Overview of selected hybrid methods in radiating system analysis

In many situations it is not sufficient to know the performance of an antenna in isolation, but instead it is necessary to know the performance characteristics of the antenna on, or in proximity to, another body or platform. Hybrid techniques which use the method of moments (MM) to treat part of the problem and some other method to account for the (usually larger) reminder are examined. In the MM/Green´s function techniques, to the usual MM matrix is added another matrix, derived typically by some other method, that accounts for the normally larger part of the problem without increasing the order of the MM matrix. These techniques utilize electric fields in their formulation and are referred to as field-based hybrid techniques. The last two hybrid techniques considered in this review paper are current-based techniques. Both use the MM for a part of the platform and use approximate current forms for the remainder of the platform. All these methods are reviewed, and their utility is illustrated by examples or by comparison to other methods