• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1037-1043
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• 2004

In this paper, a new fault detection and isolation algorithm fur inertial sensor system is proposed. To identify the inertial sensor fault, single antenna GPS receiver is used as an effective redundancy source. To use GPS receiver as redundancy for the inertial sensors, the algorithm to estimate the attitude and acceleration using single antenna GPS receiver is adopted. By using Doppler shift of carrier phase signal and kinetic characteristics of aircraft, attitude information of aircraft can be obtained at the coordinated flight condition. Based on this idea, fault diagnosis algorithm for inertial sensors using single antenna GPS based attitude is proposed. For more effective FDI, decision variables considering the aircraft maneuver are proposed. The effectiveness of the proposed algorithm is verified through the numerical simulations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.229-238
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• 2016

In this paper, we have studied isolation enhancement using a suppression of surface wave to improve performance of array antenna. To reduce isolation between elements of array antenna, perfect magnetic conductor(PMC) and SOFT-surface is designed and located at center of ground plane, isolation and gain is simulated by commercial full wave simulator(HFSS). As a result, isolation of more than 40 dB and gain improvement of 2.2 dBi are obtained at E-plane array in case of both PMC and SOFT-surface. At H-plane array, air coupling is dominant compared to coupling by surface wave. It is conclude that this study is useful for design of compact array antenna and performance improvement of array antenna.

• Journal of IKEEE
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• v.19 no.1
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• pp.18-26
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• 2015

In this paper, we proposed and evaluated the performance of an internal MIMO (Multiple Input Multiple Output) antenna for multiband operations including LTE (Long Term Evolution) 700/2300/2500. And to enhance the isolation characteristic, a parasitic element is designed and applied. The proposed single antenna has a volume of $60mm(W){\times}38mm(L)$, and the ground plane is $60mm(W){\times}100mm(L)$. The parasitic element used for enhancing the isolation of the antenna was designed with a copper on FR4 sized $60mm(W){\times}20mm(L){\times}1.6mm(H)$, and the pattern size is $60mm(W){\times}15mm(L)$. Simulated and measured results showed that LTE 700/2300/2500, DCS (Digital Cellular Service: 1710-1880MHz), K-PCS (Korea-Personal Communication Service: 1750-1870MHz), US-PCS (US-Personal Communication Service: 1850-1990MHz), WCDMA (Wideband Code Division Multiple Access: 1920-2170MHz), Wibro (2300-2390MHz), Bluetooth (2400-2483MHz), WLAN (Wireless Local Area Network: 2400-2483.5MHz), US-WiMAX (US-World interoperability for Microwave Access: 2400-2590MHz) frequency bands were covered with $S_{11}$ values less than -6dB (VSWR < 3). Simulated and measured results on $S_{21}$ at 730MHz for the firstly designed MIMO antenna showed -5.50dB and -5.65dB, respectively. When with the parasitic element at the separated ground plane to enhance the isolation performance, -10.33dB and -12.90dB are obtained for the simulation and measurement, so the enhanced isolation performance at lower frequency band (617-867MHz) is confirmed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.6
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• pp.57-62
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• 2012

In this paper, WCDMA indoor repeater antenna using an absorber based on metamaterial structure for high isolation is proposed. The proposed antenna consist of the main patch with the absorber based on metamaterial structure and parasitic patch. The WCDMA bandwidth is obtained by utilizing the coupling between the main and parasitic patches. The size of the absorber based on metamaterial structure is $13mm{\times}13mm$, the absorption is about 94 % at 2.18 GHz. The isolation characteristic of proposed WCDMA indoor repeater antenna between the service and donor antennas is improved by using a absorber based on metamaterial. The proposed WCDMA indoor repeater antenna has a gain higher than 6 dBi with a VSWR less than 2, and an isolation between the service and donor antennas greater than 85 dB over the WCDMA band from 1.92 GHz to 2.17 GHz. And size of the proposed antenna is $75mm{\times}75mm$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1058-1064
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• 2012

In this paper, an absorber based on metamaterial is proposed to improve the isolation of conventional WCDMA indoor repeater antenna. The proposed absorber is composed of Double Split Ring Resonators(DSRRs) and Complementary Spiral(CS) structure. The proposed absorber based on metamaterial is $9.6mm{\times}9.6mm{\times}1.2mm$ and absorption is about 94 % at 2.2875 GHz. The proposed antenna, which proposed absorber is applied to conventional WCDMA indoor repeater antenna, has isolation over 85 dB. Isolation is improved more than 10 dB compared with the conventional antenna. The VSWR is lower than 2 at WCDMA band from 1.92 GHz to 2.17 GHz. The radiation patterns are $60^{\circ}{\pm}10^{\circ}$ E-plane and H-plane, respectively. And, the gain is more than 6 dBi. The volume of proposed antenna with absorber based on metamaterial is $90mm{\times}90mm{\times}44.8mm$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.79-86
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• 2008

This paper presents to improve of isolation characteristics between personal communication service(PCS) antenna In mobile terminal and 2-channel multi input multi output(MIMO) antenna in the wireless broadband Internet(WiBro) band. In order to improve the isolation between each channel antenna, the proposed PCS antenna with an air space of 3 mm height is located on the projected ground plane($25{\times}12mm$) which is very small space$(0.19{\lambda})$ between the 2-channel WiBro-MIMO antenna. The proposed PCS antenna structure is a modified planar inverted F antenna (PIFA) of spiral type with shorting strip line(6${\times}$4 mm). The calculated Isolation values between the proposed PIFA with 3-dimensional structure and the MIMO antenna at Wibro band are about -20dB below and agree well with the measurement. Measured return loss, bandwidth, and gain o# the proposed antenna are -20dB at 1.8GHz, 110MHz(1.76${\sim}$1.87 GHz) band at -10dB below, and 0.05dBi, respectively, Moreover, we confirm that the proposed PCS antenna has no influence on performance and characteristics of the conversional 2-channel WiBro-MIMO antenna.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.79-84
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• 2011

In this paper we design MIMO antenna with high isolation between antennas by using an isolation aid for WLAN. Two dual-band PIFAs which operates IEEE 802.11n are arranged symmetrically along the central axis of antenna frame and ground plane. By inserting an isolation aid between two PIFAs the isolation is improved maximum 5dB and 7dB for 2.4GHz band and 5GHz band respectively. Total efficiency is above 60%. ECC is below 0.1.

• ETRI Journal
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• v.35 no.1
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• pp.51-57
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• 2013

In this paper, a small internal antenna for a mobile handset is presented using multiband, wideband, and high-isolation multiple-input multiple-output techniques. The proposed antenna consists of three planar inverted-F antennas (PIFAs) that operate in the global system for mobile communication (GSM900), the digital communication system (DCS), the personal communication system (PCS), the universal mobile telecommunication system (UMTS), and wireless local area network (WLAN) bands with a physical size of $40mm{\times}10mm{\times}10mm$. A resonator attached to the folded PIFA creates dual resonances, achieving a wide bandwidth of approximately 460 MHz, covering the DCS, PCS, and UMTS bands; a meander shorting line is used to improve impedance matching. Additionally, a modified neutralization link is embedded between diversity antennas to enhance isolation, which results in a 6-dB improvement in the isolation and less than 0.1 in the envelope correlation coefficient evaluated from the far-field radiation patterns. Simulation and measurements demonstrate very similar results for S-parameters and radiation patterns. Peak gains show 3.73 dBi, 3.77 dBi, 3.28 dBi, 2.15 dBi, and 5.86 dBi, and antenna efficiencies show 56.15%, 72.15%, 68.59%, 52.92%, and 82.93% for GSM900, DCS, PCS, UMTS, and WLAN bands, respectively.

• Journal of IKEEE
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• v.17 no.3
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• pp.385-392
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• 2013

In this paper, microstrip antenna to enhance the isolation between transmitting port and receiving port under the proximity objects is proposed, and applied to the Doppler radar sensor working at 5.8GHz ISM band which detects vital signals of a human body. Two 3dB quadrature hybrids are placed around radiation patch to form a balanced structure between transmitting port and receiving port, such that it consistently provides enhanced Tx/Rx isolation and excellent return loss over nearby objects. It is theoretically analyzed and simulated to verify the validity of the proposed application. The fabricated antenna that is 2mm away from the human body, has more than 16 dB return loss and at least 30dB isolation over ISM frequency band of 5.8GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1213-1221
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• 2005

In this paper, dual-polarized antenna for UHF RFID reader has been described. Feeding network and antenna structure have been designed, such that both port isolation between transmitting and receiving port and cross-polarization be maximized, and overall antenna size be minimized as well. In addition, sequentially rotated feeding scheme has been adopted to secure axial ratio bandwidth in the circular polarization. Test results show 2.35 dBi antenna gain in 900 to 928 MHz frequency range and 150 MHz axial ratio bandwidth, respectively. And, the proposed antenna has a port isolation of -40 to -38 dB and a cross-polarization of -40 to -30 dB.