A Compact 12 to 47 GHz Variable Gain Amplifier With Low Gain/Phase Errors for 5G NR FR2

This letter presents a mm-wave variable gain amplifier (VGA) supporting the fifth-generation (5G) new radio frequency range 2 (NR FR2), implemented in an 180-nm silicon-germanium (SiGe) bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. To reduce gain and phase errors within the wideband range, a resistor–capacitor (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i>) feedback-based phase compensation technique is proposed. The proposed circuit architecture comprises a cascode low-noise amplifier (LNA) stage cascaded with a current-steering VGA stage. Measurement results demonstrate that the circuit achieves a gain adjustment range of −4.1 to 15.9 dB across 12 to 47 GHz, with a 3-dB fractional bandwidth of up to 118.6%. The measured root-mean-square (rms) phase and gain errors are less than 4.5° and 0.67dB, respectively, while occupying a core area of merely 0.1 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>.