A 28 GHz/39 GHz Dual-Band Four-Element MIMO RX with Beamspace Multiplexing at IF in 65-nm CMOS

Dense-aperture mm-wave MIMO RX front-ends will require simplified IF interfaces, particularly when multiple 5G NR bands must be supported. The first dual-band 28 GHz and 39 GHz MIMO RX front-end with beam-space frequency-domain multiplexing (FDM) is presented that enables concurrent amplitude/phase weighted signal combining across four elements and 28 GHz/39 GHz bands. The FDM scheme places the four beam-space outputs at four different IF frequencies. The IC includes local multi-phase LO generation in each element, consumes 516mW (32.3mW/beam/element) and occupies 14mm2 in 65-nm CMOS.