CMOS Variable-Gain Low-Noise Amplifier Adopting Transformer-Based Noise Cancelling Technique for 5G NR FR2 Applications

This study presents a complementary metal–oxide–semiconductor (CMOS) variable-gain low-noise amplifier (VGLNA) employing a transformer-based noise cancelling technique, applicable for fifth-generation new radio frequency range 2 communication. In the proposed design, gain controllability is realized by combining the in-phase main and current-steering path signals through a transformer load whose coupling coefficient is less than unity. Additionally, the noise contribution from cascode devices can be diminished through a transformer-based noise cancelling technique in low-gain modes. Consequently, an enhanced noise performance is achieved as the gain of the VGLNA is lowered. The proposed design is fabricated in a 65-nm CMOS process. At 28 GHz, the implemented VGLNA attains gains and noise figures of 12.1 to 2.7 dB and 3.55 to 4.3 dB, respectively. The design draws a bias current of 10.6 mA with a 1 V nominal supply and occupies a die size of 0.13 mm2, excluding bonding pads.