RF Variable Gain Amplifier with Linear Control and Automatic Matching in 28 nm CMOS (1180)

A broadband radio frequency (RF) variable gain amplifier (VGA) enhanced with a gain control and automatic input impedance matching is presented. Due to the control loop, the gain is linear-in-magnitude vs the control input. Additionally, the control loop makes the circuit robust towards process and temperature variations of the transistors. The measured low phase variation versus control range of 3.5â—¦ and the high gain control range of 33dB make this VGA suitable for multi-antenna frontends.