A 5–6-GHz CMOS Beamforming Transceiver Front-End for Fiber-to-the-Room All-Optical Wi-Fi Solution

This letter presents a 5&#x2013;6-GHz CMOS beamforming transceiver front-end with high linearity and low power consumption for fiber-to-the-room (FTTR) all-optical Wi-Fi solution, which can greatly reduce the transmission power and eliminate signal mutual interference among access points compared with traditional architecture, by aggregating beams of multichannel. The transmitter (TX) employs a high-linearity power amplifier, a variable-gain amplifier, a 5-bit passive attenuator (ATT), and a 4-bit passive phase shifter (PS). The receiver (RX) is composed of a single-to-differential variable gain low-noise amplifier (LNA), frequency-tuning buffers, a 5-bit ATT, and a 4-bit PS. Implemented in a 55-nm CMOS technology, the measured output power 1dB compression point (OP1dB) of TX is better than 12.1 dBm. The error vector magnitudes (EVMs) of the TX at 0-dBm output power with 80-MHz 256-quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal are better than <inline-formula> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula>36.3 dB, and the EVMs of the RX at <inline-formula> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula>40 dBm input power are better than <inline-formula> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula>37.8 dB. The noise figure is 4.3 dB in high-gain mode.