Linearized Frequency Conversion Properties of Two-Port Devices as Function of the Pumping Signal Amplitude and phase

In this article a technique that allows derivation of the conversion matrix of a two-port device using a measurement setup based on a nonlinear vector network analyzer (NVNA), which is capable of identifying the optimum local oscillator (LO) level and the corresponding RF and IF terminations for a microwave mixer, is discussed and validated. This technique is applied to extract the conversion matrix of gate-pumped 0.2-lm pseudomorphic high-electron-mobility transistors (PHEMTs) driven by a 4.8-GHz signal at different power levels and using an intermediate frequency of 600 MHz. Several experimental results provide a behavioral description of the up- and down-conversion mechanism in microwave mixers and highlight the dependency of the conversion-matrix coefficients on the pumping signal amplitude and phase. Detailed validation of this technique is provided by means of a circuit-level simulation and its consistency by vector network analyzer (VNA) measurements.