A multibeam subarrayed time-modulated linear array

Abstract

In conventional time-modulated arrays (TMAs), because of the usage of the RF-switch, harmonics aregenerated at multiples of the modulation frequency. In this study, the synthesis of time-modulated arrays has beenanalyzed for cognitive radio (CR) systems, in which these harmonics are suitably exploited for more efficient utilizationof the spectrum. In order to accomplish the desired pattern at requested harmonic frequencies, a new excitation strategywith sinusoidal signals is proposed. The use of sinusoidal waveforms creates independent beams, allowing independentsteering capability. Moreover, by utilizing the subarray structure, it is possible to have a smaller number of excitationfunctions in the hardware. It is shown by means of explanatory examples that the effectiveness of the proposed approachis due to free-adjustable beamforming, beam steering, and low complexity.