A 5G FR2 (n257/n258/n261) Transmitter Front-End with a Temperature-Invariant Integrated Power Detector for Closed-Loop EIRP Control

This paper presents a multiband millimeter-wave transmitter front-end with an integrated power detector for enabling closed-loop power control. The power amplifier delivers an output power of 12.5dBm, PAE of 10% and EVM less than -25dB with CP-OFDM/64QAM/400MHz. A transformer-based PA output matching-network is proposed that presents the PA with an optimal load over the 5G frequency bands from 24.5-29.5GHz, while suppressing the second harmonic power to meet the stringent 5G emission regulation. A novel integrated power-detector (PDET) which employs a current-mode SAR ADC to improve temperature robustness of power tracking with antenna VSWR variations.