An Ultra-broadband Multi-color SiGe transmitter for THz Spectroscopy

This article presents a multi-color transmitter for THz spectroscopy. To achieve a decade of operational bandwidth, two parallel frequency multiplier paths with different multiplication factors are employed to cover the spectrum via harmonic interleaving. The input LO signal to the chip ranges from 27 to 36 GHz, which is input to a frequency tripler and then a Gysel power divider to split the frequency-tripled signal into two paths. The first path includes another tripler that raises the frequency to approximately 300 GHz, while the second path utilizes a frequency doubler to boost the frequency to around 200 GHz. After amplification, these two paths drive independent harmonic generators, which simultaneously generate the fundamental, third, and fifth harmonic of their input signals. The interleaved harmonic content is then radiated orthogonally with dual-polarized on-chip antennas. The simulated transmitted power per harmonic is approximately -25 dBm. The total DC power consumption of the chip is 1.4 W and is fabricated in a high-speed 0.13-µm SiGe-HBT technology with f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf> of 700 GHz.