V.A. Voloshin, A.Yu. Larin, O.V. Ovodov
For plane active phased antenna array (APAA) with rectangular structure of a radiating element arrangement the synthesis algorithm of the amplitude-phase distribution is developed for the given angle of joint scanning two directional diagrams of the complicated form - cosecant and compensating diagrams. Work of algorithm is illustrated by numerical examples for APAA with elliptic boundary form of an aperture.
Method of the partial pensil-beam diagrams, formed by a full elliptic antenna aperture, allows to synthesize cosecant diagram and compensating diagram with zero in the cosecant section direction with enough high accuracy. The problem of searching of partial diagram complex amplitude reduced to a solution of the overdetermined systems of the linear algebraic equations (SLАE). It is fulfilled with use of the iterative conjugate gradients method ensuring high enough accuracy of synthesis of the given directional patterns.
Synthesis is carried out in local system of coordinates, in which the axis passes through the given direction ( ) of the cosecant diagram maximum. Calculation of some partial diagrams is carried out in a plane which are passing through an axis and vertical axis OY. It is necessary for correct orientation cosecant diagram concerning of the ground plane.
In wide sector of scan angles the maximal deflection of the synthesized cosecant form from given form does not exceed 6 % at levels below 0.5 from a maximum. Thus the cosecant section width makes 30 degrees. For the majority of synthesis versions it is enough to use of eight partial pensil-beam diagram.
Numerical check of joint scanning cosecant and compensating diagrams is executed on the example 3240-element APAA in a wide range of scan angles