Silicon-based microwave coplanar waveguide BPF/BSF realization by open/short stubs

Microwave CPW bandpass/bandstop filters achieved by CPW open/short stubs have been presented. The filters are designed by a RF tool of HFSS and fabricated on a high resistivity (HR) (ρ ≥ 1000Ω·cm) silicon substrate with 1-μm SiO₂. The BPF accomplished by a dual-termination coupling open stub demonstrates low radiation with only -2.25dB insertion loss at peak transmission of 32 GHz on SiO₂/Si substrate. The BSF realized by a multi-finger short stub on a SiO₂/Si substrate has the attenuation of -17.5dB at the transmission frequency of 25 GHz. The filters have small size and good S-parameter characteristics, so they are attractive for monolithic microwave circuits (MMICs).