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Tunable-Slot-Type Ground Radiation Antenna with Dual Band Operation Using LC Resonator
Zeeshan Zahid,Hyeongdong Kim 한국전자파학회JEES 2017 Journal of Electromagnetic Engineering and Science Vol.17 No.2
A dual-band tunable-slot-type ground radiation antenna is proposed. The feeding structure consists of a coplanar waveguide and a lumped capacitor to excite currents for first- and second-order resonant modes of the ground. The resonant frequencies of both bands are controlled using a series combination of a capacitor and an inductor. The proposed design may be an attractive choice for mobile devices owing to its compact geometry and tunable operating frequencies. The measurement and simulation results of the proposed antenna show good agreement, indicating good impedance matching and radiation performance.
Loop-type ground radiation antenna for a discontinuous square ring-shaped ground plane
Zahid, Zeeshan,Kim, Hyeongdong IET 2017 Electronics letters Vol.53 No.12
<P>A loop-type ground radiation antenna is proposed for a discontinuous square ring-shaped ground plane. The antenna shows strong coupling with the ground mode if it is located at the maximum current density location. The location of the antenna has been evaluated using characteristic mode analysis of the currents on the ground plane. The size of the loop-type ground radiation antenna is 10 × 4.5 mm and it is fabricated on a square ring-shaped ground plane of size 50 × 50 mm having a gap of 2 mm. The design is intended for mobile device applications operating at 2.45 GHz.</P>
Circular Polarization Dielectric Resonator Antenna Excited by Single Loop Feed
Sinhyung Jeon,Hyengcheul Choi,Hyeongdong Kim 한국전자통신연구원 2009 ETRI Journal Vol.31 No.1
A new feeding method for the circular polarization (CP) dielectric resonator antenna (DRA) is proposed in this letter. Two orthogonal modes (TExδ11, TEy1δ1) of the rectangular DRA are excited by a 90-degree phase difference of the differential and common modes currents of the proposed feeding structure. To demonstrate the good CP performance of the proposed method, a right-hand CP DRA for a global positioning system was designed. The impedance bandwidth of the proposed antenna for S11<-10 dB and 3 dB axial ratio bandwidth are about 5.4% and 1.95% at 1.57 GHz, respectively.
Mobile Antenna Using Multi-Resonance Feed Structure for Wideband Operation
Jaesuk Lee,Yang Liu,Hyeongdong Kim IEEE 2014 IEEE transactions on antennas and propagation Vol.62 No.11
<P>A multi-resonance feed structure for exciting a mobile handset antenna in order to achieve multiband operation is presented. The feed structure adjusts its impedance and controls the coupling with the antenna structure. Based on the proposed feed structure, the dimensions allowed for the antenna design are only 10 × 55 × 2 mm <SUP>3</SUP> while the measured impedance bandwidth is from 694 to 1003 MHz in the lower band and from 1656 to 2772 MHz in the higher band under a voltage standing wave ratio of 3:1 with good measured realized efficiency. The proposed antenna is a competitive candidate that fully covers most 4th generation (4G) and existing wireless communication services.</P>
Effect of capacitor position on radiation patterns of ground radiation antenna
Rui Zhang,Yang Liu,Hyeongdong Kim IET 2015 Electronics letters Vol.51 No.23
<P>The radiation-pattern variations of a ground radiation antenna are investigated. The series capacitor connected in the antenna radiation loop is successively placed in two different positions while the radiation patterns are respectively observed. The simulation and experimental results indicate that the radiation patterns are significantly changed in accordance with the capacitor's position. This study can be applied to implementing a radiation-pattern-reconfigurable GPS antenna.</P>
Design of a Dual-Band Chip Antenna Using a Gap-Fed Branch
CHOI, Hyengcheul,KIM, Hyeongdong The Institute of Electronics, Information and Comm 2009 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.92 No.8
<P>Dual-band chip antennas usually have a narrow bandwidth in the first resonance frequency band due to an inter-coupling capacitance. In order to analyze the effect of the inter-coupling capacitance, an equivalent circuit of an antenna with a branch radiator is considered in this paper. Based on the equivalent circuit model, it is found that the inter-coupling capacitance reduces impedance bandwidth. This paper proposes a gap feeding method to alleviate the effect of the inter-coupling capacitance and explains it using an equivalent circuit.</P>
그라운드 모드의 공진을 이용한 광대역 격리도를 가지는 스마트 안경용 소형 MIMO 안테나
유종인(Jongin Ryu),김형동(Hyeongdong Kim) 한국전자파학회 2018 한국전자파학회논문지 Vol.29 No.10
본 논문에서는 스마트 안경에서 사용가능한 2.4 GHz 무선 근거리 통신망(WLAN) 대역용 소형 다중 입력 다중 출력(MIMO) 안테나 설계 및 구현에 대한 제안을 하였다. MIMO 안테나 시스템을 소형화하기 위해서, 안테나의 그라운드면을 방사체로서 사용하였으며, T 자형의 접지면을 제안하고 있다. 광대역 격리를 특성을 확보하기 위해, 이중 공진이 그라운드 모드에서 형성되도록 한다. 하나의 공진은 T 자형 접지에 의해 생성되고, 두 번째 공진은 두 개의 급전선 사이에 슬롯과 커패시터를 추가하여 만들어진다. 구현된 안테나의 측정 결과, 반사 계수 특성은 -5.1 dB보다 작지만, 얻는 격리 특성은 −20 dB 미만이다. 다이버시티 성능은 측정된 2차원 방사 패턴을 사용하여 평가하였고, 목표 대역(2.4~2.5 GHz)에서 측정된 ECC(envelope correlation coefficients) 값은 0.1 미만이다. In this letter, a compact multiple-input multiple-output(MIMO) antenna design for a 2.4 GHz wireless local area network(WLAN) band is proposed for use in smart glasses. To miniaturize the MIMO antenna system, a ground plane is employed within the antenna and a T-shaped ground is proposed. To achieve wideband isolation, dual resonance is formed by the ground mode. One resonance is created by the T-shaped ground and the second resonance is created by adding a slot and a capacitor between the two feed lines. The measurements show that the reflection coefficient characteristic was less than -5.1 dB, whereas the isolation obtained was less than -20 dB. The diversity performance was evaluated using the measured two-dimensional radiation patterns, and the envelope correlation coefficient(ECC) values achieved in the target band(2.4~2.5 GHz) were less than 0.1.
Analysis of a loop type ground radiation antenna based on equivalent circuit model
Zahid, Zeeshan,Kim, Hyeongdong IET 2017 IET microwaves, antennas & propagation Vol.11 No.1
<P>A loop type ground radiation antenna has been analysed using an equivalent circuit model in this study. The proposed circuit model has been selected in such a way that the design parameters of the ground radiation antenna can be mapped onto the circuit. To demonstrate the accuracy of the model, a specific ground radiation antenna is designed in a full wave electromagnetic simulator and the equivalent circuit model of the antenna is optimised in a circuit simulator. The simulation results of the circuit simulator and full wave simulator are compared. Expressions of return loss and input impedance of the equivalent model have also been obtained. The proposed circuit model can be used to develop insight and describe the behaviour of the network parameters of the antenna.</P>
Dual-band chip antenna design using intercoupling capacitance
Choi, Hyengcheul,Kim, Hyeongdong Wiley Subscription Services, Inc., A Wiley Company 2009 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.51 No.6
<P>For the dual-band (GSM/DCS) operation, the second-order resonance is used to operate in the high frequency range. To control the bandwidth characteristics in each band, an intercoupling capacitance between the radiating elements is utilized to satisfy the bandwidth requirements of GSM (890–960 MHz) and DCS (1710–1880 MHz) cellular communications systems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1467–1470, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24374</P>
후면 그라운드를 이용한 휴대단말 Wi-Fi 칩 안테나 설계
오세원(Saewon Oh),김형동(Hyeongdong Kim) 한국전자파학회 2012 한국전자파학회논문지 Vol.23 No.5
본 논문에서는 휴대단말기의 Wi-Fi 대역에서 동작하는 소형 칩 안테나를 설계하였다. 제안된 안테나의 소형화를 위해 칩 안테나 하단에 후면 그라운드를 갖도록 설계하였다. 제안된 안테나는 S자 모양 대칭형으로 유전율이 3.5인 LCP(Liquid Crystal Polymer) 위에 설계되었으며, 칩 안테나의 전체 크기는 6.0 mm×2.5 mm×1.2 mm를 갖는다. 제작된 안테나는 VSWR=3 이하 기준 300 MHz(fractional bandwidth: 12.2 %, 2.3~2.6 GHz)의 임피던스 대역폭과 peak gain은 1.42 dBi의 특성을 나타냈다. 안테나 설계는 CST Microwave Studio 상용 프로그램을 사용하여 최적화한 후, 설계된 안테나를 제작하고, 네트워크 분석기와 무반향실을 이용하여 측정하였다. In this paper, a new small chip antenna for Wi-Fi application of the mobile handset is proposed. To miniaturize the chip antenna, the proposed antenna is designed to have the backside ground. The proposed antenna has S-shaped structure, which is designed on the LCP(Liquid Crystal Polymer) with εr =3.5. The size of the proposed antenna is 6.0 mm×2.5 mm×1.2 mm. The measured impedance bandwidth under a voltage standing wave ratio (VSWR) of 2 was 300 MHz(fractional bandwidth: 12.2 % 2.3~2.6 GHz), and peak gain is 1.42 dBi. The proposed antenna was designed using CST Microwave Studio commercial software tool. And the fabricated antenna is measured using a network analyzer and in anechoic chamber.