Abstract
This paper presents a 21.5-to-36 GHz 6-bit radiofrequency variable gain amplifier (RF-VGA) for the fifth generation (5G) communication phased-arrays in 0.13-mu m SiGe BiCMOS technology. To maintain a wideband stable power gain and accurate gain control under all operation states, the two-stage amplifier comprising a cascode amplifier with RC compensating network and a common emitter amplifier is designed and realized. The measured results reveal a wide gain tuning range of -16 to 16 dB, a gain resolution of 0.5 dB with 6bit digital control, a minimum RMS gain error of 0.04 dB only, 3-dB bandwidth of 13.5 GHz, output P1dB compression point of 9.3 dBm, and total DC power consumption of 23.5 mW under 1.6V supply. The chip area is 0.64x0.4 mm(2), excluding the testing pads. To the best of the authors' knowledge, it achieves the best FOM among similar reported VGAs.