Nonlinear/electromagnetic co-simulation of microwave/millimeter-wave radio systems

The purpose of the presentation is to demonstrate a general and rigorous CAD procedure that can potentially provide a systematic answer to the needs of modern circuit-level microwave system simulation by combining nonlinear, electromagnetic (EM), and propagation analysis tools. First the transmitter front-end is analysed under digitally modulated IF drive as a nonlinear system with a load consisting of the antenna described by full-wave EM analysis across the frequency band of interest. In order to produce the radiated field envelope, the EM results are interfaced with an envelope-oriented harmonic-balance technique (MHB) based on Krylov-subspace model-order reduction. The far-field radiated by the antenna, possibly in the presence of inhomogeneous media, is used as the input to an advanced 3D Ray Tracing (RT)-based radio channel model, to compute the channel transfer function in realistic propagation conditions. On output, the reciprocity theorem is applied to the multiport receiving antenna under plane-wave incidence to derive a rigorous circuit description of the receiver excitation. The circuit-level nonlinear analysis of the receiver treated as a whole is again performed by MHB. Possible applications include RFID and UWB systems. The extension to multiple transmitting and receiving antennas is also possible, thus providing for the first time a system-atic approach to a full CAD-based treatment of MIMO systems