A mm-Wave Receiver with Simultaneous Beamforming and MIMO Capabilities
This thesis presents analysis and design of overlapping multi-elements in a multi-stream beamforming-MIMO architecture to achieve higher beamforming and spatial multiplexing gains with lower number of elements compared to conventional architectures. As a proof of concept, a 4-element beamforming-MIMO receiver (RX) prototype operating at 64-67GHz enabling 2-stream concurrent reception is designed and measured. By partitioning the RX elements into two clusters and partially overlapping these clusters to create two 3-element beamformers, both phased-array (coherent beamforming) as well as MIMO (spatial multiplexing) features are simultaneously acquired. 6-bit phase shifters (PSs) with 360 phase control and 5-bit VGAs with 11dB range are used to enable steering of the two RX clusters toward two arbitrary angular locations corresponding to two users. Fabricated in a 130nm SiGe BiCMOS process, the RX achieves a maximum direct conversion gain of 30.15dB and a minimum noise gure (NF) of 9.8dB across 548MHz IF bandwidth. S-parameter-based array factor measurements verify the interference suppression and spatial multiplexing in this partially-overlapped beamforming MIMO RX.