Design of fractal-based CMOS bandpass filter for WirelessHD system

We proposed a fractal-based dual-mode bandpass filter (BPF) using a standard CMOS process for application of 60 GHz WirelessHD system. We first investigated the effect of coupling feedlines of I/O ports set at different layer of M3 and M4 layer on the transmission loss of the resonator, and verified the nature coupling of fractal-based dual-mode filter. Experimental result shows that the designed filter with a fractional-bandwidth (FBW) of 23%, an insertion loss about 7 dB and return loss larger than 10 dB. Additionally, two transmission zeros are appeared at the passband edges, thus much improve the selectivity of the proposed CMOS BPF. The result indicates that fractal-based structure is feasible and can meet the requirement in the mm-wave application.