A 150 GHz Lens-Free Large FoV Regenerative 2 x 2 Transceiver Array With 31% DC-to-EIRP Efficiency and-70 dBm Sensitivity for a 70 cm Bidirectional Peer-to-Peer Link

This article presents a 150-GHz regenerative low-power miniature two-way radio integrated with on-chip antennas. The low-power radio is based on a reconfigurable fundamental oscillator array that can be used as a sub-terahertz (THz) source in the transmitter (Tx) mode and a sub-THz super-regenerative detector in the receiver (Rx) mode supporting ON-OFF keying (OOK) modulation. The oscillators are coupled through a low-loss integrated Marchand balun-based coupling network that guarantees far-field constructive interference at the Rx side. A 2 x 2 on-chip patch antenna array is designed with a new adaptive metal-fill placement methodology that largely reduces antenna losses and off-tuning present in sub-THz/THz frequency antenna designs without the need for bulky silicon lenses. Our proof-of-concept prototype achieves a maximum EIRP of 8.52 dBm at a frequency of 149 GHz, an Rx sensitivity of -70 dBm, and a dc-to-EIRP efficiency of 30.7% with no silicon lens, which is the highest efficiency reported of all the siliconbased sub-THz transceivers (TRxs) in the 150-GHz range. The moderate 2 x 2 array size with no silicon lens offers a large field of view (FoV) of +/- 40 degrees, which eases node finding and link establishment in deployment. Our miniature low-power radio prototype consumes 11.6 mW in the Tx mode and 10 mW in the Rx mode after duty cycling. Wireless peer-to-peer network measurements with OOK modulation using a 10-Mb/s data rate demonstrate a chip-to-chip communication distance of 70 cm and BER <= 10(-5) at/above -55-dBm received power and a BER of 6 x 10(-3) at -70-dBm received power. The prototype chip was designed using the Global Foundries 45-nm silicon-on-insulator (SOI) process, and it occupies a total chip area of 2.1 mm x 2.1 mm, including the antenna array, making it particularly apt for ultra-miniaturized, high-security, and stealth Internet-of-Things (IoT) nodes for intelligent edge networks and wearable devices.