A millimeter-wave CPW CMOS on-chip bandpass filter using conductor-backed resonators

A novel millimeter-wave 35-GHz bandpass filter using coplanar waveguide structure is fabricated in a 0.18-μm standard complimentary metal oxide semiconductor process. The conductor-backed half-wavelength resonators are utilized to realize stopband characteristics at desired frequencies. A series $LC$ resonant circuit can generate one transmission zero located at 58 GHz. It is also observed that the parasitic effect can create another transmission zero at 80 GHz. Furthermore, the transmission zero at 66 GHz is designed with the use of a shorter conductor-backed resonator. The selectivity of the proposed filter is much improved. Without including the dummy metal, the chip size of the proposed filter is 0.225 × 0.55 mm². The good agreement between simulation and measurement is obtained.