Double HOOK: A 140 GHz 15 Gb/s Reconfigurable 3-Level ASK Modulator With Constant Input Impedance for High-Speed Connectivity

This work presents a 140 GHz D-band reconfigurable 3-level amplitude shift keying (ASK) and On–Off Keying (OOK) modulator, named “Double HOOK.” The proposed modulator features a push-push frequency doubler with integrated “Double” shunt switches at the common-emitter node, enabling reconfigurable second Harmonic OOK modulation (“HOOK”), while maintaining nearly constant input impedance, with less than 1% mismatch across different amplitude states. This characteristic makes it well-suited for next-generation short-range connectivity in a scalable array. The design is developed using a 90 nm SiGe BiCMOS process and is heterogeneously integrated with a fused silica antenna. The Double HOOK circuit and antenna system reach data rates of up to 15 Gb/s with a bit error rate (BER) better than $10^{-6}$ across bandwidth (BW) from 130 to 150 GHz, while achieving a 20 cm range. The chip occupies an area of $0.670\times 0.470$ mm, consumes an average of 40 mW of dc power, and provides 2 dBm of ${P} _{\text {sat}}$ and ~3 pJ/bit spectral efficiency.