Enhanced Time-Modulated Arrays for Harmonic Beamforming

Maneiro-Catoira, Roberto; Bregáins, Julio; García-Naya, José A.; Castedo, Luis

doi:10.1109/jstsp.2016.2627178

Cited by 55 publications

(37 citation statements)

References 16 publications

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“…The beam radiation on the fundamental harmonic component with about -13 dB SLL has been obtained. When the rectangular pulses and trapezoidal pulses with normalized rise/fall times of As another approach for harmonic beamforming, the sum of weighted cosine (SWC) pulses has been proposed to flexibly window the harmonics in [23]. With the help of the SWC pulse coefficients, the SLL of the main, first, and second harmonic radiation is -35 dB, -22 dB, and -27 dB, respectively.…”

Section: Performance Comparison With the State-of-the-art Studies In mentioning

confidence: 99%

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A multibeam subarrayed time-modulated linear array

Yeşilyurt¹,

Kanbaz²,

Aksoy³

2020

Turk J Elec Eng & Comp Sci

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

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Section: Performance Comparison With the State-of-the-art Studies In mentioning

confidence: 99%

“…The C mn expression can be written as the sum of I , I 1 , and I 2 and is given by . (23) With the help of the udv = uv − vdu integral transformation formula, the integral in the I 1 and I 2 expressions can be written as:…”

Section: Appendixmentioning

confidence: 99%

A multibeam subarrayed time-modulated linear array

Yeşilyurt¹,

Kanbaz²,

Aksoy³

2020

Turk J Elec Eng & Comp Sci

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“…Such vulnerabilities are directly related to the frequency response of rectangular pulses (Chapter 3, p89, [78]): a minimum main-lobe width and a modest side-lobe level (−13 dB), together with a slow (first order) asymptotic side-lobe decay. In fact, taking as the starting point the weaknesses of rectangular pulses when applied to harmonic beamforming, the following two contributions were introduced in [79]: A type of pulses that are more suitable for harmonic beamforming with TMA: the so-called sum-of-weighted-cosine (SWC) pulses [80]. …”

Section: State Of the Artmentioning

confidence: 99%

“…A common denominator of these recent investigations [72,75,77,79] is that TMA are analyzed and evaluated not only from an antenna outlook, but also from a signal processing perspective.…”

Section: State Of the Artmentioning

confidence: 99%

Time Modulated Arrays: From their Origin to Their Utilization in Wireless Communication Systems

Maneiro-Catoira

Bregáins

García-Naya

et al. 2017

Sensors

Self Cite

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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 improving the side-lobe level (SLL) topology of the radiation pattern at the central frequency and/or to profitably exploit the harmonic patterns in order to supply smart antenna capabilities. Among the latter features, the TMA harmonic beamforming takes on special importance due to its attractive trade-off performance-hardware complexity. From this perspective, TMAs are sensors capable of transforming the spatial diversity of a communication channel into frequency diversity, thus improving the performance of a wireless communication. In addition to a walk through the origins of the concept, and a brief analysis of the mathematical fundamentals, this paper organizes the prolific state of the art of TMAs in two major thematic blocks: (1) TMA design from an antenna perspective; and (2) TMA design from a signal processing perspective.

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“…Thus, the array elements are not fully utilized. Differently, a time-modulated array excitation with periodic sum-of-weighted-cosine pulses has been proposed in [14]. However, the energy of the transmitted signal is reduced due to the amplitude weighting.…”

Section: Introductionmentioning

confidence: 99%

Beamforming of Frequency Diverse Array Radar With Nonlinear Frequency Offset Based on Logistic Map

Wang¹,

Mu²,

Song³

et al. 2018

PIER M

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In this paper, a multi-carrier nonlinear frequency modulation system based on pseudorandom frequency offset is designed. The reduction of the main lobe 3 dB width and the side-lobe peaks cannot be realized simultaneously in conventional beamforming schemes, especially when the number of array elements remains unchanged. The proposed system can reduce the main-lobe 3 dB width and suppressing the side-lobe peaks simultaneously. This is done by adjusting the number of sub-signals, frequency offset coefficient and the inter-element spacing. Then, through time slot processing, signal power is focused on different targets. Numerical simulation experiments are implemented to validate the theoretical analysis of the proposed methodology, and comparisons with other techniques are made.

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Enhanced Time-Modulated Arrays for Harmonic Beamforming

Cited by 55 publications

References 16 publications

A multibeam subarrayed time-modulated linear array

A multibeam subarrayed time-modulated linear array

Time Modulated Arrays: From their Origin to Their Utilization in Wireless Communication Systems

Beamforming of Frequency Diverse Array Radar With Nonlinear Frequency Offset Based on Logistic Map

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