A 187–224-GHz 20-dB-Gain 4.5-dBm-Psat Power Amplifier with Dual-Band Matching Networks and Slotline Combining in 40-nm CMOS

A CMOS power amplifier (PA) optimized for high gain, high-power, and broadband operation is proposed for sub-THz radar applications. The transistor layout is optimized to enhance both maximum oscillation frequency (fmax) and output power. An interstage matching network based on a modified transformer T-model is proposed to achieve a dual-band response. Moreover, a slotline-based power divider/combiner with greater design freedom is proposed to facilitate broadband impedance matching and power division/combination. By integrating the dual-band impedance matching networks with the single-band power divider/combiner, the PA achieves broadband operation, effectively alleviating the gain-bandwidth trade-off near fmax. Fabricated in a 40-nm CMOS technology, the proposed PA achieves a measured 20-dB gain and a saturated output power of 4.5 dBm at 194 GHz, with a 6-dB bandwidth of 187–224 GHz. To the best of the authors’ knowledge, this work demonstrates the broadest reported bandwidth for a CMOS PA operating beyond 200 GHz.