Design and prototype of a 60 GHz variable gain RF amplifier with 90 nm CMOS for multi-gigabit-rate close proximity point-to-point communications

Abstract This paper presents the implementation of a low-power and variable-gain 60 GHz millimeter-wave CMOS Amplifier designed for short-range multi-gigabit close proximity point-to-point communications. The design uses coplanar wave transmission lines to achieve 50 Ω input and output matching. Realized in a 90 nm CMOS process, the variable-gain VGA exhibits power consumption ranging from 4.7 mW to 39.1 mW, with gains spanning from 5.5 dB to 12.4 dB at 60 GHz and a 3 dB bandwidth exceeding 14.4 GHz. Input and output return losses remain below –10 dB across the gain spectrum. Successful demonstration of gain controllability further validates the circuit’s performance. The compact VGA die, inclusive of pads, has dimensions of 740 μm by 920 μm, thereby occupying a core area of 0.2 mm2. This design demonstrates the potential of low-power, high-performance VGAs in enhancing millimeter-wave communication systems.