A Fully Packaged 135-GHz Multiuser MIMO Transmitter Array Tile for Wireless Communications

We report a packaging approach for building mm-wave massive multiple-input–multiple-output (MIMO) transmitter arrays in tiles. A single-channel 135-GHz transmitter, having a 22-nm fully-depleted (FD)-silicon on insulator (SOI) CMOS IC for baseband-RF conversion, an InP HBT power amplifier, and a linear microstrip patch antenna array, all packaged on a low-permittivity ceramic interposer (Kyocera GL771,
$\varepsilon _{r}=5.2\,\,\text {and}\,\,\delta =0.003$
), had 27.5-dBm measured effective isotropic radiated power (EIRP) at saturation and showed 8.5% error vector magnitude (EVM) during 30-Gb/s, 64 quadratic-amplitude modulation (QAM) transmission. An eight-channel transmitter MIMO array tile module constructed on an low-temperature-cofired ceramic (LTCC) interposer, with the same antennas and ICs, after calibration and under the control of a field-programmable gate array (FPGA), had 38.5-dBm measured EIRP at saturation and showed −13-dB EVM in 1.92-Gb/s 16 QAM transmission. Steerable two-simultaneous beam transmission was demonstrated at 34-dBm peak EIRP per beam.