Main Beam Controlling Planar Antenna Array Design and Synthesis for Square Kilometre Array and Satellite Applications

摘要

Antenna arrays are currently being used for ultra sensitive radio observations in the project called Square Kilometre Array (SKA). In this paper, a planar array has been proposed to match high spatial resolution and high sensitivity requirements of the SKA, and satellite applications. The proposed design offers a well-controlled and elliptically shaped main beam. In addition, optimized thinned configuration provides minimum side lobe peaks and high directivity by applying modified binary Genetic Algorithm (GA). Design-induced modification in GA with a double-stage uniform crossover operation has been proposed. Array factor, forming the cost function with the constraint of uniform side lobe pattern, has been derived. At first, the design has been examined for side lobe peaks, side lobe pattern, and directivity in the orthogonal planes (phi = 0 and phi = pi/2). For direction-specific optimization, design offers a directivity of 32 dB and a peak side lobe level of -25 dB. A comprehensive investigation involving optimization in all the planes (phi from 0 to pi) has been carried out, giving a side lobe peak of -20 dB and a directivity of 30 dB. The achievable 3-dB beam width is 0.088, evidently fulfilling the high-resolution requirement of SKA applications. A performance comparison with several state-of-the-art synthesis methods shows that the proposed design in combination with the modified heuristic approach can provide high directivity and low beam width, well-controlled main beam, and a radiation pattern with quite competitive side lobe peaks.