• Title/Summary/Keyword: Monopulse Comparator

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High-Gain 94 GHz Monopulse Antenna Using Folded Reflectarray (Folded Reflectarray를 이용한 고이득 94 GHz 모노펄스 안테나)

  • Lee, Han-Seung;Chae, Hee-Duck;Chun, Jong-Hoon;Nam, Sang-Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.1
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    • pp.87-94
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    • 2008
  • This paper proposes a high-gain monopulse antenna using the folded reflectarray for a monopulse target-tracking radar systems designed at the center frequency of 94 GHz. In target-tracking radar systems, the angle of arrival of the incoming wave Is determined by comparing the signal received on two or more non-coincident antenna patterns. This is the physical basis of most target-tracking techniques and the comparison is made simultaneously in a monopulse radar systems. In this paper, the antenna consists of polarizing grid, reflectarray, multimode feed horn, and comparator implemented by wavguide. The antenna is able to have three radiation patterns by using the monopulse feed systems assembled by multimode feed horn and comparator. The antenna demonstrates maximum gains 36dB, 33.5dB and 27.2dB at sum mode, azimuth mode, and evevation mode respectively.

A Design of Wideband Monopulse Comparator for W-Band mm-Wave Seeker Applications (W-대역 밀리미터파 탐색기용 광대역 모노펄스 비교기 설계)

  • Kim, Dong-Yeon;Lim, Youngjoon;Jung, Chae-Hyun;Park, Chang-Hyun;Nam, Sangwook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.2
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    • pp.224-227
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    • 2016
  • This paper proposes a design of W-band mm-wave wideband monopulse comparator using waveguide structure for applications. The main idea of proposed design is to combine a self-compensating phase shifter on $90^{\circ}$ hybrid for wideband $180^{\circ}$ hybrid. Using multiple conventional phase shifters, because of their narrow-band characteristics, tends to restrict working bandwidth of system including antennas. Proposed comparator could relieve the problem since it applies the self-compensating phase shifter. The comparator has waveguide structure so it shows excellent characteristic in loss. It also show wideband characteristic in amplitude and phase response between ports.

Monopulse L-Band Dipole Feed For The Satellite Tracking (위성 추적용 Monopulse L-Band Dipole Feed부의 제작)

  • Cheon, B.J.;Hong, S.Y.;Lee, J.H.;Ra, J.W.
    • Proceedings of the KIEE Conference
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    • 1987.07a
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    • pp.82-85
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    • 1987
  • Electromagnetic waves from the satellite may be utilized to direct the tracking antenna toward the satellite. We design and fabricate the feed appropriate to the monopulse tracking technique which derive angle-error information on the basis of a single pulse. The feed consists of five cavity-backed turnstile elements mounted on a common ground plane. The turnstile dipole are connected to a set of five quadrature hybrids which convert the dual linear polarization into dual circular polarization. The five feed outputs are then processed in the monopulse comparator which is constructed in microstrip for compactness.

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Design of Dual-Polarized Monopulse Cassegrain Antenna for W-Band Millimeter-Wave Seeker (W-대역 탐색기용 이중편파 모노펄스 카세그레인 안테나 설계)

  • Lee, Kook Joo;Jung, Chae-Hyun;Baek, Jong-Gyun;Park, Chang-Hyun;Nam, Sangwook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.3
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    • pp.261-268
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    • 2016
  • In this paper, dual-polarized monopulse cassegrain antenna for W-band millimeter-wave seeker was proposed and the performances were verified by the measured results of the fabricated antenna. Dual-polarized monopulse Cassegrain antenna consists of main/subreflector, dual-polarized feed horn and monopulse comparator. The proposed feed horn has $2{\times}2$ array square waveguide feeding structure to make monopulse signals and it was designed using 90 degree rotational symmetric structure to receive dual-polarized signals. At the sum and difference channel, the measured vertical and horizontal polarization radiation pattern were similar. Measurement gains are 35.1 dBi for v-pol. and 35.6 dBi for h-pol. at the center frequency with 0.5dBi difference between each polarization and the side lobe level is below -21.6 dB.

Waveguide Broad-Wall Slot Array Monopulse Antenna for Millimeter-Wave Seeker Using Dip Brazing Method (딥 브레이징 제작 기법을 이용한 밀리미터파 탐색기용 도파관 광벽 슬롯 배열 모노펄스 안테나)

  • Baek, Jong-Gyun;Jung, Chae-Hyun;Lee, Kook-Joo;Park, Chang-Hyun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.11
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    • pp.1020-1026
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    • 2015
  • In this paper, the design of longitudinal shunt slot array monopulse antenna in the broad wall of waveguide for Ka band millimeter-wave seeker, Dip-Brazing method for fabrication and experiment results are presented. The proposed antenna consists of radiating slots by using Elliot's array synthesis procedure, probe-exciting feed structure for improving the return loss bandwidth and monopulse comparator. Element weigthings in the array have been calculated by continuous Taylor aperture distribution. Also, the simulation tool has been used to characterize the individual isolated slot, which has subsequently been used in Elliot's method to design the slot array efficiently. The designed antenna is fabricated using Dip-Brazing method. The gain of measured antenna is 28.4 dBi. Antenna beamwidth and side lobe levels are similar to the design result we expect.

Optimization of a Broadband Waveguide Magic-T for X-Band Monopulse Tracking Radars (X-Band 모노펄스 추적 레이더를 위한 광대역 도파관 Magic-T 최적화 설계)

  • Hwang, Keum-Cheol
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.10
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    • pp.1042-1049
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    • 2009
  • Design and optimization of a broadband waveguide magic-T was performed for X-Band tracking radars. A multi-stepped conducting cylinder was used to enhance the bandwidth performance of the conventional waveguide magic-Ts. Particles swarm optimization in conjunction with genetic algorithm was employed to obtain the optimized geometrical parameters. The optimized design exhibits low reflection coefficient below -20 dB at all waveguide ports with frequency bandwidth of 12%. The transmission loss and difference are within 0.2 dB and 0.1 dB, respectively. Measured results are also shown to be in good agreement with the simulated results. Finally, the bandwidth performances for five and seven-stepped conducting cylinders are also investigated.