Power calibration methods for frequency extenders aided modulated measurements at sub-THz/THz

6G technologies are aiming at large absolute bandwidth available at sub-THz/THz frequency ranges for ultrahigh speed wireless communication. State-Of-the-art measurement instruments are aided by the frequency extenders to facilitate the extensive on-chip RF characterization of the radio frequency integrated circuits. Unlike millimeter wave measurements, sub-THz/THz on-chip measurements involve the cascaded connections of several RF laboratory components. This requires extensive characterization of the measurement setup to de-embed the effect of the measurement setup from the actual measurement of the device under test. This work highlights the challenge associated with power calibration of the measurement setup for the modulated signal measurement at sub-THz/THz frequency range. Additionally, methods to measure absolute power level and estimate the local oscillator (LO) leakage from frequency upconverter are discussed.