Advanced Microwave Imaging

Ahmed, Sherif Sayed; Schießl, Andreas; Gumbmann, Frank; Tiebout, M.; Methfessel, Sebastian; Schmidt, Lorenz-Peter

doi:10.1109/mmm.2012.2205772

Cited by 267 publications

(128 citation statements)

References 40 publications

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“…The millimeter-wave (MMW) band is the region of the electromagnetic spectrum between the microwave and terahertz bands, covering the frequency ranges (30-300) GHz [3,4]. With a high atmospheric transmission and little attenuation through textile materials and clothing, images can be formed of objects on persons concealed on or under their clothing [5] with high detection probability; a capability which is driving the developments of this security screening technology [6][7][8][9][10][11]. Imaging applied to security screening applications can either be achieved passively (radiometrically), where the natural thermal radiation emitted and reflected by the object is used or actively (radar), where the transmitter provides artificial MMW radiation to illuminate the subject and the image is formed from the reflected radiation [12].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHZ

Owda

Salmon

Rezgui

2018

PIER B

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Abstract-Due to changes in global security requirements attention is turning to new means by which anomalies on the human body might be identified. For security screening systems operating in the millimeter wave band anomalies can be identified by measuring the emissivities of subjects. As the interaction of millimeter waves with the human body is only a fraction of a millimeter into the skin and clothing has a small, but known effect, precise measurement of the emission and reflection of this radiation will allow comparisons with the norm for that region of the body and person category. A technique to measure the human skin emissivity in vivo over the frequency band 80 GHz to 100 GHz is developed and described. The mean emissivity values of the skin of a sample of 60 healthy participants (36 males and 24 females) measured using a 90 GHz calibrated radiometer were found to range from 0.17±0.005 to 0.68±0.005. The lower values of emissivity are a result of measuring particularly thin skin on the inner wrist, volar side of the forearm, and back of hand, whereas higher values of emissivity are results of measuring thick skin on the outer wrist, dorsal surface of the forearm, and palm of hand. The mean differences in the emissivity between Asian and European male participants were calculated to be in the range of 0.04 to 0.11 over all measurement locations. Experimental measurements of the emissivity for male and female participants having normal and high body mass index indicate that the mean differences in the emissivity are in the range of 0.05 to 0.15 for all measurement locations. These results show the quantitative variations in the skin emissivity between locations, gender, and individuals. The mean differences in the emissivity values between dry and wet skin on the palm of hand and back of hand regions were found to be 0.143 and 0.066 respectively. These results confirm that radiometry can, as a non-contact method, identify surfaces attached to the human skin in tens of seconds. These results indicate a route to machine anomaly detection that may increase the through-put speed, the detection probabilities and reduce the false alarm rates in security screening portals.

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Section: Introductionmentioning

confidence: 99%

Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHZ

Owda

Salmon

Rezgui

2018

PIER B

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“…The IFMM is derived from inverting a forward operator, the FMM. There are three IFMM operators: aggregation (1), translation (2), and disaggregation (3).…”

Section: Ifmm Overviewmentioning

confidence: 99%

“…m obs ,nsource dyadic term is defined and described in [11], 2 , η is the wave impedance, and the indexes in the previous equations are defined as follows [11]:…”

Section: Ifmm Overviewmentioning

confidence: 99%

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A Gpu Implementation of the Inverse Fast Multipole Method for Multi-Bistatic Imaging Applications

Tirado¹,

Ghazi²,

Álvarez-López³

et al. 2017

PIER M

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Abstract-This paper describes a parallel implementation of the Inverse Fast Multipole Method (IFMM) for multi-bistatic imaging configurations. NVIDIAs Compute Unified Device Architecture (CUDA) is used to parallelize and accelerate the imaging algorithm in a Graphics Processing Unit (GPU). The algorithm is validated with synthetic data generated by the Modified Equivalent Current Approximation (MECA) method and experimental data collected by a Frequency-Modulated Continuous Wave (FMCW) radar system operating in the 70-77 GHz frequency band. The presented results show that the IFMM implementation using the CUDA platform is effective at significantly reducing the algorithm computational time, providing a 300X speedup when compared to the single core OpenMP version of the algorithm.

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“…Current advances in the semiconductor technology have made integrated radiofrequency (RF) components at millimeter-wave frequencies available in high quantity [5], allowing for high integration levels and utilizing digital beamforming. An overview of these advanced imaging systems and reconstruction methods is given in [6].To benefit from the high transceiver count required for digital beamforming in multistatic sparse arrays, the cost aspects, space, and integration efficiency also of the antenna array have to be ensured. This becomes much more difficult at millimeter-wave frequencies and for radar applications, where radiation characteristics and the achievable resolution due to bandwidth and the short wavelength are challenging aspects [1].…”

mentioning

confidence: 99%

Size-reduction and suppression of cavity-resonances in hybrid mm-wave antennas for polarimetric measurements

Methfessel

Schmidt

2014

Int. J. Microw. Wireless Technol.

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Size and feed structure are some of the important constraints for using antenna-elements in multi-element two-dimensional arrays, where easy planar integration and appropriate matching with transceiver chips are essential. This applies especially when differential signaling and adaptable polarization are required. Based on a balanced-fed patch-excited cavity-backed horn antenna (hybrid antenna), feeding concepts, and approaches to reduce size are discussed and evaluated in this paper. The influence of the substrate-integrated cavity is analyzed and methods to overcome the restrictions are presented, together with simulated and measured results. The antenna elements are evaluated with regard to their use in multistatic and polarimetric sparse arrays, which will be briefly introduced. The optimized antennas achieve 10 dB return loss, a gain of more than 5 dBi as well as symmetric and homogeneous radiation patterns in amplitude and phase with low crosspolarization in the desired frequency-band of operation between 70 and 80 GHz. I . I N T R O D U C T I O NImaging systems in the millimeter-and microwave regimes are attracting particular attention due to their use in security, medical, and non-destructive-testing systems [1][2][3][4]. Current advances in the semiconductor technology have made integrated radiofrequency (RF) components at millimeter-wave frequencies available in high quantity [5], allowing for high integration levels and utilizing digital beamforming. An overview of these advanced imaging systems and reconstruction methods is given in [6].To benefit from the high transceiver count required for digital beamforming in multistatic sparse arrays, the cost aspects, space, and integration efficiency also of the antenna array have to be ensured. This becomes much more difficult at millimeter-wave frequencies and for radar applications, where radiation characteristics and the achievable resolution due to bandwidth and the short wavelength are challenging aspects [1]. Even more sophisticated systems using sparse periodic arrays with reduced number of antennas rely on appropriately designed antennas [4,7], especially if polarization is used for further examination [3,8].Using a planar, balanced-fed antenna is the first step to an easy integration with differential interfaced monolithic microwave integrated circuits (MMICs) [5]. In [9,10], the concept of a patch-excited horn antenna, hereinafter referred to as the hybrid antenna, is introduced. For achieving a higher and less extensive integration level, this design has to be reduced in size and complexity, while maintaining the performance of the antenna. Challenges are the feeding structure and the performance in proximity to other antennas. After introducing the concept of the antenna and array in Section II, the relevant design improvements of the antenna are presented in Section III. Continuing with the optimization of the structure in Section IV, simulated and measured results of the antennas and arrays are presented and discussed in Section V. I I . A N T...

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Advanced Microwave Imaging

Cited by 267 publications

References 40 publications

Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHZ

Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHZ

A Gpu Implementation of the Inverse Fast Multipole Method for Multi-Bistatic Imaging Applications

Size-reduction and suppression of cavity-resonances in hybrid mm-wave antennas for polarimetric measurements

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