• Title/Summary/Keyword: Microstrip Antenna

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Matching Network Design for Improving the Bandwidth of Microstrip Antenna (마이크로스트립 안테나의 대역폭 개선을 위한 정합회로설계)

  • 전성근;이종룡;이우재;이문수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.3
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    • pp.305-316
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    • 1998
  • The impedance matching network with the simplfied real frequency technique (SRFT) is proposed as a method for bandwidth enhancement of microstrip antenna. The validity of the technique is based on the relative frequency insensitivity of the radiation pattern and gain characteristics as compared to the resonant behaviour of the input impedance. The most significant feature of this technique is that there is no need to find any analytical description of the antenna and generator, and it only utilizes directly real frequency generator and load data over the prescribed frequency band. Furthermore, it is not necessary to invent an analytic form of the system transfer function to assume a matching network topology in advance. In this paper, the transmission line model is used to investigate the rectangular microstrip antenna, and based on the Fano's bandwidth-enlargement theory, the SRFT is introduced to design the matching networks of microstrip antennas in order to obtain a constant gain over the frequency band of interest. Two representative microstrip antnnas with different structure are fabricated and tested. From these procedures, it is obtained that the proposed impedance matching networks of microstrip antenna improve the impedance bandwidth nearly three times compared to the antenna without them.

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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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    • 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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A Study on Aperture Coupled U-slot Microstrip Antenna using Wideband Stub (광대역 Stub를 이용한 개구 결합 급전 방식의 U 슬롯 마이크로스트립 안테나에 관한 연구)

  • 김현준;윤영중
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.4
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    • pp.342-350
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    • 2002
  • In this paper, aperture coupled U-slot microstrip antenna with wideband stub is investigated. The dielectric constant of the substrate is 2.2 and the hight of the substrate is 62 mil. The impedance bandwidth (VSWR<1.5) of U-slot antenna with wideband stub is about 10 %. The bandwidth characteristic of U-slot antenna wish wideband stub is compared with that of antenna without it. And the results of parameter studies of the wideband stub provides the optimum characteristics of bandwidth and matching.

Cavity-Backed Microstrip Antenna for a Monopulse Radar (모노펄스 레이다용 Cavity-Backed 마이크로스트립 안테나 개발)

  • 박종국;나형기;구연덕;이종민
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.2
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    • pp.96-103
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    • 2003
  • A cavity-backed microstrip patch antenna for a monopulse radar system is designed and fabricated. Also, this antenna is shown to be suitable for the system by analyzing the measured results. Since the azimuthal beamwidth required by this system is quite broad compared to that of a usual microstrip antenna, the width of a microstrip patch is reduced considerably. The decrease of an antenna bandwidth due to the reduced patch width is compensated by increasing the effective substrate thickness. A detection range and a detection probability is calculated from the measured gain at a given angle, and this result shows that the fabricated antenna can be applied well to this monopulse radar system.

Wideband Slot-Coupled Microstrip Antenna with The Reflector (반사판을 갖는 슬롯 결합 급전을 이용한 광대역 마이크로스트립 안테나)

  • Kim, On;Kim, Gun-Kyun;Rhee, Seung-Yeop
    • The Journal of the Korea institute of electronic communication sciences
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    • v.14 no.6
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    • pp.1045-1052
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    • 2019
  • In this paper, the slot-coupled microstrip antenna structure with reflector is used for broadband. The reflector of this structure is designed to reduce the radiation emitted from the slot and minimize the influence of external electromagnetic environment while reducing the overall antenna height. Experimental results show that the antenna is very well matched with VSWR below 1.4 at 1.942.17GHz, and the maximum gain of the antenna in this band was measured 9.21dBi. The measured results shows that it can be used in the wireless communication field or IoT field of other frequency band in the future.

Wideband Microstrip Antenna with the Double U-slots (이중 U-슬롯을 이용한 광대역 마이크로스트립 안테나)

  • 오은실;윤영중
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.7B
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    • pp.727-736
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    • 2002
  • In this paper, the broadband microstrip antenna with small size, thin-profile, conformability and ease of manufacture is proposed for providing PCS(down link: 1.75GHz∼1.78GHz, up link: 1.84GHz∼1.87GHz) '||'&'||' IMT-2000(down link: 1.92GHz∼1.98GHz, up link: 2.11GHz∼2.17GHz) services simultaneously. By using double U-slots and matching stub, the bandwidth and operating performance of printed antenna was significantly improved, with need for a complex fabrication procedure. We have also studied the various parameters of the U-slot$_2$for the performances of the antenna. Impedance bandwidth of the wideband microstrip antenna with the double U-slots is about 30.45% (VSWR<2)

Design of Microstrip Antenna with U Slotted Ground Plane using Genetic Algorithm and FDTD Method (유전자 알고리즘과 FDTD 방법을 이용한 접지면 U 슬롯 구조의 마이크로스트립 안테나 설계)

  • 임현준;윤현보
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.2
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    • pp.194-198
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    • 2004
  • This paper presents a broadband compact microstrip antenna design with four U slots on the ground plane by using of genetic algorithm. FDTD method is used as fitness function for antenna analysis, and length of rectangular patch, length of ground plane slot, distance from center point to feed point is used as optimization parameter for maximum bandwidth and minimum size. The measurement result of implemented antenna present 10 dB bandwidth of 15.63 % and peak gain of 3.61 dBi in the 2.445 GHz, and antenna has a reduced patch size of 54.8 % compare with normal microstrip antenna.

A Study on the Fabrication of Microstrip Array Antenna for Koreasat Reception (무궁화 위성방송 수신용 마이크로스트립 어레이 안테나 제작에 관한 연구)

  • 전주성;이윤현
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.4
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    • pp.544-552
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    • 2000
  • In this paper, the microstrip antenna is studied to replace the parabolic antenna in the DBS reception. It is expected that the good picture quality DBS reception will be possible with this antenna irrespective of rain attenuation for the 99.9% time in a monthly average since the C/N ratio f 19dB is proved by the reception experiment of a Koreasat with fabricated antenna. From the results of this paper, it is shown that the electrical characteristics of the microstrip antenna can be improved to the level similar to that of the parabolic antenna. Hence, it is considered that the fabricated microstrip antenna can replace the parabolic antenna in DBS service coverage.

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Broadband polarimetric Microstrip Antennas for Space-borne SAR

  • Hong, Lei;Qunying, Zhang;Guang, Fu
    • Proceedings of the KSRS Conference
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    • pp.465-470
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    • 2002
  • A novel phased array antenna system for space-borne polarimetric SAR is proposed and completed in this paper.The antenna system assures polarimetric and multi-mode capability of SAR. It has broadband, high polarization isolation and high port to port isolation. The antenna system is composed of broadband polarimetric microstrip antenna, T/R modules and multifunction beam controller nit. The polarimetric microstrip antenna has more than 100MHz bandwidth at L-band with -30dB polarization isolation and high port to port isolation. The microstrip element and T/R module's structure and characteristics, the subarray's performances measuring results are presented in detail in this paper. A design scheme on beam controller of the phased array antenna is also proposed and completed, which is based on Digital Signal Processing (DSP) chip -TMS320F206. This beam controller unit has small size and high reliability compared with general beam controller. In addition, the multifunction beam controller unit can acquire and then send the T/R module's working states to detection system in real time.

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Design and Implementation of A Microstrip Antenna for Satellite-DMB (위성 DMB용 마이크로스트립 안테나 설계 및 제작)

  • Ahn, Je-Sung;Seo, Yu-Jung;Ha, Deock-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.856-860
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    • 2007
  • In this paper, we propose a microstrip antenna with sufficient impedance bandwidths and gains for the 2.65GHz antenna which used in the satellite digital multimedia broadcasting. The proposed 2.65GHz S-DMB bandwidth microstrip antenna on a substrate, which is small enough to be installed in practical mobile phones, and described simulation feature using by CST Microwave Studio program. The measured result is similar with commercial antenna and acceptable frequency band is found that more wide than the existing products.

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