Asymptotic Feature of an Adaptive Array and Its Application to Array Pattern Synthesis

Masaharu FUJITA
Kazuaki TAKAO

IEICE TRANSACTIONS (1976-1990)   Vol.E61    No.8    pp.599-603
Publication Date: 1978/08/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Antenna and Propagation

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A symptotic equivalency between the adaptive array under directional constraint and the synthesized array with maximum directive gain subject to null constraint is proved analytically. (The analytical expression of the solution of the latter which has only been treated numerically is derived here.) Method of analysis is based on the orthogonal projection of a vector in the multidimensional space with properly chosen base. The results of adaptive and conventional methods are given in closed forms and their proportional relationship is shown obviously. Based on the characteristics of the adaptive array which gives the maximum output signal-to-noise ratio, its application to the pattern synthesis problem is investigated for the environment of various combinations of the interference and internal noise. Special emphasis is laid upon the case of super-gain phenomenon, where the angular separation between the desired signal and interference is very close. Even in this case, the adaptive technique does not require any introduction of additional parameters like Q-factor, but guarantees the optimum solution by virtue of its guiding principle. It is also shown that the adaptive technique always gives higher output signal-to-noise ratio than the conventional synthesis method. Some numerical examples are presented to prove the discussions clearly.