A THz Fourth-harmonic Conversion System Expanding Microwave to THz Band

•An SBD-based THz fourth-harmonic conversion system is designed and fabricated.•The C-band IF and Ku-band LO signals are up-converted to RF signal of 364–380 GHz.•This system has lower LO frequency or CL comparing with commercial mixers.•It’s a scheme to generate lower frequency THz signal based on microwave generators.