60 GHz millimeter-wave compact TFMS bandstop filter using transversal resonator in 0.18μm CMOS technology

This study presents the implementation of a millimeter-wave compact bandstop filter (BSF) using the standard 0.18 μm CMOS process. The topology is based on transversal signal interference technique, obtained by connecting two transmission lines with proper characteristic impedances and electrical lengths in parallel. Sharp-rejection characteristics are obtained without using any extra resonators. Moreover, BSF having single-characteristic impedance is analyzed for design simplicity. A compact thin film microstrip structure with meandered signal line is properly constructed without any post processing steps. The overall filter occupies a compact circuit area of less than 0.25 λ_g × 0.25 λ_g and exhibits a 20 dB stopband fractional bandwidth of 21% and high-rejection of about -38 dB at centre frequency of 60 GHz. A good agreement between the predicted and measured results is observed up to 110 GHz.