An Overview on Time/Frequency Modulated Array Processing

Wang, Wen-Qin; So, Hing Cheung; Farina, A.

doi:10.1109/jstsp.2016.2627182

Cited by 197 publications

(65 citation statements)

References 148 publications

(140 reference statements)

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“…TMA is a technique wherein by introducing a fourth dimension, time, as an additional degree of freedom for the array design, i.e., connecting and disconnecting the antenna elements from the feeding network in time domain, the radiation pattern can be further manipulated [14]. The approach has been primarily exploited for array radiation pattern synthesis with suppressed sidelobes by shifting the signal energy projected along sidelobe directions out of the system operating frequency bands [15], [16]. Until recently, this ability of shifting the frequency of radiated signals has been found useful for a number of applications, such as direction finding [17] and space division multiple access [18].…”

Section: Introductionmentioning

confidence: 99%

Time-Modulated OFDM Directional Modulation Transmitters

Ding

Fusco

Zhang

et al. 2019

IEEE Trans. Veh. Technol.

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In this paper directional modulation (DM) transmitters, designed for orthogonal frequency-division multiplexing (OFDM) wireless data transfer are proposed using time-modulated arrays (TMAs). It is shown that by properly designing the switch controlling time sequences the proposed time-modulated OFDM DM systems exhibit promising features, such as i) requires only one radio frequency (RF) chain, ii) the conventional efficient OFDM signal construction approach, i.e., by using inverse fast Fourier transform (IFFT) modules, can be adopted, iii) it is 'DM synthesisfree', meaning that there is no need to re-synthesize the array excitation vectors for different secure communication directions, different modulation schemes, and different DM power efficiencies; and iv) the trade-off between secrecy performance and power efficiency can be flexibly adjusted. Index Terms-Directional Modulation (DM), orthogonal frequencydivision multiplexing (OFDM), physical-layer wireless security, timemodulated array (TMA) Readers who are following DM developments may be aware of a number of recent DM works, which claim that the FDA concept (and its variants such as non-linear frequency increments and random subcarrier selections) can be incorporated into DM transmitters, achieving free-space wireless security in range-domain, e.g. the random-subcarrier-selection-based OFDM DM transmitters in [19] and some of the references wherein. However, in those works one important factor was overlooked, which is that 'FDA range-angle dependent beamforming patterns are also functions of time'. This

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Section: Introductionmentioning

confidence: 99%

Time-Modulated OFDM Directional Modulation Transmitters

Ding

Fusco

Zhang

et al. 2019

IEEE Trans. Veh. Technol.

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“…Because of its wide application prospects, FDA has attracted extensive attention in recent years [15][16][17][18]. A technology for FDA antenna systems that could generate anglerange-dependent beamforming is put forward in [19].…”

Section: Introductionmentioning

confidence: 99%

Stepped Frequency Pulse Frequency Diverse Array Radar for Target Localization in Angle and Range Domains

Tan

Wang

et al. 2018

International Journal of Antennas and Propagation

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Unlike phased array bringing angle-dependent and range-independent beamforming, a new kind of radar system called frequency diverse array (FDA) has been widely used for its ability to generate angle-range-dependent beampattern, which provides a broad prospect of radar application. Nevertheless, FDA beampattern is coupling in the angle and range responses, which results in the difficulty for FDA to differentiate the target in two domains simultaneously. In this paper, a stepped frequency pulse FDA (SFP-FDA) radar is proposed to wipe off the angle-range coupling in FDA and improve the target’s angle and range localization accuracy. Compared to the double-pulse FDA, the proposed system can achieve a better performance in range resolution and multitarget identification. The Cramér-Rao lower bound (CRLB) is derived and used to analyze the performance of the proposed system and double-pulse FDA radar. Numerical results are implemented to verify the validity of the proposed scheme.

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“…Unlike the conventional phased array, whose beam steering is fixed at one angle for all range, FDA can form a range-dependent beampattern with its additional degree of freedom. A tiny frequency increment is introduced among the elements, so that FDA has great potential in the joint estimation of target's range and angle [2,3]. Even though several approaches [4][5][6][7] are proposed for target range-angle localization, most of them fail in the case of multiple targets since the peaks of the basic FDA are range-angle-decoupled and range-periodic.…”

Section: Introductionmentioning

confidence: 99%

A Novel Transmit–Receive System of Frequency Diverse Array Radar for Multitarget Localization

Wang

Liu

et al. 2018

Electronics

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The frequency diverse array (FDA) has drawn substantial attention because it provides a new degree of freedom. However, the multitarget localization is fundamentally limited by the range-angle-coupled and range-periodic beampattern of the basic FDA. It has been suggested to design a special FDA configuration to localize targets, but seldom of the existing works consider the design both in transmitting and receiving. In this paper, a transmit–receive system of FDA radar is proposed for the multitarget localization. In order to decouple the beampattern in the range and angle domains, the configurations of subarray-based FDA (SB-FDA) and full-band FDA (FB-FDA) are chosen as transmitter and receiver, respectively. In such a system framework, the receive beamwidth in range domain is only a quarter of the transmission. Then, two typical multitarget scenarios, sparse targets and unresolved targets, are both considered in the multitarget localization. For sparse targets, a proper frequency increment is selected to control the range-periodic transmit and receive mainlobes to focus on a single target, besides being staggered with others. In this way, multitarget localization is achieved in different pulses with monopulse processing. For unresolved targets, a method of intra-pulse beam scanning is proposed to localize each target with little interference from others. We also analyze the system performance in Cramér-Rao lower bound (CRLB) of localization and output signal to interference-plus-noise ratio (SINR). Several simulation results demonstrate the effectiveness of the proposed transmit–receive system in multitarget localization.

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An Overview on Time/Frequency Modulated Array Processing

Cited by 197 publications

References 148 publications

Time-Modulated OFDM Directional Modulation Transmitters

Time-Modulated OFDM Directional Modulation Transmitters

Stepped Frequency Pulse Frequency Diverse Array Radar for Target Localization in Angle and Range Domains

A Novel Transmit–Receive System of Frequency Diverse Array Radar for Multitarget Localization

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