Near-Field Gain Expression for Aperture Antenna and Its Application

Xiao, Luyin; Xie, Yongjun; Wu, Peng; Li, Junbao

doi:10.1109/lawp.2021.3076018

Cited by 5 publications

(7 citation statements)

References 15 publications

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“…In the far-field region, the near-field gain is a fixed value without distance and other parameters, which is consistent with the far-field gain definition. Figure 9 displays the near-field gain results of aperture antennas for the radar system [24]. In conclusion, the generalized radar range equation can be applied to analyze more complicated real targets in its working area and its rationality is affirmed by the unity with the radar range equation in the far-field region.…”

Section: Near-field Radar Theorymentioning

confidence: 89%

“…It should be noticed that η is far more than 0 dB in the near-field region. Like the gain of antennas [24], it is unreasonable to assume the RCS value of a target is constant in such a near range from 10λ to 1000λ. Thus, an alternative radar range equation applied to the THz radar system needs to be derived.…”

Section: Generalized Radar Range Equationmentioning

confidence: 99%

“…Thus, an alternative radar range equation applied to the THz radar system needs to be derived. According to the previous research, we have defined the near-field gain and its expression has been derived in [24]. The near-field gain G N and RCS defined in the near-field region σ N (R) are substituted into the radar range equation as…”

Section: Generalized Radar Range Equationmentioning

confidence: 99%

“…The near-field gain for the radar system is defined in [24], which is related to the distance, diameter, aperture illumination, and wavelength in the Fresnel zone. In the far-field region, the near-field gain is a fixed value without distance and other parameters, which is consistent with the far-field gain definition.…”

Section: Near-field Radar Theorymentioning

confidence: 99%

“…In the farfield region, the near-field gain is a fixed value without distance and other parameters, which is consistent with the far-field gain definition. Figure 9 displays the near-field gain results of aperture antennas for the radar system [24]. The near field RCS Expression ( 9) is composed of the RCS with the same direction defined in the far field, the function related with the range R, target dimension, frequency, and the error due to the characteristic in the near-field region.…”

Section: Near-field Radar Theorymentioning

confidence: 99%

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Generalized Radar Range Equation Applied to the Whole Field Region

Xiao

Xie

Gao

et al. 2022

Sensors

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Most terahertz (THz) radar systems can only work in the near-field region, because the THz source power is limited and the size of the target scattered near field is up to tens of kilometers. Such conditions will result in the conventional radar range equation being unsuitable. Therefore, the near-field radar cross section (RCS) formula is given according to the numerical simulation on different targets. By modifying the parameters in the near field, including the gain of radar antennas and the RCS of targets, the generalized radar range equation is proposed. The THz radar working efficiency in the whole range and the simulation of the near-field RCS simulation model were employed to validate its effectiveness. Through comparison with the radar range equation, it can be concluded that the calculation results of the proposed equation are smaller in the near field, and the outcomes in the far field are identical. The proposed generalized radar range equation can be applied to the whole radiation area including the near field and the far field. Furthermore, more complicated real targets are calculated according to the generalized radar range equation and it can be extended from the submillimeter wave band to a much wider band range. Finally, the near-field radar theory is established, which shows its potential application to the radar cross section estimation in the extremely high frequency and fine design of THz radar systems.

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Section: Near-field Radar Theorymentioning

confidence: 89%

Section: Generalized Radar Range Equationmentioning

confidence: 99%

Section: Generalized Radar Range Equationmentioning

confidence: 99%

Section: Near-field Radar Theorymentioning

confidence: 99%

Section: Near-field Radar Theorymentioning

confidence: 99%

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Generalized Radar Range Equation Applied to the Whole Field Region

Xiao

Xie

Gao

et al. 2022

Sensors

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Radar near-field sensing using metasurface for biomedical applications

Bagheri,

Gharamohammadi,

Abu-Sardanah

et al. 2024

Commun Eng

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Metasurfaces, promising technology exemplified by their precise manipulation of incident wave properties and exquisite control over electromagnetic field propagation, offer unparalleled benefits when integrated into radar systems, providing higher resolution and increased sensitivity. Here, we introduce a metasurface-enhanced millimeter-wave radar system for advanced near-field bio-sensing, underscoring its adaptability to the skin-device interface, and heightened diagnostic precision in non-invasive healthcare monitoring. The low-profile planar metasurface, featuring a phase-synthesized array for near-field impedance matching, integrates with radar antennas to concentrate absorbed power density within the skin medium while simultaneously improving the received power level, thereby enhancing sensor signal-to-noise ratio. Measurement verification employs a phantom with material properties resembling human skin within the radar frequency range of 58 to 63 GHz. Results demonstrate a notable increase of over 11 dB in near-field Poynting power density within the phantom model, while radar signal processing analysis indicates a commensurate improvement in signal-to-noise ratio, thus facilitating enhanced sensing in biomedical applications.

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Near-Field Channel Estimation for Extremely Large-Scale Array Communications: A Model-Based Deep Learning Approach

Zhang

Wang²,

Zhang

et al. 2023

IEEE Commun. Lett.

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Extremely large-scale Array (ELAA) promises to deliver ultra-high data rates with more antenna elements. Meanwhile, the increase of antenna elements leads to a wider realm of near-field, which challenges the traditional design of codebooks. In this paper, we propose novel codebook design schemes which provide better quantized correlation with limited overhead. First, we analyze the correlation between codewords and channel vectors uniform linear array (ULA) and uniform planar array (UPA). The correlation formula for the ULA channel can be expressed as an elliptic function, and the correlation formula for the UPA channel can be represented as an ellipsoid formula. Based on the analysis, we design a uniform sampling codebook to maximize the minimum quantized correlation and a dislocation ULA codebook to reduce the number of quantized bits further. Besides, we give a better sampling interval for the codebook of the UPA channel. Numerical results demonstrate the appealing advantages of the proposed codebook over existing methods in quantization bit number and quantization accuracy.

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Near-Field Gain Expression for Aperture Antenna and Its Application

Cited by 5 publications

References 15 publications

Generalized Radar Range Equation Applied to the Whole Field Region

Generalized Radar Range Equation Applied to the Whole Field Region

Radar near-field sensing using metasurface for biomedical applications

Near-Field Channel Estimation for Extremely Large-Scale Array Communications: A Model-Based Deep Learning Approach

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