Efficient Combination of Nonlinear and Electromagnetic CAD Techniques for the Design of Microwave Transmitters Including Integrated Antennas

This article introduces a new approach to the nonlinear/electromagnetic codesign of microwave transmitters including integrated antennas. Nonlinear analysis techniques and EM simulation are coupled to produce an accurate description of the transmitter performance. The antenna is not treated as a separate component but as an integral part of the linear subnetwork in order to fully account for any coupling effects that the circuit layout may introduce. For optimization purposes the passive circuit layout is described by neural models derived from rigorous EM simulation. A separate artificial neural network (ANN) is used in the neighborhood of each harmonic of interest in order to overcome the bandwidth problem. Special ANN are used to model the radiated field, allowing the design goals to be formulated in terms of far-field specifications, and suitable figures of merit encompassing radiation and nonlinear performance are introduced.