Julio C. Bregáins

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Wireless communications are widely based on linear digital modulation methods, which introduce the digital baseband information in the amplitude and/or in the phase of a carrier sinusoid. Time-modulated arrays, on the other hand, constitute an interesting technique capable of adapting the power radiation pattern of an antenna array. In this work, we study(More)
Diversity occurs whenever several copies of the same transmitted signal arrive at a receiver. Such a situation allows for improving the performance of a wireless communication system transmitting over a radio channel without increasing the transmit power. Previous works have shown that time-modulated arrays are capable of faithfully acquiring digital(More)
One of the primary features of time-modulated arrays (TMAs) is their ability to adapt their harmonic patterns to exploit the angular diversity of multipath wireless channels. In such a case, the TMA excitations must provide an adequate level of harmonic windowing in order to safeguard both the antenna efficiency and the signal-to-noise ratio at reception.(More)
A previously developed method to place a quasi-null in a specified angular position of the near-field line source in sum patterns while, simultaneously, the far-field sidelobe level is maintained under a desired value, is shown to be applicable to linear Bayliss patterns as well. This method, as in the previous work, is performed through the use of the(More)
Time-modulated arrays (TMAs) are electromagnetic systems whose radiated power pattern is controlled by the application of variable-width periodical pulses to the individual elements. The nonlinear nature of the array operation causes the appearance of radiation patterns at the harmonic frequencies of such periodic pulses. The technique can be used for(More)
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