Pattern synthesis in time-modulated linear arrays through pulse shifting

Poli, Lorenzo; Rocca, Paolo; Manica, Luca; Massa, Andrea

doi:10.1049/iet-map.2009.0042

Cited by 173 publications

(124 citation statements)

References 14 publications

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“…A differential evolution algorithm is introduced in [10], for radiation pattern optimization. Works like [11] have applied pulse shifting techniques for synthesizing the radiation pattern. A study on FMCW chirps in time modulated arrays has been elaborated in [12].…”

Section: Introductionmentioning

confidence: 99%

Random phase center motion technique for enhanced angle-Doppler discrimination using MIMO radars

Hammes¹,

Shankar

Nijsure

et al. 2017

2017 25th European Signal Processing Conference (EUSIPCO)

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Abstract-A random Phase Center Motion (PCM) technique is presented in this paper, based on Frequency Modulated Continuous Wave (FMCW) radar, in order to suppress the angleDoppler coupling in Time Division Multiplex (TDM) MultipleInput-Multiple-Output (MIMO) radar when employing sparse array structures. The presented approach exploits an apparently moving transmit platform or PCM due to spatio-temporal transmit array modulation. In particular, the work considers a framework utilizing a random PCM trajectory. The statistical characterization of the random PCM trajectory is devised, such that the PCM and the target motion coupling is minimal, while the angular resolution is increased by enabling the virtual MIMO concept. In more details, this paper discusses sidelobe suppression approaches within the angle-Doppler Ambiguity Function (AF) by introducing a phase center probability density function within the array. This allows for enhanced discrimination of multiple targets. Simulation results demonstrate the suppression angleDoppler coupling by more than 30 dB, even though spatiotemporal transmit array modulation is done across chirps which leads usually to strong angle-Doppler coupling.

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Section: Introductionmentioning

confidence: 99%

Random phase center motion technique for enhanced angle-Doppler discrimination using MIMO radars

Hammes¹,

Shankar

Nijsure

et al. 2017

2017 25th European Signal Processing Conference (EUSIPCO)

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“…However, inherent sideband radiations in TMAA reduces antenna efficiency and directivity [15,16] when the desired pattern is synthesized at the operating frequency only. Accordingly, during the last decade, a number of contributions with different time-modulation approaches based on different optimization tools have been successfully applied to realize different patterns at the operating frequency by suppressing SBLs to sufficiently low values [10][11][12][13][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Simultaneous Multiple-Harmonic-Patterns in Time-Modulated Linear Antenna Arrays

Mandal¹,

Mahanti²,

Ghatak³

2014

PIER M

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Abstract-In time-modulated antenna arrays (TMAAs), as a result of periodical switch-on and switchoff of the antenna elements, including operating frequency (termed as center frequency) signal, sideband signals are appeared at either sides of the center frequency in integer multiples of the modulation frequency. In this paper, it is shown that without using phase shifters, just by suitably controlling the on-time instants (OTIs) and on-time durations (OTDs) of a time-modulated linear antenna array (TMLAA) elements, simultaneously, along with a pencil beam pattern at the operating frequency, a shaped beam pattern can be obtained at both the first positive and negative harmonics of the timemodulation frequency. The important advantage of such a technique is that realization of multi-beam pattern in conventional antenna array (CAA) system generally requires complex feed network, whereas by using simple radio frequency (RF) switching circuit in the feed network of TMLAA, by virtue of the properties of harmonic radiations, synthesis of a shaped pattern at either (positive or negative) harmonic results in generating the same pattern in its opposite harmonic, and the synthesized patterns at different harmonics can be simultaneously used as independent communication channels. By employing a differential evolution (DE) based optimization method, numerical results for a 16-element TMLAA with uniform excitation show that in conjunction with a pencil beam pattern at the center frequency, a flat-top or a cosec square pattern at first positive and negative sidebands of side-lobe levels (SLL) −20 dB can be synthesized by suppressing the higher sideband level (SBL) to below −10 dB.

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“…Toward this end, many techniques have been proposed based on differential evolution (DE) [4][5][6][7], simulated annealing (SA) [8], and particle swarm optimizer (P SO) [9][10][11] aimed at minimizing the sideband level (SBL) [4], namely the peak level of the harmonic patterns, or the overall harmonic content [9] or both [11] by suitably defining the timepulse durations. The possibility to modify the periodic waveforms has been also examined in [12][13][14][15] to achieve a better handling of the SRs. More specifically, a simple time-shift between the pulses has been exploited in [12] to control the harmonic patterns, while in [14] splitting rectangular pulses in multiple sub-pulses has been proposed to set the distribution of the sideband power of the harmonic frequencies.…”

Section: Introductionmentioning

confidence: 99%

“…The possibility to modify the periodic waveforms has been also examined in [12][13][14][15] to achieve a better handling of the SRs. More specifically, a simple time-shift between the pulses has been exploited in [12] to control the harmonic patterns, while in [14] splitting rectangular pulses in multiple sub-pulses has been proposed to set the distribution of the sideband power of the harmonic frequencies. Moreover, the use of alternative waveforms (e.g., trapezoidal and raised-cosine) in [15] provided a reduction of the radiated harmonic content.…”

Section: Introductionmentioning

confidence: 99%

An Iterative Approach for the Synthesis of Optimized Sparse Time-Modulated Linear Arrays

Rocca¹,

D’Urso²,

Poli³

2013

PIER B

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Abstract-In this paper, the synthesis of sparse time-modulated linear arrays with minimum number of elements and controlled harmonic radiations is investigated. The proposed iterative approach based on a particle swarm optimization is aimed at finding the array configuration with the minimum number of elements and the optimal pulse sequence that affords a beam pattern with the same features of a reference one also limiting the amount of sideband radiations under a specific threshold. A set of representative numerical examples is discussed to assess the effectiveness and the reliability of the proposed approach.

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Pattern synthesis in time-modulated linear arrays through pulse shifting

Cited by 173 publications

References 14 publications

Random phase center motion technique for enhanced angle-Doppler discrimination using MIMO radars

Random phase center motion technique for enhanced angle-Doppler discrimination using MIMO radars

Synthesis of Simultaneous Multiple-Harmonic-Patterns in Time-Modulated Linear Antenna Arrays

An Iterative Approach for the Synthesis of Optimized Sparse Time-Modulated Linear Arrays

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