• Title/Summary/Keyword: LPDA

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Design of a Compact LPDA Antenna using Inverted-L Shaped Dipole Elements (Inverted-L 형태의 다이폴 소자를 이용한 소형 LPDA 안테나 설계)

  • Yeo, Jun-Ho;Lee, Jong-Ig
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.7A
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    • pp.678-682
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    • 2011
  • In this paper, a compact log periodic dipole array (LPDA) antenna operating from 1 to 6 GHz is studied. Inverted-L shaped dipole elements are used to miniaturize the lateral size of an LPDA antenna and the spacing factor is also decreased to reduce the total length of the LPDA antenna. As the top-loading length of the inverted-L shaped dipole elements is increased, the width of the LPDA antenna is decreased but the bandwidth and the gain of the antenna are decreased. The fabricated compact LPDA antenna is printed on FR4 substrate With a dielectric constant of 4.4 and a thickness of 1.6 mm, and its size is reduced to 32% in width and 49% in length compared to a standard LPDA antenna.

A Study on Miniaturization of a Log-Periodic Dipole Array Antenna (대수주기 다이폴 배열 안테나의 소형화 연구)

  • Ham, Hyung-Jun;Ryu, Hong-Kyun;Park, Beom-Jun;Park, Young-Ju;Lee, Kyu-Song;Woo, Jong-Myoung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.7
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    • pp.709-720
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    • 2014
  • In this paper, we studied miniaturization of LPDA(Log-Periodic Dipole Array) antenna used for VHF and UHF bands. To miniaturize the LPDA antenna, in this study, the radiation elements in a low frequency were changed into a triangular meander structure which has small current cancelation effect at feed part. For the triangular meander structure, an isosceles triangular and right triangular meander structures were proposed and the LPDA antennas were miniaturized by using the two meander structures. Also, the simulated and measured results were compared for the two miniaturized LPDA antennas. As a result, the isosceles triangular meander and right angle triangular meander structure applied LPDA antennas were reduced up to 60.5 % and 72.4 % compared a basic LPDA antenna, respectively. Consequently, we confirmed that the triangular meander structure is suitable for miniaturization of a LPDA antenna.

Compact UWB Log Periodic Right Triangle-Shaped Dipole Array Antenna Appended With Strips (스트립이 추가된 소형 UWB 대수 주기 직각 삼각형-모양 다이폴 배열 안테나)

  • Yeo, Junho;Lee, Jong-Ig
    • Journal of Advanced Navigation Technology
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    • v.26 no.5
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    • pp.344-349
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    • 2022
  • A compact LPDA antenna consisting of right triangle-shaped dipole elements appended with strips is proposed for UWB applications. First, right triangle-shaped dipole elements are used instead of conventional strip dipole elements to reduce the width of the LPDA antenna. Second, the spacing between the LPDA elements is decreased to reduce the length of the LPDA antenna. Finally, strips are appended at the ends of the right triangle-shaped dipole elements in order to further reduce the width of the antenna. A prototype of the proposed antenna with 16 elements and gain > 4 dBi is fabricated on an FR4 substrate with dimensions of 44 mm×30 mm. Measured frequency band of the fabricated antenna is 2.99-14.76 GHz for a VSWR < 2, which ensures UWB operation, and measured gain range is 4.0-5.5 dBi with a front-to-back ratio larger than 10 dB. The length and width of the proposed compact LPDA antenna are reduced by 40.9% and 20.6%, respectively, compared to the conventional LPDA.

Miniaturization of Log-Periodic Dipole Array Antenna for PS-LTE Service (재난안전 통신망 서비스를 위한 대수 주기 다이폴 배열 안테나의 소형화)

  • Jeon, Hoo-Dong;Heo, Soo-Young;Ko, Ji-Hwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.3
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    • pp.170-176
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    • 2017
  • In this paper, we proposed the miniaturized structure of the Log-Periodic Dipole Array(LPDA) antenna for PS-LTE(Pubic Safety-Long Term Evolution) service. The length of array dipole was shortened by adding a fractal tree element with iteration to the array dipole to miniaturize the LPDA antenna. As the result, the proposed LPDA antenna was reduced up to 25 %, compared a typical LPDA antenna. To validation of the proposed LPDA antenna specification, the proposed LPDA antenna is fabricated using aluminum with 1.5 mm thickness and performances are measured. Comparison between simulation result and experiment shows good agreement.

Analysis of Log-Periodic Dipole Antennas above Lossy Grounds (손실이 있는 대지 위의 대수주기 다이폴 안테나 해석)

  • 최학근
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.1
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    • pp.109-121
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    • 1999
  • In this paper, HF band LPDA(Log-periodic Dipole Antenna) and MLPDA(Modified Log-periodic Dipole Antenna) above lossy grounds were analyzed using moment method by considering the practical media parameter of lossy grounds, not assuming free space or perfect ground approximation. The radiation pattern and gain of LPDA and MLPDA as functions of frequency, antenna height from ground, and antenna tilt angle are presented, and the lossy ground effect on antennas characteristics are described. MLPDA was found to exhibit a smaller variation for gain and radiation pattern and a higher maximum beam direction relative to LPDA. It was shown that media parameter of lossy grounds and antenna height have a direct influence on the antenna gain of both LPDA and MLPDA.

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Miniaturized LPDA Antenna for Portable Direction Finding Applications

  • Yeo, Jun-Ho;Lee, Jong-Ig
    • ETRI Journal
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    • v.34 no.1
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    • pp.118-121
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    • 2012
  • In this letter, a miniaturized log-periodic dipole array (LPDA) antenna operating from 1 GHz to 6 GHz is proposed for portable direction finding applications. To reduce the lateral size of an LPDA antenna, bow-tie elements and a top-loading technique are utilized and spacing factor is decreased to reduce the spacing between the LPDA elements. The proposed miniaturized LPDA antenna has the measured gain and front-to-back ratio ranging from 1.2 dBi to 3 dBi and from 7 dB to 22 dB, respectively.

Analysis and Characteristics of Log-Periodic X Dipole Antennas (대수주기 X 다이폴 안테나의 해석 및 특성)

  • 최학근
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.3
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    • pp.329-339
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    • 1999
  • LPXDA(Log-Periodic X Dipole Antenna), consisting of X dipole elements, was proposed as a Log-periodic antenna with short boom length and good Performance relative to LPDA(Log-Periodic Dipole Antenna) . LPXDA for operating frequency band of 500 MHz~l,000 MHz was designed and radiation characteristics of the designed antenna was analyzed by moment method, and compared with LPDA characteristics. The proposed LPXDA, in this paper, was found to have shorter boom length by 20% and better radiation characteristics with variations of frequency relative to the LPDA. The calculated results show good agreement with measurements.

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Radiation Characteristics of Log-Periodic Bent Dipole Antennas (대수주기 벤트 다이폴 안테나의 복사특성)

  • 최학근;김선표;임성빈
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.11
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    • pp.1207-1215
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    • 2003
  • In this paper Log-Periodic Bent Dipole Antenna(LPBDA), which is composed of bent dipole elements instead of dipole elements, is proposed to reduce the size of Log-Periodic Dipole Antenna(LPDA). LPBDA for the operating frequency band of 1 ㎓∼3 ㎓ is designed and its radiation characteristics are analyzed by the moment method, and compared with radiation characteristics of LPDA. It is shown that although LPBDA decreases in size by about 20 %, radiation characteristics of LPBDA are similar to radiation characteristics of LPDA. Calculated results show good agreement with measured results.

Design of an Ultra-Wideband LPDA Antenna for the Feeder of an Airborne Spinning Direction-Finding Reflector Antenna (공중 회전 방향탐지 반사판 안테나 급전기용 초광대역 LPDA 안테나 설계)

  • Park, Young-Ju;Park, Dong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.7
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    • pp.653-659
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    • 2016
  • This paper proposes an ultra-wideband Log-Periodic Dipole Array(LPDA) antenna for the feeder of a reflector antenna to be used for airborne spinning direction-finding and detecting wideband signals. To obtain the ultra-wideband characteristics over the 20:1 bandwidth from S to Ka band, the radiation elements of the antenna were printed on a substrate and a wedge-typed dielectric supporter with robust structure was inserted between the substrates. Also, the center portion of the supporter was replaced by a styrofoam material to reduce the supporter weight. The 5-dB return loss of the designed LPDA antenna showed ultra-wideband characteristics, which are 37.57:1(1.09~40.95 GHz) in the simulation and 33.85:1(1.31~44.35 GHz) in the measurement. We achieved the required gains of 5.78 dBi in the simulation and 5.76 dBi in the measurement in the operating band. The proposed robust, light-weight, and ultra-wideband LPDA antenna confirmed that it can be applied for airborne applications.

Log-Periodic Bow-tie Dipole Array(LPBDA) Antenna for UWB Communications (UWB 통신용 대수 주기 보우타이 다이폴 배열 안테나)

  • Yeo, Jun-Ho;Lee, Jong-Ig
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.9
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    • pp.4095-4100
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    • 2011
  • In this paper, a log periodic bow-tie dipole array (LPBDA) antenna for UWB communications is investigated. Bow-tie shaped dipole elements are used instead of general dipole elements for LPDA antennas and the input reflection coefficient and realized gain characteristics of the LPBDA as a function of a flare angle are analyzed. It turns out that as the flare angle of the bow-tie dipole elements is increased, the lowest operating frequency is shifted toward lower frequency and the operating frequency band is increased, but the average gain is decreased. However, the gain variation of the LPBDA is much decreased and the front-back ratio is improved compared to the LPDA. Standard LPDA and LPBDA with a flare angle of 13 degrees are fabricated on an FR4 substrate with a dielectric constant of 4.4 and a thickness of 1.6 mm. Measured gain for the LPDA ranges from 4 to 6.5 dBi at 3.1 to 10.6 GHz band, while that for the LPBDA is in the range of 4.2 to 5 dBi.