Advanced Pulse Sequence Design in Time-Modulated Arrays for Cognitive Radio

Poli, Lorenzo; Rocca, Paolo; Oliveri, Giacomo; Chuan, Men; Mazzucco, Christian; Verzura, Stefano; Lombardi, Renato; Massa, Andrea

doi:10.1109/lawp.2018.2821715

Cited by 32 publications

(9 citation statements)

References 22 publications

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“…Furthermore, the application of TMA is extended toward radio astronomy and space application 37 . It applies in secure communication, 38 multiple‐input‐multiple‐output antenna design for smart communication and cognitive radio application, 39,40 direct broadcast satellite, and personal communication satellite 41 . A different perspective on the utilization of TMAs is that power loss due to the harmonics radiation due to periodic switch can be considered as a source of diversity to be exploited for advanced antenna applications.…”

Section: Introductionmentioning

confidence: 99%

Multi‐beam steered harmonic pattern synthesis in timed antenna array with optimized and pre‐defined RF switching

Ram

2021

Int J Numerical Modelling

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Optimal harmonic beam steering of the time‐modulated linear antenna array (TMLAA) with optimized and pre‐defined ON and OFF switching schemes are proposed in this work. Three different approaches are considered to obtain various beam steering behaviors of TMLAA. The first approach is considered for the optimization of ON–OFF switching sequence for the steering of the harmonic beams toward approximately ±30° along with the simultaneous reduction of side lobe level (SLL) and side band level (SBL). Second approach is considered for the optimization of ON–OFF switching sequence for the steering of the harmonic beams toward approximately ±30° and ±60° simultaneously. Third approach is considered for the optimal reduction of SLL and SBL of harmonically steered beams for a pre‐defined ON–OFF switching scheme. Two unique cost function is proposed in this work to achieve the optimal parameter for above mentioned three different approaches. The first cost function is used for the optimization of Ton and Toff switching sequence and antenna element spacing of the array. These optimal values will lead to steer the main beam of first positive and negative harmonic radiation from the main beam of the fundamental radiation pattern and reduce SLL and SBL simultaneously. Second cost function deals with the optimization of excitation amplitude and distance between any two consecutive antennas of the array. These optimal values lead to reducing the SLL and SBL simultaneously harmonically steered beam obtained by pre‐defined Ton and Toff switching sequence. Optimization algorithm applied to get the optimal value of the variable parameters is Novel Particle Swarm Optimization. Further to explain the stated proposed approach, four different sets of 10‐, 16‐, 20‐, 32‐element TMLAA are taken as an example. Some of the simulation results are validated through electromagnetic simulator to validate the result obtained by MATLAB.

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Section: Introductionmentioning

confidence: 99%

Multi‐beam steered harmonic pattern synthesis in timed antenna array with optimized and pre‐defined RF switching

Ram

2021

Int J Numerical Modelling

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“…A switch has only two state of ON and OFF, so in order to form trapezoidal pulse in reality, each element can be equipped with a radio frequency (RF) variable gain amplifier (VGA). e periodic trapezoidal pulse of period T n governs the digitally controlled VGA instead of RF switches to transmit signal [24]. Compared with conventional timemodulated array based on RF switches, the power consumption is acceptable and the complexity of hardware structure is approximate [25].…”

Section: Trapezoidal Pulse Time-modulated Switching Functionmentioning

confidence: 99%

Pattern Synthesis of Time-Modulated Sparse Array by an OPM-CVX Algorithm

Liang

Jiang

Liu

et al. 2020

Mathematical Problems in Engineering

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This paper addresses the constrained multiobjective optimization problem of time-modulated sparse arrays. The synthesis objective is to find an optimal element arrangement and associated excitation strategy of sparse arrays, which realize the balance of radiation power and sideband suppression performance with minimum number of elements, and suppress side lobe level simultaneously. A novel hybrid algorithm based on orthogonal perturbation method and convex optimization (OPM-CVX) for the synthesis of time-modulated sparse antenna array is presented in this paper. In order to satisfy the main lobe beamforming and side lobe suppression of sparse arrays, the proposed method optimizes element positions with minimum array numbers by orthogonal perturbation method and optimizes excitations of array element with dynamic range ratio constraint by convex optimization. Furthermore, a trapezoidal pulse time-modulated switching function is proposed to find the balance of radiation power and sideband suppression performance. The numerical results indicate that the proposed algorithm can be an effective approach for synthesis problems of time-modulated sparse arrays.

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“…A possible solution for electronic beam steering has been proposed with an adjustable pulse sequence, which also simplified the array beamforming network (BFN) by avoiding the use of phase shifters 14 . The use of TMAs with the exploitation of SRs has found application in several cutting‐edge scenarios such as cognitive radio systems, 15,16 multichannel MIMO radars, 17 secure wireless communication, 18 and so forth.…”

Section: Introductionmentioning

confidence: 99%

Multibeam steered pattern synthesis in time‐modulated antenna array with controlled harmonic radiation

Chakraborty

Ram

Mandal

2021

Int J RF Microw Comput Aided Eng

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This article deals with the synthesis of multibeam steerable patterns in time‐modulated arrays (TMAs) for electronic scanning. The simultaneous generation of multiple beams in TMAs can be achieved through the exploitation of undesired harmonic radiations emitted at the multiples of modulating frequency due to the periodic switching. The direction‐dependent harmonic beams are capable of producing independent information channels with different spatial distributions beneficial for electronic beam steering. Multibeam patterns associated with harmonic frequencies along with the fundamental pattern can be synthesized with suitably designed switching schemes. The potentialities of linear TMAs are explored in this article to generate a simultaneous sum and difference pattern useful for monopulse tracking systems. Further assessment of multipattern operations with linear TMAs are proposed with beam steering at lower‐order harmonics. Steered double sum pattern with controlled harmonic radiations are also generated to achieve a steered multibeam with simplified beamforming network. Towards this aim, both the analytical and the optimized solutions of periodic switching sequences for different multibeam patterns are developed. Modified differential evolution with a wavelet‐based mutation strategy (DEWM) is employed for the optimal solution. Representative results are assessed and compared with other published literature results to show the effectiveness of the proposed methods.

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Advanced Pulse Sequence Design in Time-Modulated Arrays for Cognitive Radio

Cited by 32 publications

References 22 publications

Multi‐beam steered harmonic pattern synthesis in timed antenna array with optimized and pre‐defined RF switching

Multi‐beam steered harmonic pattern synthesis in timed antenna array with optimized and pre‐defined RF switching

Pattern Synthesis of Time-Modulated Sparse Array by an OPM-CVX Algorithm

Multibeam steered pattern synthesis in time‐modulated antenna array with controlled harmonic radiation

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