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Critical coupling of a planar inverted F-antenna using a ferrite sheet
Kim, Hojeong,Choi, Hyengcheul,Jeon, Sinhyung,Kim, Hyeongdong Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.52 No.2
<P>In this letter, a novel method that can achieve critical coupling in a planar inverted F-antenna of high height is proposed. Theproposed antenna can achieve critical coupling by attachment of a ferrite sheet without changing the size of the antenna or ground plane. A ferrite sheet is used to increase shunt inductance of the shorting pin loop. The proposed antenna is modeled by an equivalent circuit based on transmission line modeling. It has a very wide bandwidth of 16% for a voltage standing wave ratios <2. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 400–403, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24950</P>
Performance enhancement of mobile antenna by ground decomposition
Kim, Jihoon,Shin, Hyunwoong,Kim, Min‐,gi,Kim, Hyeongdong John Wiley Sons, Inc. 2018 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.60 No.12
<P><B>Abstract</B></P><P>We propose a ground decomposition method (GDM) to improve the performance of mobile antennas. In the GDM, overall ground impedance is analyzed as the combination of independent decomposed ground parts. In a proposed design, the overall ground mode resonance is tuned by adjusting the impedance of a flexible printed circuit board, which is decomposed according to GDM. This greatly improves the radiation performance, as verified through simulation and measurement. This proposed method is effective for mobile antenna design, and especially for actual devices that have very complicated ground configurations.</P>
휴대 단말기 그라운드 방사 안테나(GradiANT: Ground Radiation Antenna) 기술 소개
김지훈(Jihoon Kim),문성진(Sungjin Moon),김형동(Hyeongdong Kim) 한국전자파학회 2015 한국전자파학회논문지 Vol.26 No.11
최근 휴대 단말기 안테나의 소형화와 고성능화에 대한 요구가 증대되고 있다. 단말기의 그라운드는 좋은 방사체로, 이를 활용한 휴대 단말기 그라운드 방사 안테나는 안테나의 소형화 및 고성능화를 동시에 만족시킬 수 있기 때문에, 많은 관심을 받고 있다. 그라운드 방사 안테나는 단말기 그라운드의 특성 모드를 제어하고, 이를 안테나와 결합하여 그라운드를 방사체로 활용하기 때문에 그 방사 성능이 우수하다. 본 논문에서는 그라운드의 특성 모드 이론에 대해 설명하고, 이를 활용한 그라운드 방사 안테나의 다양한 적용 예시를 단일 대역, 광대역 및 이중 대역 그라운드 방사 안테나로 나누어 소개하고자 한다. Ground radiation antenna in mobile devices is becoming an issue for satisfying both miniaturization and high performance. Ground radiation antenna controls the characteristic mode of the ground plane and couples this mode with the ground radiation antenna, thereby having good radiation performance. In this paper, the characteristic mode theory and applications of ground radiation antenna will be introduced. The operating mechanism of single band, wideband and dual-band ground radiation antennas are studied.
커패시터 구조를 급전 루프에 삽입한 광대역 PIFA 안테나 설계
김승우(Seungwoo Kim),박상규(Sang-Gyu Park),김형동(Hyeongdong Kim) 한국전자파학회 2010 한국전자파학회논문지 Vol.21 No.10
본 논문에서는 PIFA의 급전점과 단락점을 둘러싸는 급전 루프 내부에 커패시터 구조를 삽입하는 새로운 타입의 4중 대역(GSM900/DCS/PCS/W-CDMA) PIFA 설계를 제안한다. 커패시터의 삽입을 통해서 병렬 공진점인 2.01 ㎓에서의 반사 계수 ?2.73 ㏈를 ?6.26 ㏈로 낮추는 효과를 얻을 수 있었다. 병렬 공진에서의 좋지 못한 방사 특성을 개선시킴으로써 고차 대역(DCS/PCS/W-CDMA)에서의 광대역 특성을 나타내었다. This paper proposes a new type of PIFA with a capacitor structure inserted into the feeding loop. It operates in GSM900, DCS, PCS, and W-CDMA frequency bands. By inserting the capacitor, it shows the effect of lowering the return loss from ?2.73 ㏈ to ?6.26 ㏈ at the parallel frequency, 2.01 ㎓. The improvement of the poor radiation property near the parallel resonance frequency leads to a broadband operation in the upper band, DCS, PCS, and W-CDMA.
Antenna design using speaker wire for a Bluetooth ear set
Zahid, Zeeshan,Lee, Hongkoo,Kim, Mingi,Kim, Hyung‐,Hoon,Kim, Hyeongdong John Wiley Sons, Inc. 2019 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.61 No.3
<P><B>Abstract</B></P><P>In this article, an antenna design using an audio wire is proposed for a compact Bluetooth ear set. The length of the audio wire is less than a quarter of a wavelength in Bluetooth ear sets. Therefore, an appropriate feed structure needs to be designed to utilize the wire as an antenna. The antenna has been tuned using an inductor and impedance matching is accomplished by a loop‐type feeding structure with lumped capacitors. The feeding structure can be used to tune various lengths of the antenna. Full wave simulations are conducted to observe the effectiveness of the proposed technique. The measured and simulated bandwidths of the antenna are in good agreement. The measured bandwidth and average efficiency of the antenna were 116 MHz and 54.74%, whereas the average total isotropic sensitivity was 80.12 dBm that comply with the desired criteria for operation of the Bluetooth ear set.</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>
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>
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>