Abstract
This paper demonstrates a broadband power amplifier (PA) with wideband impedance matching techniques and slot-balun-based power combining. A high-coupling transformer with series inductor is proposed for inter-stage wideband matching, which functions as an equivalent lowcoupling (low- k ) matching network with additional design freedom. In addition, slot baluns are also introduced for wideband input/output impedance matching and power combining with low insertion loss, simultaneously. To verify the proposed design techniques, a prototype was implemented in a 40-nm LP CMOS process with a core area of 0.3Í0.8 mm 2 . The prototype achieves a 3-dB bandwidth from 70.6 GHz to 98.4 GHz, a maximum power gain of 20.6 dB, a saturated output power ( P_{sat} ) of 13.6 dBm, and a peak power-added efficiency (PAE) of 10.5%.