Design of 60 GHz millimetre-wave bandpass filter on bulk CMOS

A 60 GHz integrated second-order bandpass filter using rectangular open-loop resonators was designed and fabricated on a 0.13 mum standard CMOS process. The size of the filter is 415.5 times 502.8 mum².The designed filter has a pair of transmission zeros at finite frequencies in the stopband, exhibiting good selectivity. The measured filter with the grid ground plane has a flat passband and its 1 dB bandwidth is 9 GHz (59.5-68.5 GHz).The insertion loss is about 2.6 dB and the return loss is better than 8.5 dB across the passband. The effects of various ground configurations have been studied. The design was optimised with a new slotted ground plane, and its measurement shows a 1 dB bandwidth of 9 GHz (57 - 66 GHz). The insertion loss is about 1.5 dB and the return loss is better than 9.2 dB across the passband. The new optimised slotted ground provides better than 1 dB and 0.7 dB improvement to insertion and return loss, respectively. A very good agreement between the simulation and measurement results has been achieved for frequencies up to 110 GHz. Compared with other 60 GHz CMOS bandpass filters recently reported in the literature, this 60 GHz CMOS bandpass filter has achieved all of low- insertion loss, compact size and good selectivity in one design. The ground optimised design was also implemented as part of fully integrated 0.13 mum CMOS direct-conversion transmitter.