Analysis of Nonlinearly Loaded Multiport Antenna Structures Over an Imperfect Ground Plane Using the Volterra-Series Method

Volterra-series analysis is applied to nonlinearly loaded antennas over an imperfect ground plane. The nature of the imperfect ground can be taken into account either exactly by the Sommerfeld formulation or approximately by the reflection-coefficient method. After the electromagnetic-field problem is reduced to a network problem by application of the method of moments, the distributed nonlinear loads are approximated by lumped loads. The nonlinear network problem is then solved using the Volterra technique. A procedure for obtaining a time-domain solution from the frequencydomain solution without using the fast Fourier transform technique is demonstrated.