A 28/38 GHz Dual-Band and Dual-Mode CMOS Power Amplifier Using Constant Optimal Load Impedance Method

This paper presents a 28/38 GHz dual-band and dual-mode power amplifier (PA) fabricated in a 90-nm CMOS process. With the proposed constant optimal load impedance (Z
opt
) method, this dual-mode PA can achieve the optimal power performance of both modes using the same matching circuit and improve the linear output power in low-power (LP) mode. In the high-power (HP) mode, the proposed PA demonstrates 23.1/16 dB small-signal gain, 18.4/17.5 dBm saturated output power (P
sat
), 24.6/22.1% peak power-added efficiency (PAE
max
), 18.1/16.5 dBm output P
1dB
(OP
1dB
) and 24.4/20.4% corresponding PAE (PAE
1dB
) at 28/38 GHz. In the LP mode, the proposed PA achieves 20.4/10.7 dB small-signal gain, 12.9/12.4 dBm P
sat
12.4/9% PAE
max
, 12.5/11.9 dBm OP
1dB
, 12.2/8.7% PAE
1dB
at 28/38 GHz.