Design of a quasioptical scanning system for a fast mobile FMCW terahertz imaging system

Mohammadzadeh, Shiva; Friederich, Fabian

doi:10.1088/1742-6596/1537/1/012017

Cited by 9 publications

(5 citation statements)

References 6 publications

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“…In comparison to expensive and bulky lab instrumentation devices such as vector network analyzers (VNAs), frequency modulated continuous wave (FMCW) sensors allow for a higher degree of flexibility and improved robustness, due to the high level of integration. Therefore they offer advantages in harsh industrial environments [1] or when a mobile or scanning operation is required [2]. Furthermore, the FMCW principle allows for faster sweep times, making measurements in dynamic environments feasible [3].…”

Section: Introductionmentioning

confidence: 99%

Versatile 126–182 GHz UWB D-Band FMCW Radar for Industrial and Scientific Applications

Küppers¹,

Jaeschke²,

Pohl

et al. 2022

IEEE Sens. Lett.

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In this paper a D-band frequency modulated continuous wave (FMCW) radar for industrial and scientific applications is presented. It covers an ultra-wide 56 GHz sweep bandwidth (126 GHz-182 GHz, 36.4%) and is based on a custom 1 TRX + 2 RX SiGe transceiver MMIC manufactured in Infineon's B11HFC 130 nm BiCMOS process with an T of 250 GHz and max of 370 GHz. An innovative versatile multichannel edge-launch waveguide frontend-module architecture allows covering applications requiring dual polarization sensing or azimuth & elevation angle-of-arrival estimation based on the same mm-wave circuit board. The FMCW sweeper is based on measurement equipment grade commercial fractional-N PLL synthesizers in an offset dual-loop configuration for highly linear wideband FMCW sweep generation with a phase noise of better than -80 dBc/Hz ( off > 10 kHz) and superior performance even for ultra-fast ramp slopes of more than 56 GHz / 1 ms. Intermediate frequency (IF) signals of a single target measurement are presented to demonstrate the dynamic range capabilities of the FMCW radar. An SNR of 81 dB is achieved using a metal plate reflector target in free space. Due to the ultra-wide bandwidth and the resulting calibrated range resolution of 2.7 mm (-3 dB width, Tukey window), target separation is even possible in dense multi-target environments. Additionally, synthetic aperture radar (SAR) images are presented as an example application utilizing the high range resolution capabilities.

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Section: Introductionmentioning

confidence: 99%

Versatile 126–182 GHz UWB D-Band FMCW Radar for Industrial and Scientific Applications

Küppers¹,

Jaeschke²,

Pohl

et al. 2022

IEEE Sens. Lett.

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show abstract

“…These objective lenses are increasingly applied in microwave and terahertz applications for 3D imaging [22], food safety inspection [23], non-destructive testing [24], etc. Thanks to the nondispersive characteristics of the available lens fabrication material in terahertz and sub-terahertz, f-θ lenses are incorporated with various transmitters and receivers operating in this frequency region, such as FMCW radars with varying bandwidths [22,24,25] and TDS systems up to 1. 25 THz [26].…”

Section: Design Of the F-θ Opticsmentioning

confidence: 99%

Coherent Off-Axis Terahertz Tomography Addressing a Multi-Channel Array with F-theta Optics

May,

Mohammadzadeh,

Keil

et al. 2023

Preprint

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Terahertz tomography is a promising method among non-destructive inspection techniques to detect faults and defects in dielectric samples. Image quality recently significantly improved through the incorporation of a priori information and off-axis data. However, this improvement has come at the cost of increased measurement time. To aim toward industrial applications, it is therefore necessary to speed up the measurement by parallelizing the data acquisition employing multi-channel setups. In this work, we present two tomographic frequency-modulated continuous wave (FMCW) systems working at a bandwidth of 230-320 GHz, equipped with an eight-channel detector array, and compare their imaging results with a single-pixel setup. While in the first system, the additional channels are used exclusively to detect radiation refracted by the sample, the second system features an f-θ lens, focusing the beam at different positions on its flat focal plane, and thus utilizing the whole detector array directly. The usage of the f-θ lens in combination with a scanning mirror eliminates the necessity of the formerly used slow translation of a single-pixel transmitter. As a result acquisition time decreases by a factor of four to five, respectively, in comparison to the single-pixel setup.

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Section: Design Of the F-θ Opticsmentioning

confidence: 99%

Coherent Off-Axis Terahertz Tomography with a Multi-Channel 2 Array and F-theta Optics

May,

Mohammadzadeh,

Keil

et al. 2023

Preprint

View full text Add to dashboard Cite

Terahertz tomography is a promising method among non-destructive inspection techniques to detect faults and defects in dielectric samples. Image quality recently significantly improved through the incorporation of a priori information and off-axis data. However, this improvement has come at the cost of increased measurement time. To aim toward industrial applications, it is therefore necessary to speed up the measurement by parallelizing the data acquisition employing multi-channel setups. In this work, we present two tomographic frequency-modulated continuous wave (FMCW) systems working at a bandwidth of 230-320 GHz, equipped with an eight-channel detector array, and compare their imaging results with a single-pixel setup. While in the first system, the additional channels are used exclusively to detect radiation refracted by the sample, the second system features an f-θ lens, focusing the beam at different positions on its flat focal plane, and thus utilizing the whole detector array directly. The usage of the f-θ lens in combination with a scanning mirror eliminates the necessity of the formerly used slow translation of a single-pixel transmitter. This opens up the potential for a significant increase in acquisition speed, in our case by a factor of four to five, respectively.

show abstract

Design of a quasioptical scanning system for a fast mobile FMCW terahertz imaging system

Cited by 9 publications

References 6 publications

Versatile 126–182 GHz UWB D-Band FMCW Radar for Industrial and Scientific Applications

Versatile 126–182 GHz UWB D-Band FMCW Radar for Industrial and Scientific Applications

Coherent Off-Axis Terahertz Tomography Addressing a Multi-Channel Array with F-theta Optics

Coherent Off-Axis Terahertz Tomography with a Multi-Channel 2 Array and F-theta Optics

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