High-dynamic-range measurement of millimeter-wave amplifier using 140-GHz fundamental mixer

Analysis and measurement of radio signals above 60 GHz requires connection of an external mixer to a commercial spectrum analyzer. In this setup, in addition to the actual frequency components, unwanted multiple response generated by the external mixer are also observed simultaneously, making it difficult to observe the actual frequency components. Furthermore, the signal components are easily buried by measuring instrument noise due to the poor mixer conversion efficiency, causing difficulties in observing very low power signals. This paper presents the results of some tests and trials of a 140-GHz fundamental mixing test system with potential for high-dynamic range measurements and small unwanted multiple response compared to measurements using previous harmonic mixers. The results are the first to demonstrate a 20-dB or higher dynamic range as well as excellent wideband suppression of multiple response compared to measurements using harmonic mixers.