• Title, Summary, Keyword: Small antennas

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Small Antennas (소형 안테나)

  • Kim, Ki-Chai
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.3 no.2
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    • pp.79-83
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    • 1992
  • The demand for small and low-profile antennas has become quite strong, especially in mobile communications. This article presents an brief introduction to the fundsmental characteristics, design, and measurement of typical small antennas and low-profile antennas.

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Design of Small Antennas with Inductively Coupled Feed Using a Pareto Genetic Algorithm (Pareto 유전자 알고리즘을 이용한 초소형 유도결합 안테나 설계)

  • Cho Chihyun;Choo Hosung;Park Ikmo;Kim Youngkil
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.1
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    • pp.40-48
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    • 2005
  • In this paper, we explore the inductively coupled concept and propose a class of electrically small planar antennas. The antennas are optimized using NEC in conjunction with a Pareto GA. These antennas show good efficiency and bandwidth performance without any additional matching network. Several optimized designs are fabricated and measured. We explain the operating principle of these antennas using a simple lumped element circuit model. The proposed antennas are translated as printed lines on Duroid for RFID tag antennas.

Development of Ultra-Wideband Antennas

  • Chen, Zhi Ning
    • Journal of electromagnetic engineering and science
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    • v.13 no.2
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    • pp.63-72
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    • 2013
  • The ultra-wideband (UWB) spectrum available for commercial applications has offered us an opportunity to achieve high-speed wireless communications and high-accuracy location applications. As one of key research areas in UWB technology, a lot of innovative broadband and miniaturization techniques for UWB antennas have been greatly invented and developed for years. This paper reviews the development of UWB antenna design in the past decade. Starting with a brief introduction of the specific requirements and promising applications of UWB systems, the unique design challenges of UWB antennas are highlighted. Next, the important milestones of UWB antenna designs are briefed. After that, a variety of planar UWB antennas invented for broadband operation, miniaturization, and multiple functions are introduced. Last, the comments on the development of UWB antennas in future are shared.

A study of small antennas for MIMO applications (다중 입.출력(MIMO) 시스템용 소형 안테나 특성분석)

  • Chae, Gyoo-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.6
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    • pp.1194-1199
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    • 2006
  • In this paper, small printed antennas for MIMO applications are presented. The proposed antennas are based on PIFA structure which is a popular approach for miniaturization. The obtained antenna operates in IEEE802.11a band (5.15-5.35GHz) and has a planar structure which can be adopted for various potable applications. According to our simulation results, prototype antennas are manufactured and the isolation among the antenna elements are measured for MIMO applications. And we suggest a technique to improve isolation by adding a $\lambda$/4 slit between two antennas and investigate the results.

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Investigation of 3D Printed Electrically Small Folded Spherical Meander Wire Antenna

  • Kong, Myeongjun;Shin, Geonyeong;Lee, Su-Hyeon;Yoon, Ick-Jae
    • Journal of electromagnetic engineering and science
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    • v.17 no.4
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    • pp.228-232
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    • 2017
  • The radiation properties and fabrication precautions of a 3D printed, electrically small folded spherical meander wire monopole antenna are investigated. The antenna is self-resonant and shows sufficiently high radiation efficiency at an electrical size ka of 0.4, with the radiation quality factor Q approaching the lower physical bound. In antenna fabrication, the possible structural deformation due to gravity is examined before the antenna frame is 3D-printed. The required conductivity is achieved by multiple manual paintings of a silver paste. The radiation efficiency and pattern show very good agreement with the computed expectations, whereas the resonant frequency deviates by 11.8%. The method to minimize such a fabrication error when using 3D printing technology for wire antennas is discussed.

Worst-Case Estimate of Envelope Correlation Coefficient for Small MIMO Mobile Antennas Below 1 GHz

  • Zhao, Xing;Tak, Jinpil;Choi, Jaehoon
    • Journal of electromagnetic engineering and science
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    • v.15 no.1
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    • pp.44-52
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    • 2015
  • A worst-case estimate of an envelope correlation coefficient (ECC) is obtained for small multiple-input multiple-output (MIMO) mobile antennas operating below 1 GHz. The worst-case estimate is numerically derived in this paper using spherical and exponential wave functions. The derived result confirms that the worst-case ECC can be easily obtained from the rotation angle between the radiation patterns of two MIMO elements, which are attained directly from the amplitude of 2D electric field patterns without any additional phase and polarization information. As a practical example, MIMO mobile antennas with different antenna element arrangements are compared to verify the validity of the proposed worst-case estimate. Moreover, based on these analyses, we also suggest an effective approach to reduce the ECC of a small MIMO mobile antenna operating below 1 GHz by properly locating the antenna elements to make the radiation patterns perpendicular to each other.

A Small UHF RFID Key-Chain Tag Antenna for a Key-Management Metallic Cabinet with Consideration of Coupling of Adjacent Tags and Cabinet (태그간의 상호 간섭과 캐비닛의 간섭을 고려한 열쇠 관리용 캐비닛 안의 소형 UHF RFID 태그 안테나)

  • Nam, Sea-Hyeon;Park, Yong-Kwon;Jun, Byong-Don;Chung, You-Chung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.9
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    • pp.823-828
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    • 2009
  • A small UHF RFID tag antenna for a key-chain installed inside of a metallic key-management cabinet has been designed. The tag antenna has been designed as small size as $66\;mm{\times}6\;mm$ with consideration of coupling among the tag antennas and metallic parts of key-chain and cabinet. The tag antenna is fabricated with a meander line dipole using T-matching method with FR-4 substrate. One tag antenna has been designed with consideration of coupling of adjacent tag antennas, and the other has been designed for the location close to the metallic part in the cabinet. The characteristics of tag antennas and reading distance have been analyzed based on the different numbers of adjacent tag antennas. As a results, the 360 tag antennas installed in the cabinet have been successfully recognized.

The Impedance Characteristics of Verical Antennas Over a Finite Image Plane (영상면상의 직선형 안테나의 임피이던스 특성)

  • 양인용;조성호
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.3 no.3
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    • pp.2-13
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    • 1966
  • The impedance characteristics of vertical antennas over a finite image plane were analyzed and measured. Two kinds of image plane, one rectangular and the other circular, were used for the mesurements. And the length of antennas was varied at fixed frequency. All kinds of terminal zone effects which possible raise questions because of antenna mounting system were discussed. It is observed from the results that the measured impedance of antennas over a comparativley large rectangular plane is approximatly identical with the theoretical value, and also the impedance of antennas over a comparatively small circular plane had similar characteristics to a comparatively thick antennas over an inifinite image plane.

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Antenna Measurement on Cylindrical Surface in Fresnel Region Using Direct Far-Field Measurement System

  • Oh, Soon-Soo;Kim, Joung-Myoun;Yun, Jae-Hoon
    • ETRI Journal
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    • v.29 no.2
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    • pp.135-142
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    • 2007
  • The small anechoic chambers built by many small-/medium-sized companies and universities present difficulties in testing electrically large antennas because the chamber size cannot satisfy the far-field criterion of large antennas. In this paper, a method for Fresnel-region measurement on a cylindrical surface with variation of the measurement height is proposed and verified by both calculations and experiments. We implement the proposed method using a direct far-field measurement system by adding a few supporting structures. The results show good accuracy.

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Improvement of Performance of Thick High Dielectric Patch Antennas Using Photonic Bandgap Structures (포토닉 밴드갭 구조를 이용한 두껍고 큰 유전상수 패치 안테나의 성능 향상)

  • 기철식;박익모;이정일;임한조
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.91-95
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    • 2001
  • This paper presents that photonic bandgap structures suppressing the propagation of surface waves can improve the performance of the patch antennas on thick high dielectric constant substrate. The forbidden propagation of surface wave due to the photonic bandgap enhances the radiation efficiency and reduce the back radiation drastically with maintaining the small size and wide bandwidth of the antennas.

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