Abstract: A low-noise amplifier (LNA) operated at 40 GHz is designed. An improved cascode configuration is proposed and the design of matching networks is presented. Short-circuited coplanar waveguides (CPWs) were used as inductors to achieve a high Q-factor. The circuit was fabricated in a 0.13-μm SiGe BiCMOS technology with a transistor transit frequency fT of 103 GHz. The chip area is 0.21 mm2. The LNA has one cascode stage with a –3 dB bandwidth from 34 to 44 GHz. At 40 GHz, the measured gain is 8.6 dB; the input return loss, S11, is –16.2 dB; and the simulated noise figure is 5 dB. The circuit draws a current of only 3 mA from a 2.5 V supply.

Key words: low-noise amplifier,  BiCMOS,  millimeter wave,  coplanar waveguide,  matching network