A Broadband 241-306 GHz Frequency Multiply-By-24 Based Coherent Radiator Delivering +26.5 dBm EIRP in 90-nm SiGe BiCMOS

This work presents a fully-integrated 230-310 GHz coherent radiator for the 300 GHz band. Integrated with an on-chip dipole antenna, the proposed radiator utilizes a frequency multiply-by-24 chain (FMC) to upconvert a low-frequency LO input to the 300 GHz band. The FMC is realized using a cascade of three push-push frequency doublers, followed by a differential 300 GHz frequency tripler. A radiator prototype is implemented in GlobalFoundries 90-nm SiGe BiCMOS, and free-space chip measurements are shown. Consuming 148 mW DC power, the prototype demonstrates state-of-the-art 29.6% tuning range, peak EIRP of +26.5 dBm (with lens) at 267 GHz, 6-dB bandwidth of 241-306 GHz, and 1.2% DC-to-THz efficiency. Harmonic spectral purity is characterized, and the prototype demonstrates 26.5 dBc mid-band harmonic rejection. The proposed radiator is integrated with a 24x FMC, covers most of the 300 GHz band and demonstrates state-of-the-art tuning range and EIRP.