Linearity and Noise Improvements of Driver-Stage Envelope-Injection Power Amplifier With Amplitude and Phase Shaping Functions for 5G New Radio Application

Abstract

The driver-stage envelope-injection power amplifier (EIPA) consisting of the wideband linear amplifier with the envelope amplitude and phase shaping functions is proposed. This SiGe BiCMOS EIPA is implemented without the switch amplifier and the off-chip inductor used in the conventional envelope tracking circuit. To improve the in-band distortion and the out-of-band intermodulation of power amplifier, the envelope amplitude and phase shaping functions of the driver-stage EIPA are investigated to equally generate the two-tone fundamental terms and symmetrically minimize the third-order intermodulations (IM3s) by using the three-tone harmonic balance analysis. The maximum linear output power of the driver-stage EIPA with the corresponding envelope amplitude and phase shaping functions is 23.5 dBm for -30-dBc third-order intermodulation distortion (IMD3) specification. The 2.35-GHz 256-quadrature amplitude modulation Time-Division Duplexing signal with the 50-MHz bandwidth is applied to validate the usefulness of the driver-stage EIPA for 5G New Radio (NR) applications. Compared to the conventional envelope tracking PA and the dc-supply PA, the measured results show that the out-of-band noise of the proposed driver-stage EIPA is significantly reduced and the maximum average output power is increased from 21 dBm to 23.5 dBm at the -30-dBc adjacent channel leakage ratio (ACLR) specification and the ACLR and error vector magnitude are improved by 5 dB and 1.3 % at 23.5-dBm average output power, respectively.

Keywords

• Envelope injection
• envelope tracking
• envelope shaping function
• fifth generation (5G) system
• noise
• third-order intermodulation (IM3)