Harmonic Beamforming in Time-Modulated Linear Arrays

Poli, Lorenzo; Rocca, Paolo; Oliveri, Giacomo; Massa, Andrea

doi:10.1109/tap.2011.2152323

Cited by 228 publications

(146 citation statements)

References 32 publications

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“…In the optimization process, {τ p } is perturbed in the search range [0, 1] whereas for {ε p }, the search range is defined as {1 − τ p }. Thus unlike [28], (τ p + ε p ) is always ≤ 1, and complex Fourier coefficients is obtained only by using (4). To obtain a good result in DE, the control parameters are set as -number of population (N P OP ) = 5D ('D' being the dimension of the problem), mutation constant (F ) = 0.5 and crossover constant (η c ) = 0.9.…”

Section: Optimization Using Dementioning

confidence: 99%

“…2(b), are 0 = {−20, 21.2}, 1 = {−19.96, 1.76, −6.67} and 2 = {−11.48}, respectively. Since in [28] the desired flat-top pattern is synthesized at f 0 , the method reported in [28] needs phase shifters to provide the necessary excitation phase distribution of the antenna elements.…”

Section: Optimization Using Dementioning

confidence: 99%

“…On the other hand, sideband signals can also be used in some specific applications [25][26][27][28] by controlling 'on-off' time instants of the antenna elements. For example, without using phase shifter, on-time sequences of each element are controlled to obtain an electronic beam steering technique at the first sideband of TMLAA [25].…”

Section: Introductionmentioning

confidence: 99%

“…In the first sideband, shaped patterns (flat-top and cosec 2 ) are synthesized in TMAAs with uniform static excitation amplitude and phase distributions [27]. In [28], a particle swarm (PS) based strategy is introduced for synthesizing broadside sum and difference, flat-top and sum pattern at center frequency and first sideband, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…Since, U p (t) is a time periodic function, (2) can be decomposed by applying Fourier series technique to obtain the power pattern at different harmonics of the modulation frequency, ω m = 2π/T m = 2πf m . For such an antenna array, the array factor expression at k-th harmonic is readily obtained from [25,28] as…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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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Section: Optimization Using Dementioning

confidence: 99%

Section: Optimization Using Dementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Mandal¹,

Mahanti²,

Ghatak³

2014

PIER M

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Smart Beamforming Techniques for “On Demand”WPT

Masotti

Shanawani

Costanzo

2020

Wireless Power Transmission for Sustainable Electronics

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Pattern synthesis of timed antenna array with the exploitation and suppression of harmonic radiation

Chakraborty

Ram

Mandal

2021

Int J Communication

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SummaryThe pattern synthesis of timed antenna array with the exploitation and suppression of harmonic radiation is proposed in this paper. Timed arrays are the time‐domain alternatives of conventional antenna arrays, where an additional control parameter “time” is used to generate the desired time‐averaged radiation pattern. This additional control also comes with the inherent hindrance of harmonic radiation, generally considered as an undesired effect of time modulation. In this work, this hindrance is overcome with different objectives considering the exploitation and suppression of harmonic radiation of timed arrays. To demonstrate the exploitation of harmonic radiation, a simultaneous sum and difference pattern with reduced sidelobe suitable for monopulse tracking radar systems is obtained at the fundamental and the first harmonic frequency by an optimal subarrayed pulse splitting and shifting approach. Two separate cases, considering uniform and optimized static excitations along with the proposed subarrayed pulse sequence, are presented for the exhaustive analysis of the simultaneous multibeam pattern. To address the suppression of harmonic radiation, the sidelobe level (SLL) at the fundamental frequency and the sideband levels (SBLs) of higher‐order harmonic frequencies are simultaneously reduced. In this regard, a unique pulse shifting approach for the edge elements of the array, along with an optimal set of static excitations, is proposed to enhance the efficiency of the antenna system by reducing SLL and SBLs at the same time. Two uniquely defined cost functions are chosen to address the above‐mentioned objectives by exploiting and suppressing the harmonic radiation of timed arrays, which further increases the adaptability and reconfigurability of the array. A set of 16‐element “time‐modulated” linear array (TMLA) is considered for optimization, and a wavelet mutation‐based differential evolution (DEWM) algorithm is employed to obtain the optimal solutions. Obtained numerical results are reported and also compared with previously published works to show the proposed approach's potentialities.

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Harmonic Beamforming in Time-Modulated Linear Arrays

Cited by 228 publications

References 32 publications

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

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

Smart Beamforming Techniques for “On Demand”WPT

Pattern synthesis of timed antenna array with the exploitation and suppression of harmonic radiation

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