A 220-GHz Energy-Efficient High-Data-Rate Wireless ASK Transmitter Array

In this work, we present a wireless energy-efficient fully integrated amplitude shift keying (ASK) transmitter (TX) array at 220 GHz. Each TX cell consists of an oscillator, a modulation switch, an on-chip antenna, and baseband amplifiers. The oscillator uses a harmonic generation technique that is optimized for maximum output power and efficiency. The ASK scheme is used for data modulation and is implemented with a fast switch that does not consume any dc power. Three of these TX cells are coherently coupled together to increase the signal-to-noise ratio (SNR) and, hence, the data rate. This also enables the possibility of having a four-level spatial ASK modulation. Fabricated in a 55-nm SiGe bipolar complementary metal oxide semiconductor (BiCMOS) process, the array dissipates 165.2 mW of dc power and generates 4.2-dBm effective isotropic radiated power (EIRP). The chip demonstrates a 20-Gb/s data transmission rate with on-off keying (OOK) modulation at a 28-cm distance using low-cost Teflon lenses. The measured energy efficiency of the array is 8.26 pJ/bit. To the best of our knowledge, this work demonstrates the best energy efficiency among TX arrays at this frequency range.