ALGORITHM FOR GENERATING AN EXTENDED DIRECTIVITY PATTERN OF A PHASED ARRAY ANTENNA

Abstract

An analysis of existing methods for synthesizing antennas according to a given radiation
pattern, in which the generated radiation pattern is the sum of partial rays, is carried out. It has
been established that in these methods an iterative process is organized, at each step of which a
new additional beam is added to the already formed beam. In this case, search optimization algorithms
are used to determine the parameters of the additional beam. The existence of these methods
allows us to separately consider algorithms for determining the parameters of additional rays
at each step of the iterative process, as processes for solving independent problems. A variation of
such a problem is the search for parameters of additional rays to form a one-dimensionally extended
radiation pattern. An analytical algorithm for the formation of a one-dimensionally expanded
beam of a linear antenna is proposed and justified, represented as a sum of three narrower
partial beams after determining two unknown parameters: the angle of separation of additional
beams and the complex amplitude of these beams. Relationships have been obtained that make it
possible to reduce the problem of forming an extended beam of a linear antenna to the problem of
optimizing the expression for one parameter - the angle of separation of additional beams relative
to the central one. It is shown that the second required parameter, the complex amplitude of the
additional beam, is determined analytically. It was established that the choice of the required parameters
of the optimization problem should be based on the requirements for maximizing the
directional coefficient. After solving the optimization problem, the amplitude-phase distribution in
the aperture of a linear antenna is represented as a superposition of three amplitude-phase distributions
to form the corresponding partial rays. It is shown that the algorithm has limitations associated
with the expansion of rays, since the feasibility of the requirements is related to the width of
the used partial rays. In this regard, it is indicated that the proposed algorithm should be considered
as an integral part of an iterative process, at each step of which additional beam expansion
occurs. The results of the implementation of the proposed algorithm when forming several extended
beams are presented, which confirm the performance of the proposed algorithm.