A 77 GHz 4-Way Power Amplifier with 20.2 dBm Output Power in 40 nm CMOS

This paper presents a fully integrated 77 GHz power amplifier (PA) in a 40 nm bulk CMOS process for automotive radar. A 4-way series-parallel power combiner using the distributed active transformer (DAT) technique is proposed to increase output power. The DAT technique reduces the loss and improved the phase/gain balance between paths. To achieve the optimal output power and efficiency, load pull matching is performed using the DAT and the connection lines. At 77 GHz, this proposed two-stage PA achieves a saturated output power <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(Pₛₐₜ)</tex> of 20.4 dBm and a peak power-added efficiency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(PAEₘₐₓ)</tex> of 18%. It demonstrates a bandwidth of 12 GHz with a peak power gain of 12dB. The core area of the PAis 0.15 mm2 and the working supply is 1.1V.