Beamforming Optimization for Time-Modulated Circular-Aperture Grid Array With DE Algorithm

• Published in: IEEE antennas and wireless propagation letters Vol. 17; no. 12; pp. 2434 - 2438
• Main Authors: Jiang, Zhong Jin, Zhao, Shumin, Chen, Yangyang, Cui, Tie Jun
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Amplitude modulation; Amplitudes; Antenna arrays; Apertures; Arrays; Beamforming; Beamforming optimization; circular-aperture grid array; Circularity; differential evolution (DE) algorithm; Dynamic range; Evolutionary algorithms; Heuristic algorithms; Manganese; Modulation; Optimization; Sidebands; Sidelobes; time modulation; Weight; Weighting
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2018.2877470

This letter put forward a method of numerical optimization for the circular-aperture time-modulated grid array. The amplitude weight and the time modulation pulsewidth are optimized based on a differential evolution algorithm to get the needed array pattern. Adopting the weighting mode of the conventional rectangular array, the equivalent weighting of a circular-aperture time-modulated array is decomposed into two independent components, respectively, in the horizontal and vertical directions, so as to shorten the length of the optimization vector from M × N order to M + N order. Besides, the circular-aperture time-modulated array is symmetrically excited in the horizontal and vertical directions. The numerical experiments show that the differential evolution algorithm can realize a sidelobe level of −35 dB and a nulling level of −60 dB in the patterns of the center frequency and one chosen sideband, and the unexploited sidebands are also suppressed with their peak levels lower than −35 dB. Meanwhile, the dynamic range of the amplitude weighting and the time modulation pulsewidth can be limited to 10 dB. The overall efficiency of the time-modulated array is 0.28.