A 14.08 -Gb/s 256 -QAM 60 GHz Phased-Array Transceiver with Switchable Tertiary-Coil Transformer T/R Switch and Customizable-Sized Cascade Phase-Invariant VGAs

To meet the rising demand for multi-Gb/s wireless communications in dynamic scenarios, mm-Wave transceivers featuring large output power, high-accuracy beam directivity and wide gain range are essential [1]–[10]. According to the 5G NR and IEEE 802.11ad/ay standards, the phased-array transceivers usually operate in the time-division duplex (TDD) mode by sharing the antenna for both the transmitter (TX) and receiver (RX). However, the large insertion loss and narrow bandwidth of the conventional bulky <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda / 4 \mathrm{T} / \mathrm{R}$</tex> switch significantly limit the transceiver performance [1]. To reduce loss and save area, the transformer-based T/R switches have been leveraged, but they always encounter reduced TX-RX isolation and increased TRX co-design difficulties around 60 GHz [2]–[4]. Besides, for precise beam steering and low sidelobes, high-accuracy gain and phase controllers with large range are crucial. Unfortunately, for 60 GHz transceivers, their gain ranges are typically limited to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&lt;20 \text{dB}$</tex> with around <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.4 \text{dB} / 5^{\circ}$</tex> gain/phase errors [2]–[4].