K‐band CMOS low‐noise amplifier with 180° phase shift function using cascode structure

Abstract

AbstractIn this study, a K‐band CMOS low‐noise amplifier (LNA) with a 180° phase shift function is presented to reduce the chip area of the beamforming system. The proposed LNA is composed of three stages, and the last stage is designed with a differential cascode structure for 180° phase shift function. The 180° phase shift function was implemented by dividing one cascode transistor into two transistors. As a result, it is possible to equip the 180° phase shift function without an additional chip area. The LNA was designed with a 65‐nm CMOS process to verify the feasibility of the proposed technique. The core size was 0.66 × 0.41 mm2. The measured phase difference between 0° and 180° phase shift modes was approximately 178° in the operating frequency of 22.0 GHz. The measured noise figure and gain were 3.8 and 12.7 dB, respectively.