Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging

et al. 2022

IEEE Access

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The design, analysis, implementation and measurement of an integrated V-band receiver front-end based on 0.15 μm GaAs pHEMT process are presented in this paper. The front-end chip uses the super-heterodyne topology which consists of a low noise amplifier, an image reject mixer, and a multiplyby-four (×4) LO chain. In order to minimize the power consumed by LO chain, an active single-ended mixer is designed which requires extremely low LO power of -5 dBm. Meanwhile, the effect of signal coupling in the integrated chip is analyzed and solutions are proposed. By introducing appropriate filters into the circuit and optimizing the overall layout, the imbalance of in-phase and quadrature signals caused by unwanted coupling can be effectively mitigated, thus enhancing the image rejection of the chip. Probe and module tests are applied to the receiver front-end, and the measurement results reveal that the chip achieves -3 ± 0.7 dB conversion gain, 7 dB noise figure and more than 25 dB image rejection ratio in the RF frequency range of 52-56 GHz. Only one supply voltage of 3 V is required for the chip, and total power consumption is 312 mW. Moreover, with a continuously adjustable phase control of 360° and very broadband IF characteristics, the front-end chip is suitable for passive millimeter-wave imaging applications.INDEX TERMS Integrated receiver front-end, V-band, low LO power, high image rejection, 0.15 μm GaAs pHEMT, passive millimeter-wave imaging.

Section: Integrated Receiver Front-end Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A V-Band Integrated Receiver Front-End Based on 0.15 μm GaAs pHEMT Process for Passive Millimeter-Wave Imaging

Gong

et al. 2022

IEEE Access

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“…[4] Moreover, in order to improve imaging sensitivity, spatial resolution, and imaging rates, these systems are being developed toward achieving high integration and large-scale arrays. Beihang University proposed a PMMW imaging system (BHU-1024) for fast and non-cooperative security application scenarios, in which a phased array and a synthetic aperture work synergistically [5,6]. The phased array forms a fan beam and obtains the resolution in the horizontal direction via electric scanning.…”

Section: Introductionmentioning

confidence: 99%

Ka Band Low Channel Mutual Coupling Integrated Packaged Phased Array Receiver Front-End for Passive Millimeter-Wave Imaging

Gong

et al. 2023

Micromachines

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This paper presents a Ka band eight-channel integrated packaged phased array receiver front-end for a passive millimeter-wave imaging system. Since multiple receiving channels are integrated in a given package, the mutual coupling issue affecting the channel will deteriorate imaging quality. Therefore, in this study, the influence of channel mutual coupling on the system array pattern and amplitude phase error is analyzed, and the design requirements are proposed according to the results. During the design implementation, the coupling paths are discussed, and passive circuits in the path are modeled and designed to reduce the level of channel mutual coupling and spatial radiation. Finally, an accurate coupling measurement method for a multi-channel integrated phased array receiver is proposed. The receiver front-end achieves a 28~31 dB single channel gain, a 3.6 dB noise figure, less than −47 dB of channel mutual coupling. Furthermore, the array pattern of the two-dimensional 1024 channel system composed of the front end of the receiver is consistent with the simulation, and the receiver’s performance is verified by a human-body-imaging experiment. The proposed coupling analysis, design, and measurement methods are also applicable to other multi-channel integrated packaged devices.

“…Moreover, in our previous work, a Ka-band passive imaging system was researched and reported [7]; the imaging system achieves better spatial resolution by using 1024 receiving channels, then a large number of correlators is needed for the imaging system. Therefore, compact size is also required for the analog correlator to reduce the size of the passive imaging system.…”

Section: Introductionmentioning

confidence: 99%

A Compact Broadband Analog Complex Correlator with High Correlation Efficiency for Passive Millimeter-Wave Imaging System

et al. 2022

Electronics

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In this paper, the design, fabrication, and measurement of a compact broadband (4–8 GHz) analog complex correlator for a passive millimeter-wave imaging system are presented. To achieve high sensitivity and high integration of the imaging system, the wideband and miniaturization of the correlator are required. The correlator achieves wide bandwidth by using the add-and-square method, which is composed of a six-port circuit and a detection circuit. In order to realize the miniaturization of the correlator, the six-port circuit is realized on the chip base on the 0.15-μm gallium arsenide (GaAs) process. The influence of mismatch of the detection circuit that employs zero-bias Schottky diodes on the correlator is also analyzed to guide the design of the correlator. The measurement results of the designed chips and detector are consistent with the simulation result. Finally, a Sweep-frequency test is applied to the designed correlator, and the measurement results show that, within the frequency range of 4–8 GHz, the correlation amplitude fluctuation is less than 1.9 dB and the correlation efficiency is larger than 99%, which reveal that the correlator is suited for interferometric passive millimeter-wave imaging applications.