Iterative Approach for the Nonlinear Simulation of Active Antennas

In active transmitting arrays, high-power amplifiers (HPA) are conveniently used to provide microwave power at the input of each radiating element. They are generally connected to the radiating elements through isolators, designed to reduce the influence of the surroundings on the amplifiers load. Load-pull effects may indeed affect the transfer characteristics of HPAs and even destroy them above excessive Voltage Standing Wave Ratios (VSWRs). Still, isolators are generally bulky and lossy devices, and advantages could be obtained by downsizing these stages. In the perspective of reducing isolation, the impact of load variations must be predicted for a safe design of array antennas. In this paper, an original iterative approach is proposed for the simulation of transmitting arrays, supplied by HPAs driven into distorsion, taking into account varying antenna loads induced by coupling effects (see Fig. 1). The global description of the array antenna is achieved in the frequency domain through a Domain Decomposition Method (DDM). It allows to describe circuit components and antenna components altogether in highly modular schemes.