Synthesizing Asymmetric Side Lobe Pattern with Steered Nulling in Nonuniformly Excited Linear Arrays by Controlling Edge Elements

Abstract

In radar antennas, asymmetric side lobes are useful, where undesired signals such as noise and ground clutter should be minimized. Also, for practical implementation, the feeding network of such antennas should be efficiently designed. In this paper, a simple analytical method for synthesizing asymmetric side lobe pattern with a wide-angle steered null in the nonuniformly excited linear arrays is presented. In this method, the difference in the side lobe levels on both sides of the main beam is achieved by varying just the phase excitations of the two-edge elements. The major novelty of this paper lies in the fact that the required asymmetric side lobe pattern can be achieved by changing a single phase shifter resulting in a simple feeding network.

Planar Array with Optimized Perimeter Elements

“…By comparing (1) and 2, it is clear that the number of the adjustable weights, w nm , has been reduced from N × M in the fully adaptive planar array to only 2( − 1) + 2( − 1)in the proposed planar array. Unlike the control methods of the two edge elements that were presented in [1], [3], [4], [10] and [11], the proposed planar array has enough degrees of freedom to efficiently accomplish low SLL and null controls as will be shown in the simulation results. The optimization problem is formulated as the determination of the complex weights of the perimeter elements such that the resulting radiation pattern is constrained by one or more of the following:…”

“…One effect of high sidelobes is the inability to detect the targets due to the strong ground clutter and/or high interference environment. In order to suppress these clutter echoes, the array pattern should be designed with low sidelobes or asymmetric sidelobes [1], [2]. However, an increase in the width of the mainlobe is unavoidable as the cost of obtaining low sidelobes.…”

Introductory Chapter: Introduction to Array Pattern Optimization

“…Other approaches have utilized few elements at the center of the array to achieve better adaptive responses [16]. The side element idea was also deployed for the synthesis of asymmetrical radiation pattern where it is desirable to highly reduce the sidelobe on one side of the main beam while tolerating a higher sidelobes on the other side [17].…”

A Method for Thinning Useless Elements in the Planar Antenna Arrays

“…As an example, consider a large planar array with 40 × 40 elements, where there are 2 1600 possible searching combinations. Thus, simpler techniques with smaller or restricted searching spaces are currently of great research importance in practice [11][12][13][14][15][16].…”