THE ACTIVE ELEMENT PATTERN

This review article will discuss the use of the active element pattern for prediction of the scan performance of large phased array antennas . The introduction and application of the concept of the active elemen t pattern goes back at least 30 years [1]-[6], but the subject is gene rally not covered in modern antenna engineering textbooks or handbooks , and many contemporary workers are unfamiliar with this simple but po werful idea. In addition, early references on this subject do not prov ide a rigorous discussion or derivation of the active element pattern, relying instead on a more qualitative interpretation. The purpose of this communication is to make the technique of active element patterns more accessible to antenna engineers, and to provide a new derivation of the basic active element pattern relations in terms of scattering parameters.