Circuit-level nonlinear/EM co-simulation and co-design of UWB receivers

The paper describes an efficient and accurate circuit-level approach to the co-design of UWB receivers integrated with broadband antennas. A full nonlinear simulation of the front end is integrated with the electromagnetically (EM)-based description of the antenna impedance and far-field performance. For each direction of incidence of the transmitted UWB pulse, a circuit description of the receiver excitation under the form of a set of Norton equivalent current sources is generated by EM theory. The source internal impedance is the antenna impedance determined by full-wave EM analysis. The receiver nonlinear analysis is carried out by a model-order reduction Harmonic Balance (HB) technique based on Krylov subspaces. The procedure allows the actual receiver sensitivity to be accurately evaluated by taking into account the amplitude and phase distortion introduced by the antenna, which may significantly change with the UWB pulse direction of incidence. It also allows an effective prediction of the link power budget, which is particularly critical in ultra-low power Impulse Radio (IR) -UWB applications.