Analysis and Design of Differential Complex Neutralization Power Amplifiers for Efficient-Yet-Linear High Mm-Wave Applications

This paper presents a systematic design and optimization methodology to enhance the power gain of a given device towards its theoretically maximum stable power gain 4U, U as the Mason's Unilateral power gain, over a wide bandwidth. A device-level Gain-Bandwidth product (GBW) metric is also defined to assess high mm-Wave device gain boosting. The proposed technique exploits a high-order complex neutralization embedding network on a differential power device pair. For proof-of-concept, a D-band 3-stage PA with two-way power combining is implemented in GlobalFoundries 45 nm SOI process. The measurements show a peak power gain of 21.7 dB with a 3-dB BW of 15 GHz (117-132 GHz) in a compact area of 0.116 mm2. The wideband device gain enhancement allows the PA to operate in class-AB biasing, achieving efficient-yet-linear operations at 127.5 GHz with
$\mathrm{P}_{\text{sat}}$
and OP1dB of 11.9 and 11.85 dBm respectively and a peak PAE of 15%.