• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.768-772
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• 2007

Integration of RF front end module(FEM) into the antenna has been investigated in USPCS band (1.88GHz-1.99GHz). The FEM consists of input filter, power amplifier, coupler, power detector, bias switch and duplexer. The antenna was designed in planar inverted F antenna(PIFA) structure to implement it inside the handset. In order to avoid strong coupling between the antenna and FEM, a shielding ground layer was placed between them. The antenna size is 19mm by 10mm by 6mm under which FEM whose size is 8mm by 5mm by 1.5m locates. The antenna impedance was selected to match to FEM having better efficiency rather than gain since FEM has enough gain whose system spec is minimum of 20dB. The antenna patterns are shown with and without FEM.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.306-310
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• 2000

본 논문에서는 안테나 구조해 따른 PCS 전화기에 의해 인체두부에 유기되는 SAR 값을 비교 분석하였고, SAR 값에 영향들 주는 요인을 분석하였다. 안테나의 종류, 안테나의 부착위치, 단말기의 구조에 따른 1 g 및 10 g 평균 첨두 SAR 값을 계산하였고, 인체 두부의 깊이에 따른 SAR 분포의 변화를 살펴보았다. 플립형 단말기에 부착된 안테나 중에서는 side mounted PIFA(Planar Inverted F Antenna)의 1 g 및 10 g 평균 첨두 SAR 값이 각각 0.686 W/kg과 0.353 W/kg으로 가장 낮았다. 폴더형 단말기에 부착된 모노폴 안테나에 의한 1 g 및 10 g 평균 첨두 SAR값은 플립형에 의한 SAR 값에 비해 약 30 % 가량 낮은 것으로 나타났다. 평균 첨두 SAR 값이 낮은 값을 보이는 두 구조인 side mounted PIFA와 폴더형 구조의 모노폴 안테나의 깊이에 따른 SAR 분포는 나머지 두 구조에 비해 비교적 완만한 경사를 보였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.2
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• pp.56-61
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• 2008

Diversity antenna system against multi-fading environment is strongly required for WiBro service of vehicle. In general, high isolation performance between antennas leads to good diversity gain. In this paper, a polarization diversity antenna is presented, which has orthogonal polarizations and good isolation characteristic. In addition, by simulation and measurement, it is certified that HWLLA (Half Wave Length Loaded Antenna) improves polarization purity on common ground. In isolation between two antennas, HWLLA can provide better isolation over 12dB than conventional PIFA (Planar Inverted F Antenna).

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2291-2293
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• 2005

본 논문에서는 평면 역F 안테나(PIFA)형태의 단일 안테나로 2GHz 대역과 5GHz 대역의 무선 근거리통신망의 주파수 대역을 수용할 수 있는 안테나를 설계 제작하였다. 안테나의 크기를 줄이기 위해 안테나 Element는 Meander Line을 이용하여 설계하였다. 측정 시 반사손실 10dB(VSWR=2.0)를 기준으로 2GHz 대역에서 10.8%와 5GHz대역에서 12.7%의 대역폭을 얻었다.

• Journal of Power Electronics
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• v.17 no.2
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• pp.533-541
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• 2017

This paper presents a novel Parameter-Independent Fictive-Axis (PIFA) approach for the Voltage-Oriented Control (VOC) algorithm used in grid-tied single-phase inverters. VOC is based on the transformation of the single-phase grid current into the synchronous reference frame. As a result, an orthogonal current signal is needed. Traditionally, this signal has been obtained from fixed time delays, digital filters or a Hilbert transformation. Nevertheless, these solutions present stability and transient drawbacks. Recently, the Fictive Axis Emulation (FAE) VOC has emerged as an alternative for the generation of the quadrature current signal. FAE requires detailed information of the grid current filter along with its transfer function for signal creation. When the transfer function is not accurate, the direct and quadrature current components present steady-state oscillations as the fictive two-phase system becomes unbalanced. Moreover, the digital implementation of the transfer function imposes an additional computing burden on the VOC. The PIFA VOC presented in this paper, takes advantage of the reference current to create the required orthogonal current, which effectively eliminates the need for the filter transfer function. Moreover, the fictive signal amplitude and phase do not change with a frequency drift, which results in an increased reliability. This yields a fast, linear and stable system that can be installed without fine tuning. To demonstrate the good performance of the PIFA VOC, simulation and experimental results are presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.5
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• pp.21-26
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• 2014

This paper proposes a frequency reconfigurable antenna which operates at not only LTE but also other currently serviced bands. The high band(1,710-2,170 MHz) performance was satisfied through PIFA structure, and the low band performance through the additional RF Switch by changing the state between SW1 and SW2. When the RF switch is SW1 state, the operation bandwidth is 782-907 MHz (GSM), and 738-861 MHz (LTE) at OFF state. The proposed antenna has a omni-directional radiation pattern and measured peak gains were 0.04-4.68 dBi at the SW1 state and 0.92-1.53 dBi at the SW2 state, respectively. Judging from the results, proposed reconfigurable antenna is expected to be applied to LTE-Advanced mobile terminals since the antenna shows an outstanding performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.4
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• pp.374-383
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• 2013

This paper presents a design for improvement of isolation characteristics by the inserted stub structure on ground plane of a handy terminal which is composed of a main antenna and a sub antenna covered LTE bandwidth. In order to compensate for a resonance length of proposed antenna and to realize a high isolation characteristic, a pair of stub was inserted and located on ground plane that currents from two antennas were converged. A simulated isolation characteristic of antenna without stub at the LTE class 13 band was about -5 dB, but its characteristics of proposed antenna with two stubs at uplink(777~787 MHz) and downlink(746~756 MHz) of the LTE class 13 band were about -12 dB and -15 dB, respectively. An average gain of a fabricated antenna with two stubs was observed about -2 dBi above and it showed good results with comparison of business condition that the average gain of commercial handy terminal has to appear -4 dBi above. The measured S-parameter characteristics and radiation patterns showed a reasonable agreement with the simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1015-1022
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• 2007

In this paper, we proposed a wideband design of planar inverted-F antenna(PIFA) using two-layer, patches and modified ground structure. The antenna consists of two layer patches with common feed and modified ground plane to control resonance frequency and antenna input impedance. The measured bandwidth is 1,492 MHz(BW: 67.7 %, 1,457${\sim}2,949$ MHz) for VSWR<2, and 1,170 MHz(BW: 21 %, 4,970${\sim}$6,140 MHz) for VSWR<2.5. It covers service bands of DCS1800, DCS1900, UMTS(WCDMA), WiBro, WLAN(IEEE 802.11b), satellite DMB. WLAN(IEEE 802.11a) in Korea and radiation patterns shows constant figure with frequency change.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.21-26
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• 2010

This paper describes patch antenna design method of antenna high gain and broad bandwidth using cylindrical magneto material around feeding line. Strong current induction method applied combination to generate magnetic fields around feeding line for antenna high gain characteristic and principle of PIFA designed application for design of antenna broadband. In case of single CMM, gain increased 3.96 dB compare with the reference antenna gain however bandwidth characteristic not increased compare with the reference antenna. In case of dual CMM, gain improved about 10 dB compare with the reference antenna and -10 below bandwidth is 700 MHz(50 MHz~750 MHz) with this paper designed high gain characteristic.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.477-483
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• 2008

The paper introduces mobile handset multi-band chip antenna to be used on meander line PIFA structure and parasite patch. The proposed antenna uses an FR-4 substrate. The top layer is consist of meander lines PIFA structure to implement GSM900 and is connected with each rad and meander line on the via-hole for maximize space efficiency. The middle layer is designed with the signal line and gap to implement a DCS and PCS bands, the bottom layer which is added to a parasite patch on the ground can be show an adjust of frequency and impedance character by the connection of the radiators of middle layer and coupling. The fabricated antenna with the dimension of $28{\times}6{\times}4\;mm^3$. The ground plane a dimension of $45{\times}90\;mm$, designed by a commercial software CST simulator. The experimental results show that the bandwidth for(VSWR<3) is 90($875{\sim}965$) MHz in GSM900 band operation and 380($1,670{\sim}2,050$) MHz in DCS, PCS band operation. The maximum gains of antenna are 0.25 dBi, 3.65 dBi and 3.3 dBi at resonance frequencies and it has omni-directional pattern practically.