140 GHz Multi-Channel Software Defined Radios

Background of the Small Business: Pi-Radio is a Brooklyn-based startup, making millimeter wave software-defined radios (mmWave SDRs). Pi-Radio has developed, calibrated, and tested a 4-channel fully-digital SDR operating in the unlicensed 60 GHz band. The baseband subsystem is based on the Xilinx RFSoC, and the Pi-Radio RF transceiver board features commercial 60 GHz parts from Analog Devices. Background of the Research Institution: The DARPA JUMP/ComSenTer project has funded the development of multi-channel 140 GHz TX and RX modules at the University of California at Santa Barbara (UCSB). Specifically, Prof. Mark Rodwell’s group has developed a 140 GHz transmitter IC and a 140 GHz receiver IC in CMOS. His and Prof. Jim Buckwalter’s groups have developed advanced 140 GHz power amplifiers (PA) in Indium Phosphide (InP) as well as other receivers. These ICs are currently being packaged into an 8-channel TX module (CMOS + InP), and an 8-channel RX module (CMOS only), using an LTCC substrate/interposer. Critically, these modules are fully-digital, providing baseband I/Q signals to and from each channel are independently available for processing. This Effort: This DARPA SBIR Phase-II effort aims to mate the 140 GHz module development efforts at UCSB with the SDR development efforts at Pi-Radio. Specifically in the Base period of this effort, the 8-channel 140 GHz TX and RX module designs from UCSB will be used to manufacture 18 units of each. These modules will be used to create an 8-channel transceiver (TRX) board that can mate natively with the Xilinx RFSoC-based ZCU111 board. The resulting system represents an 8-channel 140 GHz SDR that can then be used for systems-level experiments in the domains of communications and sensing. The Pi-Radio device drivers and reference examples will be ported over to the 140 GHz system. Twelve such 8-channel TRX boards will be provided to DARPA for distribution. In the subsequent Option period, four units each of the 8-channel TX and RX modules (left over from the Base period) will be tiled together to create a single 32-channel TRX board. This will be mated with a specially designed baseband subsystem in order to create a 32-channel fully-digital SDR. The architecture has been specifically designed to be scalable, such that multiple such units can be combined together to create SDRs having an arbitrary number of channels (in multiples of 32). After testing, this 32-channel TRX board will also be given to DARPA for distribution.