• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제29권2호
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• pp.146-149
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• 2018

A monopulse sensor is used to estimate the angle of a target with respect to each received single pulse. It is well known that the cross-eye technique can result in an angle deception effect against monopulse sensors. To verify this effect, we propose a test environment configuration for the angle deception using monopulse receiving antennae and cross-eye transmitters in an anechoic chamber. Using the proposed test environment configuration, we have measured powers of the sum and difference of the signals received by the monopulse receiving antennae when the distance of the two cross-eye transmitters is varied. Finally, the angle deception performance related to the powers of the sum and difference signals was analyzed.

• Applied Biological Chemistry
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• 제40권5호
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• pp.409-415
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• 1997

In order to find out the relationship between contained water and coloring rate of thiamine monosalts in preparations, three kinds of thiamine monorhodanate, -monoiodide, -monobromide were manufactured and investigated as powders, granules and compressed tablets, respectively. Apparent coloring rate constants and solubility in accordance with temperature changes were measured. Nature of contained water and coloration of thiamine monosalts in preparations was examined in detail. It was thereby found that if water attached in a free state, coloration occured whose degree was approximately proportional to the quantity of such water, and a linear relation was found to hold between the logarithm of the apparent coloring rate constants and the reciprocal of the absolute temperature in granules and compressed tablets.

• Journal of Convergence for Information Technology
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• 제11권8호
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• pp.23-28
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• 2021

In this paper, we analyze the tracking errors of monopulse radar according to the JSR of retrodirective cross-eye and radar skin return signals. The cross-eye jammer gain(G_c) is used to calculate the radar tracking errors, and the relationship between the jammer gain and the JSR is represented mathematically. We analyze the radar tracking errors by varying the tracking angle and JSR. Analysis results of the phase difference(ϕ) and amplitude ratio(a) between the two jammer signals and the changing JSR show that the closer the phase difference of the two jammer signals is to 180, the greater the tracking error and it shows that if the JSR is above 20dB, the tracking errors no longer increase. This work presents an effective utilization of retrodirective cross-eye jammers through various tracking error analyses based on the JSR, tracking angles, two-jammer phase differences and amplitude ratios of two-jammer signals.

• Journal of Digital Convergence
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• 제19권12호
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• pp.339-345
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• 2021

In this paper, estimation angle performance analysis of amplitude-comparison monopulse radar under additive noise effect is dealt with. When uncorrelated white noises are added to the squinted beams, the angle estimation performance is analyzed through the mean square error(MSE). The numerical integration-based mean square error result completely overlaps the Monte Carlo-based mean square error result, which corresponds to 99.8% of the Monte Carlo-based mean square error result. In addition, the mean square error analysis method based on numerical integration has a much faster operation time than the mean square error method based on Monte Carlo. the angle estimation performance of the amplitude comparison monopulse radar can be efficiently analyzed in various noise environments through the proposed numerical integration-based mean square error method.

• The Journal of Korean Institute of Information Technology
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• 제16권12호
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• pp.93-100
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• 2018

Inverse Synthetic Aperture Radar(ISAR) image is 2-dimensional radar cross section distributions of a target. For target approaching along radar's line of sight(LOS), the bistatic ISAR can compensate for the weakness of the monostatic ISAR which can not obtain the vertical resolution of the image. However, bistatic ISAR have longer processing times and variability in scattering mechanisms than monostatic ISAR, so target identification using only bistatic ISAR images can be inefficient. Therefore, this paper analyzes target identification performance using monostatic and bistatic ISAR images of targets approaching along radar's LOS and proposes a method of target identification through fusion of two radars. Simulation results demonstrate that identification performance through fusion is more efficient than identification performance using only monostatic, bistatic ISAR images.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제23권10호
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• pp.1261-1268
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• 2019

In this paper, we present the analysis of a novel monopole antenna with a reflector. The proposed monopole antenna is printed on a TRF-45 substrate, and the reflector, which is positioned near the base of the antenna, is printed on the FR-4 substrate. Positioning the reflector near the base of the antenna was found to suppress current radiation toward the back of the monopole antenna. Comparative analysis of the proposed monopole antenna and a conventional monopole antenna without a reflector revealed that the bandwidths of the antenna with and without a reflector were 2.65 GHz and 2.88 GHz, respectively. Additionally, the antenna without a reflector was observed to have a bi-directional radiation pattern in the E-plane, and an omni-directional radiation pattern in the H-plane. However, only the antenna with a reflector was found to suppress back radiation, and provide non-uniform directional radiation in the E-plane and H-plane.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제23권6호
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• pp.47-53
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• 2023

In this paper, We designed a waveguide-type feed structure that converts millimeter wave dual-polarized signals into monopulse signals and presented a manufacturing method. At millimeter-wave such as the W band, the size of the waveguide is very small, making it very difficult to manufacture complex structures. Therefore, because manufacturability is important for the waveguide-type feed structure in the millimeter-wave, electro forming and diffusion bonding were proposed and verified in this study. The designed monopulse feed structure consists of eight 180° hybrids that combine 90° hybrids and self-compensating phase shifters, and four OMTs to separate dual polarization. The designed feed structure was designed to facilitate electro forming and diffusion bonding, and the manufactured feed structure was verified through a network analyzer. It was confirmed that the two proposed production methods produce a monopulse signal well through the measured magnitude and phase of the port.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제13권9호
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• pp.932-936
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• 2002

This paper has been studied a calibration techniques in CISPR A for 1 m monopole antenna factor in the frequency range below 30 MHz. The equivalent capacitance substitution method uses a dummy antenna in place of the actual rod element. Dummy antenna measure frequency from 150 kHz to 30 MHz and good results factor from 150 kHz to 25 MHz compare to using 1 m monopole antenna factor. It will be use to substitute dummy antenna factor for 1 m monopole antenna factor.

• Journal of the Korea Institute of Military Science and Technology
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• 제4권1호
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• pp.83-92
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• 2001

In this paper, the monopulse channel receiver which can be matched between channels through a wide bandwidth has been proposed. The effects of the gain and phase imbalance between channels on the slope of monopulse error signal were analyzed. Also, the matching method between channels in a wide bandwidth was proposed, by which monopulse slope could be stabilized. Using the implemented monopulse radar system the monopulse slope was measured in the anechoic chamber which include the moving horn antenna and the target signal generator. The results show that the wide band matching method is useful and applicable to various channel receivers

• Journal of the Korea Institute of Military Science and Technology
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• 제20권2호
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• pp.272-278
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• 2017

In this paper, we consider a single-channel amplitude comparison monopulse system(SCACMS). The monopulse ratio curve(MR-C) of the SCACMS can be controlled by an amplitude difference between sum and different signal, a phase difference and the coefficient of the signal processor. We first propose the SCACMS with multiple variables, and then apply a genetic algorithm to optimize the multiple variables in terms of minimizing a root mean square error. The simulation results show that when three variables of the SCACMS are jointly optimized, the linear region of the MR-C can be extended approximately 187 % compared to that of two variables.