A Sub-THz Full-Duplex Phased-Array Transceiver With Self-Interference Cancellation and LO Feedthrough Suppression
Chun Wang, Ibrahim Abdo, Chenxin Liu, Carrel da Gomez, Jill Mayeda, Hans Herdian, Wenqian Wang, Xi Fu, Dongwon You, A. Bahgat Shehata, Sunghwan Park, Yun Wang, Jian Pang, Hiroyuki Sakai, Atsushi Shirane, Kenichi Okada
Abstract
A sub-THz (88–136 GHz) full-duplex (FD) phased-array transceiver (TRX) integrating an RF self-interference (SI) canceller with differential feeding FD antennas is presented in this work. The LO phase generation chain controls differential transmitter outputs for the phased-array operation. The differential feeding FD antenna with differential pairs of chips achieves over 35-dB SI suppression. The SI suppression is improved by 20 dB when the SI canceller is turned on. Without any digital-domain SI cancellation (SIC), a total SI suppression of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$>$</tex-math> </inline-formula> 60 dB is achieved over a 2-GHz bandwidth. The proposed neutralized mixer with over 20-dB LO feedthrough suppression and wideband RF amplifiers support a large data rate at sub-THz frequencies. This is the world’s first demonstrated sub-THz FD phased-array TRX. In the over-the-air (OTA) measurements for FD mode, the proposed FD TRX achieves 6 Gb/s in 8PSK and 4 Gb/s in 16QAM. It also achieves a 112-Gb/s data rate for OTA TX-to-RX.