Signal-dependent compensation in phase-shifter based arrays

It is shown that when the shape (complex envelope) of the communicated signal is known, the directivity of the phase-shifter based array and the ratio of main-lobe area to sidelobe area can be improved by utilizing a correcting function to the complex weight, based on the signal complex envelope. Because many weighted arrays already employ controllable amplitude and phase (complex weighting), the compensation can be achieved with extra software. In order to calculate the compensation, the array factor of a planar uniform phased array is expressed in terms of the complex envelope of the signal that is communicated. This is performed for a phase-shifter based array and for a true-time-delay based array. The required correction is determined by approximating the directivity of the true-time-delay based array by the directivity of the phase-shifter based array. The resulting compensation is signal- and main-direction dependent.<
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