A 24.25-43.5 GHz Variable Gain Amplifier With Low Phase Shift in 40-nm CMOS

This paper presents a 24.25-43.5 GHz broadband variable gain amplifier (VGA) based on 40nm CMOS technology. The circuit architecture employs current-steering techniques to enable digital control of the gain. An additional capacitance array is utilized for phase compensation to minimize phase variation. The proposed VGA exhibits a gain adjustment range of 15.5 dB with a resolution of 0.5 dB, and achieves a maximum phase variation of 1.1° at 34 GHz. The root-mean-square (RMS) phase error is less than 1° and input 1-dB compression point (IP1dB) is greater than -9 dBm. The core area of the circuit is 0.17 mm².