A Compact 22–40.8 GHz Broadband Power Amplifier in 65 nm CMOS

Abstract

This brief presents a broadband millimeter wave power amplifier (PA) to support 5G wireless communication. The MOS-capacitor based neutralization technique is applied to boost the gain and enhance the stability of the PA. A strong coupled transformer structure is theoretically analyzed and designed to construct the output matching network, which provides the optimum load impedance of the PA over a wide frequency band and absorbs the output capacitance of the device. Meanwhile, the input and Interstage matching networks are designed based on the weakly coupled transformer technique to extend the working bandwidth of the PA. The PA is designed in a 65-nm CMOS process with a peak power added efficiency (PAE) of 30.8%, a saturated output power ($P_{\text{sat}}$) of 17 dBm, and an output 1-dB compression point ($P_{1\text{dB}}$) of 12.5 dBm. The measured PA achieves 66% fractional bandwidth (FBW) from 22 to 40.8 GHz, fully cover 5G new radio (NR) frequency range 2 (FR2). The proposed PA realizes a compact size with a core area of 0.104 mm${}^2$, making it very suitable for large-scale phased array beamformers.