A Compact Frequency-Tunable VGA for Multi-Standard 5G Transceivers

This paper presents a multi-standard digitally controlled variable gain amplifier (VGA) for 5G phased array transceivers, designed and fabricated in 120 nm SiGe BiCMOS process. A current steering technique is used to minimize the phase variation under different gain modes. Frequency tuning is achieved by utilizing variable artificial transmission lines, capable of shifting the peak gain frequency from 28 GHz to 39 GHz in discreet steps to obtain multi-band operation with minimal footprint. The proposed VGA achieves more than 12.5 dB measured peak gain, gain tuning range of 18 dB, gain resolution of less than 1 dB with <4.5° phase variation and OP1dB > 4.5 dBm. The IC occupies area of only 0.08 mm² and consumes 45 mW.