MVDR beamforming applied to a time-modulated reflector-array

An adaptive nulling scheme for a time-modulated reflector-array (TMRA) based on Minimum Variance Distortionless Response (MVDR) beamforming is introduced and investigated. Compared to conventional phased arrays or reflector arrays, a TMRA is potentially simpler to apply in hardware as it does not require a complex feed network or the use of phase shifters. Minimum variance distortionless response 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 MVDR 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.