Wireless links at sub-THz bands require low-SWaP SDR modems. We report early design experimentation of an SDR operating in the 130-150 GHz band, with ASK/BPSK/QPSK modulation on I/Q channels, at a maximum data rate of 128 Mbps. The design utilizes 110-170 GHz front-ends from Virginia Diodes, and Xilinx RF-SoC ZCU-111 for DSP operations. A 1 GHz baseband example at 145.5 GHz is provided. The experiment uses horn antennas with 21 dB gain. The SNR is about 40 dB without cross correlation gain in the detector which provides an additional 15 dB in link margin. Real-time bit rate of 128 Mbps is achieved. Example applications include vehicle-to-vehicle, vehicle-to-infrastructure, backhaul, device-to-aerostat. This paper provides a platform from which further design work will lead to increased data rate and/or range, and enhance security through encryption. Future designs will facilitate digital interfaces, such as, ethernet, AXI, PCIe and USB-C.
