• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.52-59
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• 1996

This paper presents a monopulse feed structure with low sidelobe monopulse pattern, which consists of a E-plane corrugated horn and a unfiorm pick-up aperture power divider. Tfhe design methods and epxerimental resutls of the E-plane corrugated feeder are described. Modified hybrid mode analysis and GSM (generalized scattering matrix) methods are introduced to design the E-plane corrugated feed horns. The 24-port corrugated feeder is designed using modified hybrid mode analysis initially and verified using GSM methods. Measurement results show that this feeder has low return loss and sidelobe level at sum and difference channel, respectively.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.229-233
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• 2003

In this paper we theoretically analyze the probability of error for M-ary pulse position modulation (PPM) ultra-wideband (UWB) multiple access system using Gaussian monopulse. The optimum detection of UWB signals using M-ary orthogonal PPM in additive white Gaussian noise (AWGN) and multiple access interference (MAI) is considered, then receiver signal to noise power ratio (SNR) and upper bound fur the bit error rate (BER) are derived. Numerical results considering some practical parameters are presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.884-891
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• 2001

In this paper, We use Antipodal signal for data modulation of Ultra Wideband(UWB) system. This has maximum Euclidean distance and -1 or 0 of correlation values. With adapting this signal to M-ary that and time hopped pattern, We designed multiple access system. UWB Antipodal signal employes Gaussian monopulse and Rayleigh monopulse. Using these signals, we analysis and compare error probability, the number of user and data rate of the two systems under the AWGN.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.5
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• pp.598-605
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• 2016

One of the effective methods for angular deception against monopulse radar is a cross eye technique. The typical cross eye technique can cause significant angular errors to monopulse radar by using two transceivers which transmit the signals with opposite phases. However, typical cross eye systems have high complexity of implementation because two transceivers should be installed with enough distance on the platform. In this paper, we propose a new cross eye technique with single transceiver based on the multipath effect. Then, angular deception performance of the proposed technique is analyzed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.235-244
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• 2014

This paper describes the subarray channel configuration and calibration method for airborne AESA radar antenna. AESA radar demonstrator was designed and implemented for the digital beam-forming performance test of the 12 channel subarray structure. Magnitude and phase difference can be exist between the manufactured subarray channel. In this paper, calibration method for the subarray difference error was suggested. We measured digital monopulse slope in the subarray channel and verified the channel calibration effect. To verify the subarray channel operation, digital monopulse channel was compared with analog monopulse channel performance. AESA radar demonstrator was tested in the ground far field test range. Emulated single target was generated to test the detection and tracking performance of the demonstrator with the same waveform and search pattern. We verified that the detection and tracking performance of the 12 subarray digital monopulse channel was similar with the conventional analog monopulse channel. Also, ABF(Adaptive Beam-Forming) function for the sidelobe jammer was tested and effective operation was verified.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.410-413
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• 2012

This study describes the performance comparison to solve angle ambiguity needed to angle of arrival estimation in 2D radiometer. There are three algorithms to solve its ambiguity such as phase-comparison monopulse method, digital beam-forming method and least square error of the phase difference in 2D radar interferometer. To estimate two direction angles, phase-comparison monopulse method is sequentially applied to azimuth and elevation direction. To analyze the performance of these methods, probability of solving angle ambiguity and execution time have been chosen as performance indexes. Through the Monte Carlo simulation, we have verified that phase-comparison monopulse method is most effective in real-time signal processing application.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.3
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• pp.372-375
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• 2014

A monopulse based on maximum likelihood(ML) in jamming scenario can suppress jamming signal using an inverse matrix of a covariance matrix. In order to achieve adequate suppression of jamming signal, the sufficient number of snapshots is required. However, this is not possible in high PRF scenario, which hinders a real-time tracking. Moreover, even with the large number of snapshots, the estimation accuracy of the target direction is decreased in low JNR(Jammer to Noise Ratio) due to insufficient jammer suppression. In this paper, we propose a monopulse algorithm that doesn't degrade performance significantly with a small number of snapshots and in low JNR. We show its derivation that exploits noise-jammer subspace of a covariance matrix, along with its performance through simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1248-1258
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• 2010

In this paper, a method for simultaneously realizing the sum and difference patterns which are required in the monopulse radar sensor systems, is presented by using single taper array antenna with rectangular microstrip patches. The widths of patches are first determined by the voltage weights which are synthesized for the fundamental array factor patterns to be applied to the monopulse operation by using the sidelobe levels(SLLs) control technique. As the bi-directionally series-fed technique is applied and the lengths of connecting lines between patches are appropriately adjusted, the single array generates two phase-shifted beams which activates out-of-phase and in-phase ports of a $180^{\circ}$ hybrid coupler to synthesize the sum and difference patterns. The simulated results on the configuration designed at 9.5 GHz are compared with measured results showing the validity of the proposed method.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.30-35
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• 2020

In this paper, we analyzed the tracking error for the monopulse radar by controlling the phase difference, amplitude ratio and engagement angle of the cross-eye jammer. Cross-eye jamming is an important jamming method for monopulse radars, which causes a displacement in the radar receiving antenna input and misleads the radar's tracking angle. As a result of analyzing the tracking distance error of the radar while changing the engagement angle between the monopulse radar and jammer, the maximum distance error occurs when the engagement angle is 0° and the phase difference is 180°. It was confirmed that the error decreased to 70% or less of the maximum distance error into 45°~135°. In order to increase the efficiency of jammers, it is necessary to study rotary jammers or multi-channel jammers. This study will be very useful for the design of cross-eye jammers for aircraft and ships.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.209-215
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• 2017

In this paper, an antenna having 2-axes cross monopulse for Ka band millimeter-wave seeker is designed and antenna performance is verified through vacuum-brazing method for fabrication and measurement. Also, by designing and manufacturing a waveguide circulator the antenna including the circulator is measured. Radiating part of the antenna takes optimized slot lengths and offsets from Elliot's array synthesis procedure using the generic algorithm and feeding part for cross monopulse axes uses the folded waveguide to optimize the S-parameter result. Based on this method, the antenna has 33.3 dBi gain, $3.5^{\circ}{\pm}0.5^{\circ}$ beamwidth, below -23 dB SLL through fabricating and measuring. It is found that antenna characteristics is similar to design results.