Broadband W-band power amplifier using 40 nm bulk CMOS

In this paper the design and measurement of a four stage broadband differential power amplifier intended for W-band using 40 nm bulk CMOS is presented. In order to achieve broadband performance a complex output matching network consisting of transmission line elements and transformers is employed. Furthermore capacitive cross-coupling neutralization is introduced to enhance the stability and the small-signal gain of the power amplifier, which is proofed by a small-signal calculation. The transistor dimension and matching network are optimized for the best compromise between bandwidth, output power and power-added-efficiency. Measurements show broadband characteristic from 75 GHz until 110 GHz with more than 10 dBm of output power and 10% of power-added-efficiency at 1.1 V supply voltage.