• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1264-1271
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• 2009

In this paper, the chip slot antenna which is used for mobile devices and designed for multi-band is proposed. The proposed antenna is comprised of a chip antenna(10 mm$\times$20 mm$\times$1.27 mm) and a system circuit board(30 mm$\times$60 mm$\times$0.8 mm). The chip slot antenna is mounted on the system circuit board and the end of F-type strip line which is patterned on the chip antenna is connected by a via with a ground plane of the system circuit board. So, a chip antenna radiates effectively the energy by transition between a microstrip line of the system circuit board and a open slot structure of the chip antenna. In the results of proposed antenna, impedance bandwidth of 3:1 VSWR(-6 dB return loss) is 1.98 GHz(1.61~3.59 GHz) and 0.8 GHz(5.2~6 GHz). So, it can cover multi-band of DCS, PCS, UMTS, WLAN. The proposed antenna can be applied to mobile devices.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.562-571
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• 2008

In this paper, we propose a novel structure of a spiral antenna with a CP characteristic for RFID reader in UHF band. Since the proposed antenna can be built by printing on a FR-4 substrate, it is appropriate for low-cost mass-production. The antenna is designed to operate in UHF band of $860{\sim}960$ MHz. The CP bandwidth is Increased enough to cover an overall UHF RFID band by using a spiral structure for the antenna arm. The matching bandwidth is broadened by using a quarter-wave transformer between the fred and the antenna body. The proposed antenna has advantages of its easy gain and pattern control with a small antenna size. The measured antenna performance shows the matching bandwidth of 13%, the CP bandwidth of 23%, and the gain of 6.5 dBi. This verifies that the proposed antenna is appropriate for RFID antennas in UHF band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.239-246
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• 2013

In this paper, a dual-band on-body antenna operating at MICS and ISM band for a wireless medical repeater system is proposed and the antenna performance including the human body effect is investigated. The designed dual-band antenna is comprised of a top patch for ISM band and bottom patch for MICS band. Simulation and measurement was carried out in order to analyze the effects of human body on antenna performance considering real use. The proposed antenna has required impedance bandwidth enough to cover both MICS and ISM bands. The measured peak gains were -12.47 dBi and 1.71 dBi at the each center frequency of MICS and ISM bands, respectively. Furthermore, the antenna has the maximum radiation directed toward the inside of the human body in the MICS band and directed toward the outside in the ISM band. In addition, the return loss property of the antenna is insensitive to human body effects so that the proposed antenna is well suited for the on-body wireless medical repeater system.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.3
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• pp.10-14
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• 2017

A reverberation chamber is widely used in mobile handset measurements due to its faster and simpler measurement process compared to traditional anechoic chambers. We propose an ultra-wideband inverse conical antenna design suitable as a reference antenna in a reverberation chamber. Traditionally, multiple discone antennas are needed to cover more than 10:1 operation bandwidth of a reverberation chamber. The proposed inverse conical antenna offers wideband impedance matching bandwidth by virtue of the linear impedance transition along its oblique side. The antenna is feasible to mount on the conductive walls which can be utilized as a ground to improve the matching bandwidth, antenna gain and radiation patterns. The antenna geometry is optimized using a 3D electromagnetic simulation tool and fabricated using a 3D printer. The measured results show that the antenna reflection coefficient lower than -10dB and radiation efficiency more than 70% at the frequency range of 0.65~7 GHz.

• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.4
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• pp.28-34
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• 1975

텔레비젼 수신용 안테나로써 가장 널리 사용되고있는 Yagi안테나는 구조가 간단하고 지향성 이득등이 좋으나 방사주파수에 대한 반파장길이의 소자를 사용하므로 칫수가 커지고 주파수대역이 좁다. 따라서 설치 취급등에 불편을 느낄 경우가 많다. 한편 최근 일반적으로 아무곳에서나 용이하계 설치할 수 있을만큼 소형이면서 화질이 좋은 수상이 가능한 수신안테나에 대한 요망이 커지고 있는데 본 연구에서는 그 파장에 비해서 소형인 폴디드·다이폴 안테나 소자 2개를 좁은 간격으로 배열하고 이들을 이상결합하므로써 VHF텔레비젼전파의 고채널 주파수대에서 비교적 양한 단일지향성을 얻고 있다. 본 안테나에 능동소자를 이용한 저잡음광대역증폭기를 삽입한다면 다소자 Yagi안테나에 비나될 전후방비를 갖는위에 그의 이득도 크게 증가되어 일반수상안테나로 뿐만 아니라 고우스트 방지용실내안테나로서 상당한 기여틀 할것으로 생각된다. The Yagi antenna, which is most widely used for television receiving, has simple form and good directiyity as well as high gain, but it must be made with linear elements of half wave length. Therefore, the dimension of multi-element Yagi antenna becomes bulky and so a(ten it is inconvenient to install and handle, because of its big size. Moreover the frequency band width of the Yagi antenna is usually not broad enough to cover the total frequency range of VHF TV channels in our country. Recently, the aemand for an antenna which is not only small enough to install it easily anywhere but also assures good quality of pictures is generally increasing. In this study 2 elements o( folded dipole, which is small compared to its electrical ways length, are fixed parallel to each other with a narrow distance and the emfs induced in them are made to get together with some phase difference. This new phased array antenna has shown a relatively good unidirectivity through over the high channel VHF television frequency hand as well as the good PIB ratio which is comparable to that of multielements Yagi antenna. As a result this new antenna will be used as a VHF high channel TV receiving antenna and it may become better antighost antenna when used inside the room than other room antennas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1659-1665
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• 2019

In this paper, a novel design of a compact printed monopole antenna for wireless local area network (WLAN) applications is investigated. The radiator with a patch of different line width and step-shaped ground planes is used to reduce the antenna size. The size of the antenna is 16 × 17 × 1 ㎣ and is fabricated with a photolithography technique. The simulated and measured results agree well. The resonant frequency of the investigated antenna is about 5.2 GHz and can cover an impedance bandwidth of 1 GHz for the measurement result. In addition, we presented the measured radiation pattern, presented the gain and efficiency measured in the required WLAN 5 GHz frequency band (5.15-5.825 GHz), and confirmed that it can be used as a 5 GHz band WLAN antenna. The investigated antenna has a small size, light weight, low cost, omni-directional radiation pattern, high gain, and high efficiency.

• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.353-358
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• 2017

In order to reduce the size of the previous stepped slot antenna for UWB applications(3.1 ~ 10.6 GHz) to half, an open ended stepped slot antenna is proposed. The proposed antenna consists of a stepped slot etched on the ground plane as radiation part and a microstrip feed-line with rectangular patch on the top plane for wideband impedance matching. The proposed antenna is designed and fabricated on the FR4 substrate with dielectric constant of 4.3, thickness of 1.6 mm and size of $28.5{\times}32mm^2$. The measured impedance bandwidth (${\mid}S_{11}{\mid}{\leq}-10dB$) of the fabricated antenna is 7.99 GHz(3.01~11 GHz) which is sufficient to cover UWB band (3.1 ~ 10.6 GHz). In particular, it has been observed that antenna has a good omnidirectional radiation patterns and high gain over the entire frequency band of interest even though the size of the proposed antenna is reduced to half when compared with the previous antenna.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.7
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• pp.567-575
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• 2014

This paper suggests an installation procedure of a smart skin prototype into an aircraft, flight demonstration test procedures and test results. Four communication and navigation antennas are embedded into one Conformal Load-bearing Antenna Structure(CLAS). Log periodic patch type antenna was designed as a multi-band antenna to cover four antenna frequency bands. The requirements of CLAS were verified by ground tests before aircraft installation. A CLAS speed-brake was installed into KT-1 aircraft and performances of dual antennas were verified as multi-antenna tests on the ground. Electromagnetic compatibility tests were conducted to check compatibility between the CLAS and all existing equipments. Flight demonstration tests were conducted by one sortie of flight test for one antenna. The activeness and continuity of communication and navigation signal during the flight, null area of antenna signal along the circling flight were monitored. The embedded antennas worked better than expected during four sorties of flight tests.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.1037-1044
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• 2008

Radiation efficiency and antenna gain, in this paper, can be increased by the slot on EMI shield painted on the mobile phone back cover. When the EMI slot which has proper dimension and location is located on the EMI paining area in the phone, the increment of antenna current density due to mutual coupling between the antenna and slot derives increment of antenna efficiency. For the verification of EMI slot effect, we apply the EMI slot to the mobile phone which is operating on GSM/DCS/USPCS/WCDMA quad band, and measure $S_{11}$ and antenna efficiency. It's shown that resonant frequency is not changed and radiation efficiencies to frequency channels by EMI slot are increased from 0.21 % to 8.96 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1438-1446
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• 2010

In this paper, we compared and analyzed the antenna characteristics such as bandwidth, efficiency, and readable range in terms of the size and the number of turns of the multiple meander RFID tag antenna in the UHF band. The sizes of the each antenna are $20.0{\times}19.7$, $25.0{\times}24.8$ and $30.0{\times}29.7\;mm^2$. The bandwidths of the antennas for VSWR<5.8 are 857~963 MHz, 844~965 MHz, and 844~968 MHz which cover the worldwide UHF RFID bandwidth. The readable range of the antenna was greatly affected by the efficiency and gain of the antenna which depends on the size and the number of turns of the meander antenna.