Modeling and Identification of Ultra-Wideband Analog Multipliers

Analog multipliers are employed in many applications. In conventional RF front ends, for example, they are widely used for frequency conversion tasks. In noncoherent energy detectors or autocorrelation receivers, they multiply the (broadband) input signal by itself to achieve a down-conversion. Unfortunately, there exist no ideal hardware realizations of such devices, hence multipliers inevitably create undesired signal content at their output. To be able to deal with these effects or correct for them, we need to be able to model and identify realistic RF multipliers. This paper proposes and validates a multiple-input single-output Wiener-Hammerstein model for ultra-wideband (UWB) analog multipliers. The structure of the proposed model gives insight in the distortions created. It thus provides the possibility to study the realistic behavior of systems involving those multipliers, e.g., the influence of undesired nonlinear signal content onto noncoherent UWB receivers. A comparison of the model performance is shown with respect to measurements and circuit simulations.