A 340 GHz MMIC 4× sub-harmonic mixer using silicon-based Schottky barrier diodes

The terahertz 4 × sub-harmonic down-mixer fabricated in standard 0.13μm SiGe BiCMOS Schottky barrier diodes is demonstrated. The 340 GHz sub-harmonic mixer (SHM) is designed based on anti-parallel-diode-pair (APDP). With the 4th harmonic, LO frequency of 85 GHz is used to pump the 340GHz SHM. With LO power of 9dBm, the mixer exhibits measured conversion loss of 39-43dB in the lower band (320-340 GHz) and 40-48dB in the upper band (340-360 GHz). The measured input 1dB conversion gain compression point is -10dBm at RF frequency of 325 GHz. LO-IF isolation is measured to be 32dB at 85 GHz. The chip occupies 550μm× 610μm including the testing pads.