A 24.5-43.5GHz Compact RX with Calibration-Free 32-56dB Full-Frequency Instantaneously Wideband Image Rejection Supporting Multi-Gb/s 64-QAM/256-QAM for Multi-Band 5G Massive MIMO

This paper presents a 24.5-43.5GHz compact RX frontend achieving 32-56dB full-frequency instantaneously wideband image rejection, which can cover major mm-Wave 5G bands at 24.5/28/37/39/43 GHz. It utilizes a transformer-based IQ network able to accommodate large load impedance transformation with robust I/Q generation, which provides impedance up-scaling and passive voltage amplification to boost the LO swing. It achieves a low-loss mm- Wave I/Q LO generation with a compact size (0.14mm(2)) and state-of-the-art instantaneously broad bandwidth 25-50GHz without calibration or switching/tunable elements. After image rejection, the wideband desired RX signal is successfully demodulated, showing state-of-the-art 12Gb/s 64-QAM with-27.6dB EVM and 8Gb/s 256-QAM with-33.47dB EVM under wideband modulated image signals with the same modulation scheme and data rate. To the best of authors' knowledge, this paper is the first demonstration receiver frontend to support broadband modulated multi-Gb/s 64-/256-QAM image rejection with no calibration, switching/tuning elements, or external controls, enabling wideband low-latency 5G MIMOs in complex EM environments.