• Title/Summary/Keyword: axial ratio bandwidth

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Design Method of a Circularly-Polarized Antenna Using Fabry-Perot Cavity Structure

  • Ju, Jeong-Ho;Kim, Dong-Ho;Lee, Wang-Joo;Choi, Jae-Ick
    • ETRI Journal
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    • v.33 no.2
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    • pp.163-168
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    • 2011
  • A Fabry-Perot cavity (FPC) antenna producing both high-gain and circularly-polarized (CP) behavior is proposed. To increase antenna gain and obtain CP characteristics, a superstrate composed of square patches with a pair of truncated corners is placed above the linearly polarized patch antenna with an approximately half-wavelength distance from the ground plane at the operating frequency. The proposed antenna has the advantages of high gain, a simple design, and an excellent boresight axial ratio over the operating frequency bandwidth. Moreover, used in an FPC antenna, the proposed superstrate converts a linear polarization produced by a patch antenna into a circular polarization. In addition, the cavity antenna produces left-hand circular-polarization and right-hand circular-polarization when a patch antenna inside the cavity generates x-direction and y-direction polarization, respectively. The measured and simulated results verify the performance of the antenna.

A Super-Wideband Dipole Antenna With a Self-Complementary Structure (자기상보 구조를 갖는 초광대역 다이폴 안테나)

  • Park, Won Bin;Kwon, Oh Heon;Lee, Sungwoo;Lee, Jong Min;Park, Young Mi;Hwang, Keum Cheol
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.11
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    • pp.1414-1416
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    • 2016
  • In this paper, a SWB (Super-WideBand) dipole antenna with self-complementary structure is proposed for signal intelligence. The proposed antenna consists of a self-complementary dipole antenna and a tapered balun for balanced feeding. The measured -10 dB reflection bandwidth of the proposed antenna is more than 28:1 (0.73-20 GHz) and 3 dB axial ratio bandwidth is 3.25:1 (1.91-6.22 GHz) with RHCP (Right Hand Circular Polarization) at +z direction. The measured radiation patterns are omni-directional in lower frequency band and bi-directional in higher frequency band. The measured peak gain within -10 dB reflection bandwidth varies from 2.83 dBi to 7.66 dBi.

Characteristics of Sequentially Rotated Array Microstrip Antennas Using Each Other Phase Delay (서로 다른 위상지연을 갖는 시퀀셜 로테이션 배열 마이크로스트립 안테나 특성)

  • 한봉희;김남현;노광현;강영진
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.7A
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    • pp.537-546
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    • 2003
  • This paper proposes an aperture coupled circular polarized patch antenna operating at ISM band(5GHz). For improving the characteristic and performance of broadband and circular polarization at single circular polarized patch antenna. We designed and analyzed the sequentially rotated arrayed(SRA) using phase delay of 0$^{\circ}$, 90$^{\circ}$, 180$^{\circ}$, 270$^{\circ}$and 0$^{\circ}$, 45$^{\circ}$, 90$^{\circ}$, 135$^{\circ}$. Experimental result, the SRA antenna using phase delay of 90$^{\circ}$and 45$^{\circ}$are improved at the wideband and axial ratio. Also, the SRA antenna using phase delay of 45$^{\circ}$verified that it is better bandwidth and axial ratio than the SRA antenna using phase delay of 90$^{\circ}$.

A Circular Microstrip Patch Antenna for Switchable Polarization Using PIN Diodes (PIN 다이오드를 이용한 편파 변환 마이크로스트립 원형 패치 안테나)

  • Lee Kun-Joon;Jang Tai-Un;Kim Young-Sik
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.1 s.104
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    • pp.60-66
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    • 2006
  • In this paper, a circular microstrip patch antenna for switchable polarization is presented. For the switchable polarization, pairs of tuning stubs and two PIN diodes are utilized. By independently setting the PIN diodes on or off, the antenna produces either linear polarization or circular polarization. From the results, the -10 dB impedance bandwidths of 57.0 MHz($2.4\%$) and 50.0 MHz($2.1\%$) when operated in the linear polarization, and the 3 dB axial ratio bandwidth of $1.3\%$ with minimum of 0.2 and 0.9 dB in the circular polarization have been observed.

Design of a Dual-Band Square-Waveguide Iris Polarizer (이중대역 정사각형 도파관 아이리스 편파기 설계)

  • Hwang Soon-Mi;Ko Han-Woong;Park Dong-Hee;Yun So-Hyeun;Uhm Man-Seok;Ahn Bierng-Chearl
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.2 s.93
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    • pp.113-119
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    • 2005
  • In this paper, we present methods for designing a square-waveguide iris polarizer operating at dual frequency bands. Methods are presented fur determining the number of ires, iris thickness, iris height and spacing between ires so that the input reflection is low and the axial-ratio bandwidth is optimized at two frequency bands. As an example of the application of the proposed method, a polarizer operating at 21 GHz and 31 GHz bands is designed, fabricated and tested. The fabricated polarizer shows a reflection coefficient less than -35 dB and an axial ratio less than 0.3 dB at $20.8\~21.2\;GHz$ and $30.6\~31.0\;GHz$.

Design and Fabrication of Circularly Polarization Antenna for Electronic Toll Collection System (ETCS용 원형편파 안테나의 설계 및 제작)

  • Lee, Sang-Mok;Yoon, Joong-Han;Kim, Heung-Soo
    • Journal of IKEEE
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    • v.6 no.1 s.10
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    • pp.40-46
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    • 2002
  • In this paper, a microstrip array antenna is designed, fabricated and measured for ETCS(Electronic Toll Collection System). To reduce effect of external propagation environment, we use edge-cuffed element and to obtain wider axial ratio and increased bandwidth, we use the sequential rotation array method. Also to fulfill ETCS, roadside equipment are designed to be provide a radiation pattern which can accurately pinpoint the designated communication area without interference of another lanes. And we make and apply an absorber to the array antenna to reduce SLL(Side Lobe Level). From the measurement, we get that return-loss at center frequency is -20.675dB, axial ratio is 0.35dB and the gain is 20.26dBi. And we found that SLL is reduced.

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THE DEVELOPMENT OF CIRCULARLY POLARIZED SYNTHETIC APERTURE RADAR SENSOR MOUNTED ON UNMANNED AERIAL VEHICLE

  • Baharuddin, Merna;Akbar, Prilando Rizki;Sumantyo, Josaphat Tetuko Sri;Kuze, Hiroaki
    • Proceedings of the KSRS Conference
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    • 2008.10a
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    • pp.441-444
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    • 2008
  • This paper describes the development of a circularly polarized microstrip antenna, as a part of the Circularly Polarized Synthetic Aperture Radar (CP-SAR) sensor which is currently under developed at the Microwave Remote Sensing Laboratory (MRSL) in Chiba University. CP-SAR is a new type of sensor developed for the purpose of remote sensing. With this sensor, lower-noise data/image will be obtained due to the absence of depolarization problems from propagation encounter in linearly polarized synthetic aperture radar. As well the data/images obtained will be investigated as the Axial Ratio Image (ARI), which is a new data that hopefully will reveal unique various backscattering characteristics. The sensor will be mounted on an Unmanned Aerial Vehicle (UAV) which will be aimed for fundamental research and applications. The microstrip antenna works in the frequency of 1.27 GHz (L-Band). The microstrip antenna utilized the proximity-coupled method of feeding. Initially, the optimization process of the single patch antenna design involving modifying the microstrip line feed to yield a high gain (above 5 dBi) and low return loss (below -10 dB). A minimum of 10 MHz bandwidth is targeted at below 3 dB of Axial Ratio for the circularly polarized antenna. A planar array from the single patch is formed next. Consideration for the array design is the beam radiation pattern in the azimuth and elevation plane which is specified based on the electrical and mechanical constraints of the UAV CP-SAR system. This research will contribute in the field of radar for remote sensing technology. The potential application is for landcover, disaster monitoring, snow cover, and oceanography mapping.

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Characteristics of Sequentially-Rotated Array Antenna by Varying Sequential Array Parameter (배열 정수 변화에 의한 순차 회전 배열 안테나의 특성)

  • Han, Jeong-Se;Lee, Hyun-Sung;Seo, Dong-Kug;Park, Byoung-Woo
    • The Journal of the Korea Contents Association
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    • v.7 no.11
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    • pp.76-83
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    • 2007
  • In the sequentially rotated array antennas, the characteristics of antenna gain, axial ratio and cross polarization have been analyzed with a varying of sequential array constant(number of array element, figure of rotation) respectively. Where the antenna element of array is a probe feeding, LHCP truncated microstrip antenna whose resonant frequency is in 11.85GHz. The simulation results of 23 SRA antennas((M=2, 3, 4, 6, 8), $(1\leqP\leqM)$) has shown as follows. The widest 3dB bandwidth of axial ratio appears at P=2 which is in-dependant of M, the highest antenna gain appears when a sequential array constant has a pair of (2, 1), (3, 2), (4, 1), (6, 3), (8, 1) respectively. Specially, all of the SRA antenna appear very poor characteristics in case of M=P. Therefore the SRA antenna has to be designed as selecting a optimal sequential array constant among a lot of simulation data.

Ka-band Microstrip Antenna Fed Circular Polarized Horn Array Antenna Design (평판형 안테나 급전구조를 이용한 원형편파용 도파관 배열안테나 설계)

  • Jung, Young-Bae
    • Journal of IKEEE
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    • v.17 no.2
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    • pp.140-144
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    • 2013
  • This paper presents the novel design of circular polarized Ka-band horn array antenna. The element antenna of the arrya is composed of two parts, microstrip patch and square horn, and the microstrip patch is fed by corner truncated microstrip patch for circular polarization. The patch antenna has the role of a feeder and polarizer of the horn, thus the whole size of the horn antennae can be considerably reduced. The $1{\times}8$ horn array was designed and fabricated by the spacing of $0.9{\lambda}_0$ among the element horn. The element horn has typical gain of 8dBi and axial-ratio bandwidth of 4.9% at 3dB, and the minimum gain and axial-ratio bandwithd of the array is 14dBi and 8.2%.

Design of S-band Turnstile Antenna Using the Parasitic Monopole (기생 모노폴을 이용한 S-band Turnstile 안테나 설계)

  • Lee, Jung-Su;Oh, Chi-Wook;Seo, Gyu-Jae;Oh, Seung-Han
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.11 s.114
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    • pp.1082-1088
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    • 2006
  • A turnstile antenna using the parasitic monopole has been developed for STSAT-2 TT&C application. The antenna consists of two radiating elements; a bow-tie dipole and a parasitic monopole. The bow-tie dipole is main radiating element, used a bow-tie structure for bandwidth improvement and size reduction. The parasitic monopole improved beamwidth and axial ratio. The input impedance of the antenna is about 50 ohm without a matching circuit. The proposed antenna has beamwidth of $>140^{\circ}$, axial ratio of < 3 dB and VSWR of < 1.5 in the band of $2.075{\sim}2.282GHz$.