Integration of miniaturized balun and low‐noise amplifier for single‐in differential‐out applications

Abstract

A low-noise module comprises a low-noise amplifier and a new type of passive balun, which consists of two k/8 broadsidecoupled lines and a short redundant line, is presented. The on-chip balun is not only low lossy and compact size but also provides good amplitude and phase balances at output ports over a quite wide frequency range. The method of designing the new-type balun fabricated with CMOS IC technology is proposed. An experimental prototype operated at K-band was designed and fabricated with a commercial 0.18-lm CMOS technology to verify the effectiveness of the proposed design method. The measured results show the single-to-differential gain is about 9 dB, the amplitude imbalance of the output ports is less than 1.0 dB associated with the phase difference of 181 6 3 over the frequency range of 20-40 GHz. The area of the prototype including the RF probe pads is about 0.73 Â 1.28 mm 2 .