Effects of Reverse Radiation Noise on Millimeter-Wave Radiometric Imaging at Short Range

Hu, Taiyang; Zhang, Xiao; Xu, Jianzhong; Wu, Li

doi:10.2528/pierm11092606

Cited by 8 publications

(6 citation statements)

References 11 publications

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“…The LO is a critical element in the receiver development. Due to a finite mixer LO-RF isolation, the LO signal leakage from LO port to RF port of the mixer will result in reverse radiation and deteriorate the radiometer's performance greatly [17]. The employed LO with a Gunn diode shows a frequency of 94.5 GHz, with output power of 14 dBm and typical frequency stability of 5 MHz/ ∘ C. Besides, an isolator is placed between the coupler and the mixer to reduce the effects of reverse radiation, which performs a maximum insertion loss of 0.9 dB and a minimum isolation of 18 dB at operating frequencies.…”

Section: Receiver Descriptionmentioning

confidence: 99%

A W-Band Radiometer with the Offset Parabolic Antenna for Radiometric Measurements

Peng

et al. 2016

International Journal of Antennas and Propagation

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This paper deals with the development of a W-band noise-adding radiometer which combines the millimeter-wave (MMW) radiometric measurements with a high-resolution imager. The offset parabolic antenna is presented to achieve an accurate measurement and a high resolution. To reduce the cross-polarization level of the antenna, a multimode feed horn with a multistep structure is proposed to match the focal region fields of the reflector. It has advantages over the corrugated horns in lower mass and easier manufacturing. In addition, due to an unavoidable settling time for the noise-adding radiometer output signal passing through the low-pass filter, a theoretical criterion for the optimum duty cycle determination to reject extraneous contributions from the transient is proposed in this paper. The appropriate duty cycle threshold is 0.33 for the developed W-band radiometer. Also, a geometric correction method is presented to correct the obtained passive image suffering from a distortion for a better image interpretation. Preliminary experimental results are given to illustrate and verify the presented techniques.

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Section: Receiver Descriptionmentioning

confidence: 99%

A W-Band Radiometer with the Offset Parabolic Antenna for Radiometric Measurements

Peng

et al. 2016

International Journal of Antennas and Propagation

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“…The schematic diagram of our MMW radiometer and a photograph of the experiment set-up [13] can be seen in Figure 5. The scene energy is collected by a W-band antenna and the frequency is down-converted by mixing with a 94.5GHz oscillator to the intermediate frequency (IF).…”

Section: Experiments Of Two-dimensional Detectionmentioning

confidence: 99%

Ranging Technique Based on Conically Scanned Single Pixel Millimeter Wave Radiometer

Lü

Xiao

et al. 2014

JERA

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Passive millimeter wave detection offers great advantages of covertness and anti-interference in surveillance and concealed weapon detection but suffers from disabilities of distance measurement. Based on the conically scanned single pixel millimeter wave radiometer, this paper presents a ranging method via dual-measurement utilizing the relation between the solid angle of the object and its distance from antenna. Both one-dimensional and two-dimensional detections are considered. For one-dimensional detection, the relation between the solid angle of the object and the range is reflected by the pulse width of the radiometer output, and the pulse widths of the radiometer output in two measurements could be extracted by derivative or threshold method. Then the range is calculated since it is inversely proportional to the pulse width, which is demonstrated in simulation. For two-dimensional imaging, a scale extracting algorithm is developed to search the scale between the object sizes of bi-measured images. Experiments are performed using a 94.5GHz total-power radiometer mounted on conically scanning platform. The obtained radiometric images are processed by the developed algorithm and the results indicated that both the scale extracting algorithm and the ranging method are effective and practical.

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“…For different objects, their capacities in emission, absorption and scattering of electromagnetic radiation within the MMW waveband are different; the characteristic information of the MMW radiation can be obtained through receiving the thermal radiation energy of objects by the high-sensitivity MMW radiometer [1,2]. The research on MMW radiation characteristics of the targets has played an important role in many fields, such as weapon system development, battlefield reconnaissance, range testing, stealth technology [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Research on Millimeter-Wave Radiation Characteristics of Solid Target

Chen¹,

Xu²

2013

PIER M

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Millimeter-wave (MMW) radiation characteristics of solid targets are very complicated, and this paper starts with the research on modeling and simulation of the simple solid metal target. On the basis of the optical property of MMW, the two-ray propagation (direct reflection and ground secondary reflection of the solid target surface) is analyzed by means of the ray tracing theory in the geometrical optics, the radiation temperature calculation model is established. Furthermore, in combination with the panel-method-based geometric model and in accordance with the spatial analytic geometry and vector algebra theory, model calculation of the intersection movement between the radiometer and the target is analyzed and the MATLAB simulation platform for MMW radiation characteristics of the solid target is built. Under the assumed simulation conditions, simulation experiments on three types of solid metal targets (sphere, cylinder and cone) are performed to verify the proposed method in this paper. Meanwhile, comparative analysis between the MMW radiation characteristics of the circular metallic plate and those of the metallic ball with the same radius indicates that the spherical metallic target is equivalent to the non-ideal metallic circular planar target which is increased about 1.3 times in the linear size, and the result is validated through the measured data, which provides more accurate and effective data and theoretical support for target recognition and location in the millimeter-wave passive detection.

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Effects of Reverse Radiation Noise on Millimeter-Wave Radiometric Imaging at Short Range

Cited by 8 publications

References 11 publications

A W-Band Radiometer with the Offset Parabolic Antenna for Radiometric Measurements

A W-Band Radiometer with the Offset Parabolic Antenna for Radiometric Measurements

Ranging Technique Based on Conically Scanned Single Pixel Millimeter Wave Radiometer

Research on Millimeter-Wave Radiation Characteristics of Solid Target

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