Design of a Low Sidelobe Time Modulated Linear Array With Uniform Amplitude and Sub-Sectional Optimized Time Steps

Abstract

A novel approach for the design of low sidelobe time modulated linear arrays (TMLAs) with uniform amplitude excitations and suppressed sidebands is presented. The approach is based on the division of the time modulation period <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Tp</i> into several time steps with variable lengths. In each time step, the switch-on and switch-off times are optimized via the differential evolution (DE) algorithm. As compared to previous approaches, such as the variable aperture sizes (VAS), pulse shifting, and binary optimized time sequences (BOTS), the proposed approach has more flexibility in the design of time sequences in TMLAs. Numerical results show that a -30 dB sidelobe pattern with uniform excitations can be synthesized, while the sideband level (SBL) is suppressed to -27.8 dB. Experimental results based on a 16-element printed dipole linear array agree with the theoretical results, thus verified the proposed approach.