dB across the band. Au and Cu filmed filter layer S-parameters are compared. The band rejection of-30 dB at 20 GHz and-20 dB at 100 GHz are observed.