- 2001-2012 IEEE. A dual-function attenuator possessing both attenuation and band-pass filtering functions is proposed. The new dual-function band-pass attenuator architecture is derived by replacing the quarter-wavelength transmission line of a conventional attenuator with a 2nd-order admittance-inverter band-pass filter. Design formulas for the dual-function band-pass attenuator are derived. A 3-b CMOS dual-function band-pass step attenuator designed using a 0.18 BiCMOS technology shows measured insertion loss of 4.4-5.9 dB, RMS amplitude error of 0.8-1.4 dB, RMS phase error of 1.9-6.7 over 36-52 GHz, input P1dB higher than 20 dBm at 44 GHz, and band-pass-filtering response with stop-band rejections greater than 18 dB at 24 and 64 GHz.