• Title/Summary/Keyword: Cassegrain Antenna

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GAIN DEGRADATION OF KVN 21-M SHAPED CASSEGRAIN ANTENNA DUE TO MISALIGNMENT OF ANTENNA OPTICS

  • Chung Moon-Hee;Byun, Do-Young;Khaikin Vladimir B.
    • Journal of Astronomy and Space Sciences
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    • v.23 no.4
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    • pp.327-336
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    • 2006
  • In this paper, gain loss of KVN (Korean VLBI Network) 21-m shaped Cassegrain antenna due to misalignment of antenna optics is calculated using ray-tracing method. It enables us to estimate alignment tolerances of feed and sub-reflector positioning. According to numerical results, KVN 21-m shaped Cassegrain antenna's gain loss is more sensitive to positions of feed and sub-reflector than in case of the equivalent classical Cassegrain antenna. The result of calculation is believed to be utilized as a possible guideline when checking the performance of the antenna system.

A W-band Cassegrain Antenna of the Target Detecting Fuze Sensor (표적감지 신관센서용 W-대역 카세그레인 안테나)

  • Jung, Myung-Suk;Uhm, Won-Young;Kim, Wan-Joo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.9 no.3
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    • pp.101-108
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    • 2006
  • This paper describes the design, fabrication, and measured results of a W-band Cassegrain antenna suitable for the target detecting fuze sensor. The Cassegrain antenna is designed using MATLAB and MWS of CST. We use the multi-mode horn antenna as a feeder. The measurement results are as follows: The gain is about 41dB; SLL is 17.7dB; 3dB beamwidth is about $1.51^{\circ}$ in E-plane and $1.45^{\circ}$ in H-plane. The magnitude of leakage signals is about 43.5mVpp when the fabricated antenna and the transceiver of the fuze sensor ire combined. As a result, the designed W-band Cassegrain antenna could be quite applicable to the target detecting fuze sensor.

Design of Ka-band Feed Horn and Cassegrain Antenna (Ka-band 대역의 급전 혼과 카셋그레인 안테나 개발)

  • Ahn, Seung-Beom;Choo, Ho-Sung;Kang, Jin-Seob
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.8
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    • pp.943-953
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    • 2007
  • In this paper, we propose a Cassegrain antenna with a scalar feed horn opt rating in Ka-band. For an effective EM simulation of the Cassegrain antenna, the near-field of the feed hone is used ai the equivalent source of the Cassegrain antenna using the surface equivalent theorem. A corrugated circular horn operating with $HE_{11}$ mode is used as the feed horn. The angle and feed center of the main and sub reflectors are optimized to achieve maximum antenna efficiency. The designed feed horn shows the gain of 19dBi, the side-lobe level of less than -25dB and the half power beam width of $20^{\circ}$ at 33 GHz. The Cassegrain antenna shows the gain of 41dBi, the efficiency of 60%, the side-lobe level of less than -20dB and the half power beam width of $1.2^{\circ}$.

The Design of X-band Cassegrain Antenna for Spill-over Suppression (Spill-over 억제를 위한 X-band 카세그레인 안테나 설계 연구)

  • Lee Woo-Sang;Jang Won;Lee Byoung-Moo;Yang Gi-Joo;Lee Sang-Heun;Yoon Young-Joong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.9 s.112
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    • pp.829-835
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    • 2006
  • In this paper, new structure of the Cassegrain reflector antenna whose spill-over is efficiently reduced by modified reflectors is proposed for high power. It can be achieved by designing the geometry of subreflector in Cassegrain system using two hyperbolic curves in order to be suitable a lager beamwidth of feeding pattern without broadening main reflector. Finally, radiation efficiency and side lobe level of the proposed Cassegrain reflector antenna can be improved respectively 9 %, 10 dB than conventional one.

Design of W-Band Cassegrain Antenna for Beam Steering (빔 조향을 위한 W-대역 카세그레인 안테나 설계)

  • Park, Myung-Hoon;Han, Jun-Yong;Lee, Taek-Kyung;Lee, Jae-Wook;Oh, Gyung-Hyun;Song, Sung-Chan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.4
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    • pp.358-368
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    • 2016
  • In this paper, for the mechanical beam steering of the Cassegrain antenna, the steering performances of the main reflector tilting method are characterized, and the Cassegrain antenna for the antenna rotating method is designed and its performances are measured. In the Cassegrain antenna operating at W-band, the changes of characteristics due to changes in the sizes of the main/sub-reflectors and other structural changes are analyzed to obtain the structural variables satisfying the performance goal. The manufactured antenna in W-band shows the measured gain of 42.08 dBi, 3 dB beamwidth of $1.32^{\circ}$, $1.14^{\circ}$ and the return loss($S_{11}$) of -23.58 dB at the center frequency of 94 GHz.

Design of the Shaped Offset Cassegrain Antenna System Combined with Corrugated Conical Feed Horn

  • Yang, Doo-Yeong
    • Journal of IKEEE
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    • v.3 no.1 s.4
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    • pp.1-10
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    • 1999
  • In this paper, the design for the shaped offset cassegrain antenna system combined with corrugated feed horn is presented. First, spherical-mode wave theory is applied to the corrugated conical horn and its radiation patterns are investigated. Using the radiation patterns, design data of the corrugated conical horn are obtained by efficiency investigation of horn antenna. When the investigation is completed, the flare angle and length of the corrugated conical horn is determined. Next, the main and sub-reflector is designed using Snellis law and the conservation principle of energy. Then the uniform direction and energy density of the traveling wave at the aperture of the main-reflector is obtained. The maximum size of the main-reflector is determined by investigation of the illumination and spillover efficiency. Finally, the curvature of the main-reflector is modified to satisfy the condition of the uniform phase. From the calculated efficiencies, the designed site of the main-reflector and sub-reflector, system gain of the shaped offset cassegrain antenna has been obtained 40.5dB in Ka-band frequency. It has better characteristics than the result of SABOR with 39dB gain.

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The Study on the Design and Manufacturing of Large Aperture Cassegrain antenna (대구경 카세그레인 안테나의 설계 및 제작 고찰)

  • 박정기;이돈신
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.19 no.2
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    • pp.14-22
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    • 1982
  • The design and manufacfure technology of the large aperture cassegrain antenna was first studied in the country, and its performances in a trial manufactured product are measured and compared. In order to design this cassegrain antenna with reference to several literatures, the schemed order was decided. Especially, for the cassegrain antenna of 4.6m diameter which is becoming the television receiving antenna directly from satellite, in advanced countries, the 1/12 sized small section of its parabolic curved surface is made primarily with the precision of less difference than 1/16λ depth. Cares are taken also on the computer program so that the size and position of primary radiator may satisfy the minimum blocking with the given sub-reflector. The preformances of the designed antenna are shown as being 43dB in gain, 1.15 or less in VSWR, 1.1$^{\circ}$ of beam angle etc., and found to be not worse than those of foreign productions with similar type and size.

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Design of the Shaped Cassegrain Antenna Considering the Excited Power Function (급전 함수를 고려한 수정곡면 캐서그레인 안테나 설계)

  • Kong, Ki-Bok;Kim, Jong-Sung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.9
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    • pp.908-914
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    • 2013
  • A shaped Cassegrain antenna is designed from the condition of the same path length at the equi-phase surface by using the conservation of energy and Snell's law. In order to improve the phase error efficiency of aperture surface, the surface profile of the main and sub-reflectors is found to satisfy the power distribution and the equi-phase condition at the aperture surface. The sidelobe levels of 36.4 dB and 33.9 dB are achieved at the AZ and EL planes, respectively from numerical calculation by physical optics method at Ku band and the directivity of designed antenna is 10 percent greater than that of conventional antenna.

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.

Design of Metamaterial-Inspired FSS Sub-Reflector for a Dual-Band Offset Cassegrain Reflector Antenna (이중대역 오프셋 카세그레인 반사판 안테나용 메타재질구조 모사 주파수 선택표면 부반사판 설계)

  • Kim, Hyeonsu;Kahng, Sungtek;Khattak, M. Kamran;Jeon, Jinsu;Park, Jeong-hoon
    • Journal of Satellite, Information and Communications
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    • v.10 no.2
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    • pp.34-39
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    • 2015
  • In this paper, a design of an offset Cassegrain antenna is proposed for Ku and Ka dual-band without increasing the antenna size. For Efficiency of computation and implementation, the frequency selectivity surface (FSS) of reflecting the Ka-band signal and passing the Ku-band is provided for the sub-reflector instead of the main reflector. The proposed FSS hyperboloid sub-reflector is the periodic structure of a unit cell comprising octagon metal rings embedded in the multiple layers. The proposed design is verified for 19 GHz and 45 GHz bands by the use of precise electromagneitc-field simulations.