IBM Research paper “Development of a Compact 28-GHz Software-Defined Phased Array for a City-Scale Wireless Research Testbed” was presented at 2021 International Microwave Symposium (IMS2021) during a virtual Late-News Session of “Millimeter-Wave Arrays for Next Generation Wireless” on June 24, 2021. The paper is based on collaboration between IBM Research, Columbia University and Rutgers University within the COSMOS testbed development effort funded by NSF PAWR program.

The paper was among the finalists of IMS2021 Advanced Practice Paper Competition (APPC) which acknowledges “innovation of a product or system application that potentially has the highest impact on an RF/microwave product and/or system which will significantly benefit the microwave community and society at large.”

In addition, the 28-GHz software-defined phased array development in the COSMOS testbed was presented by IBM Research at one of the IMS2021 Industry Workshops “Advanced Multichip Modules and Packaging for 5G and Beyond” on June 21, 2021.

The presentations reviewed the development of a compact and highly programmable 28-GHz phased array subsystem that is currently being integrated in the city-scale COSMOS testbed for advanced wireless research and experimentation. The subsystem hardware consists of a 28-GHz 64-element state-of-the-art dual-polarized phased array antenna module (PAAM), low-noise DC-DC power regulators with a single 12-V input, current sensors and an ADC for real-time supply monitoring, a phased-locked loop (PLL) for local oscillator LO (5 GHz) generation, intermediate frequency (IF) (3 GHz)/LO splitters, IF/LO baluns, and programmable switches. All of these components are integrated in a compact (10” x 5.75”) printed circuit board (PCB), which also supports the direct plug-in of a commercial-off-the-shelf FPGA system-on-module (SoM). The IF switches and splitters couple the PAAM to 20 IF ports that enable a rich set of multiple-input multiple-output MIMO configurations, including up to 8 simultaneous 16-element independent beams in each TX/RX mode. The FPGA and associated software enable the configuration of all subsystem features from a high-level application program interface (API), facilitating MIMO millimeter-wave wireless experiments. 28-GHz channel sounding measurements using the phased array subsystem coupled with software-defined radios (SDRs) is presented as a testbed-level experiment example, as shown Figure 1.