A D-Band Complex Neutralization Cascode Power Amplifier with A Source-Gate Driven Cascode for Enhanced Bandwidth and Efficiency

This paper introduces a new cascode Power Amplifier (PA) topology for D-band applications. The utilization of complex neutralization within the common source (CS) stage of the cascode amplifier enhances the amplifier’s gain over a broad bandwidth. Moreover, a coupled line coupler is added between the CS and the common gate (CG), allowing the CS to drive the source/gate nodes of the CG. This efficiently boosts the Psat and linearity of the PA. The stability of the PA is improved by using a series differential inductor between the CS and the coupler. A 3-stage PA with four-way power combining and an integrated Adaptive Bias (AD) is fabricated in GlobalFoundries 45nm. The measurements show a peak PG of 22.33 dB, covering a 3-dB bandwidth of 33.2 GHz (93–126.2 GHz). The corresponding Psat, OP1dB, and PAE with AD OFF/ON are 18.3/17.8 dBm, 12.8 /16.7 dBm, and a PAE of 12.4/11.1%, respectively at 120 GHz.