LCMV beamforming applied to a time-modulated reflector-array: Concept and simulations

An adaptive nulling scheme for a time-modulated reflector-array (TMRA) based on linearly constrained minimum variance (LCMV) beamforming is introduced and investigated. Compared to conventional phased arrays or reflector arrays, a TMRA is potentially simpler to implement in hardware as it does not require a complex feed structure or the use of phase shifters. Linearly constrained minimum variance algorithm is used in various applications of array signal processing and in this contribution we apply the scheme to a TMRA. A simple example of 8 element linear TMRA is analysed using Fourier series and array-factor theory. The switching sequence applied to the TMRA is derived from a LCMV algorithm to produce a prescribed scattering pattern at harmonic frequencies. The performance of a theoretical TMRA model consisting of switchable elements is compared to that of a conventional phased array with phase shifters. A TMRA based on bowtie dipole design were constructed and simulated using full-wave simulator to show adaptive nulling at harmonic frequencies.