A Full Large Signal Analysis of Active Microwave Mixers

A new approach is used for the analysis of active microwave mixers which combine mixing and amplification, e.g. mixers based on single and dual-gate FETs (DGFETs). The normally used assumption that the LO signal alone is large while all the other signals present can be considered small is no longer valid when amplification is combined with the mixing process using a device with non-linear characteristics like a DGFET. In this case all the signals at all the device ports should be assumed large. A new algorithm, based on the modified harmonic balance (MHB) technique is developed and applied to the simulation of a mixer based on a Raytheon RDX832 DGFET for which device data was available. The simulation results are compared with the experimentally obtained mixer performance results of gain vs LO power and gain vs RF input power and show good agreement.