Application of time modulation in the synthesis of sum and difference patterns by using linear arrays

Fondevila, J.; Bregáins, Julio; Ares, F.; Moreno, E.

doi:10.1002/mop.21489

Cited by 93 publications

(83 citation statements)

References 5 publications

(13 reference statements)

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“…Since this is the first (to the best of the authors' knowledge) application of the time-modulation to the synthesis of monopulse sub-arrayed antenna where the sum and the difference patterns are simultaneously generated, no comparisons with other methods are possible. However, since the independent generation of difference patterns by modulating a limited number of static excitations that afford a Villeneuve sum pattern has been described in [22], similar scenarios have been considered as reference geometries. Accordingly, let us refer to a N = 30 element array with inter-element spacing d = 0.7λ [22].…”

Section: Numerical Resultsmentioning

confidence: 99%

“…For instance, difference patterns have been synthesized by time-modulating a small number of elements of a two-section array generating a sum pattern [22]. However, even though pioneering works concerned with time-modulation date back to the end of 1950s [23], the potentialities of time-modulated arrays have been only partially investigated.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of compromise sum-difference arrays through time-modulation

Rocca

Manica

Poli

et al. 2009

IET Radar Sonar Navig.

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In this paper, time-modulation is exploited for the synthesis of monopulse sub-arrayed antennas. The solution of the compromise sum-difference problem is obtained by setting the set of static excitations to an optimal sum set and synthesizing the "best compromise" difference pattern through a Continuous Partition Method (CP M ) based approach. The array elements are aggregated into sub-arrays controlled by means of RF switches with optimized "on" time-durations. The switch-on instants of the pulse sequences are then computed by means of a particle swarm optimizer to reduce the interferences caused by the sideband radiations. A selected set of numerical results is reported to assess the potentialities of time-modulation in dealing with the synthesis problem at hand.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of compromise sum-difference arrays through time-modulation

Rocca

Manica

Poli

et al. 2009

IET Radar Sonar Navig.

View full text Add to dashboard Cite

show abstract

“…Alternatively, some optimization algorithms such as the differential evolution (DE) [6,10,11,18], genetic algorithm (GA) [12] and simulated annealing (SA) [9,13] can be used to optimize the time sequences of elements.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…The major problem of the time modulated antenna arrays is that the time modulation generates unwanted harmonics or sidebands at multiples of the time modulation frequency. Many studies on the time modulated antenna arrays were concentrated on minimizing these harmonics [9][10][11][12][13]. However, sidebands do not always be harmful.…”

Section: Introductionmentioning

confidence: 99%

A Study of Am and Fm Signal Reception of Time Modulated Linear Antenna Arrays

Li¹,

Yang²,

Zhao³

et al. 2009

PIER Letters

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Abstract-The amplitude modulation (AM) and frequency modulation (FM) signal transmission of time modulated linear arrays (TMLA) is studied in this paper. The signal with a certain bandwidth received by a TMLA is time modulated by RF switches, generating many sideband signals at multiples of the time modulation frequency and each of them has the same bandwidth as the original signal. The AM and FM signals received by the TMLA were analyzed, and the requirements of the time modulation frequency for the recovery of the original signal is presented. Simulation results show that the time modulation frequency of the TMLA should be equal to or greater than the bandwidth of the original signal and a band-pass filter (BPF) has to be used to recover the original signal.

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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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Application of time modulation in the synthesis of sum and difference patterns by using linear arrays

Cited by 93 publications

References 5 publications

Synthesis of compromise sum-difference arrays through time-modulation

Synthesis of compromise sum-difference arrays through time-modulation

A Study of Am and Fm Signal Reception of Time Modulated Linear Antenna Arrays

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

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