• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.28-31
• /
• 2004

This paper describe analysis active microstrip antenna with low noise amplifier at 900 MHz for mobile communication. The microstrip patch antenna is integrated with low noise amplifier on a permittivity 4.5 (Epoxy-FR4) and thickness of substrate 1.6 mm. Low noise amplifier is designed by using GaAs FETs. The analysis characteristics of antenna include return loss, input impedance, vswr, radiation pattarn, bandwidth and gain of antenna. Mesurement gain of antenna is shown 19.2435 dBi.

• ETRI Journal
• /
• v.35 no.1
• /
• pp.51-57
• /
• 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 the Korea institute for structural maintenance and inspection
• /
• v.7 no.2
• /
• pp.177-184
• /
• 2003

A series of experimental work has been conducted to evaluate the capability of Ground Penetrating Radar (GPR) system in detecting delamination inside concrete. Three antenna at 900 MHz, 1000 MHz, and 1500 MHz frequency are used in the experiments for laboratory size specimens, and 400 MHz antenna has been used for a large size specimen. The laboratory size specimens have the dimensions of 1,000 mm (length) ${\times}$ 600 mm (width) ${\times}$ 140 mm (thickness) with a delamination of 200 mm (length) ${\times}$ 600 mm (width) ${\times}$ 140 mm (thickness). The cover depth of the delamination is varied as follows: 20 mm, 30 mm, 60 mm, and 70 mm. In all cases, the delamination has been successfully identified. The property of three frequencies was seized about detecting delamination. Also, it was shown that the image results in GPR were improved by signal processing.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.61 no.1
• /
• pp.1-4
• /
• 2012

In this paper, the planar type modified folded loop antennas for S-DMB band is proposed. The proposed antenna consisted of opened center of a conventional closed loop and folded terminal of microstrip line to inside loop antenna. The sizes proposed antenna was minimized by folding the terminal of the loop. Also, It was minimized reactance value by increasing capacitances between coupled microstrip line. Therefore the proposed antennas compacted about 20% than a conventional loop antenna and increased efficiency of antenna. The proposed antennas got an omni-directional pattern, the antenna gain was 3.67 [dBi] and the bandwidth was 900 MHz (2.6-3.56 GHz) with VSWR${\leq}$2 from the simulated and the measured results. The frequency utilization coefficient was 29.9 %. These properties could satisfy the S-DMB band.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.13 no.1
• /
• pp.61-66
• /
• 2014

This paper describes the design, fabrication, and measurement of a compact hexa-band coupling antenna for 4G mobile handset using a small element with two slots. In order to obtain sufficient bandwidth (LTE700, GSM850, GSM900, GSM1800, GSM1900, UMTS) with a Voltage Standing Wave Ratio $(VSWR){\leq}3:1$, two slots are inserted in the small element, and coupling patch is used. The measured result of the fabricated antenna provides 410MHz bandwidth form 0.688 to 1.098GHz and 643 MHz bandwidth form 1.607 to 2.250GHz (${\leq}VSWR 3:1$) with the gain ranging from -0.52 to 4.68 dBi. Also, a good radiation pattern is achieved within the hexa-band (0.698-0.960GHz and 1.710-2.170GHz) range.

• Journal of Korea Society of Industrial Information Systems
• /
• v.14 no.1
• /
• pp.9-16
• /
• 2009

In this paper, a method is proposed for the analysis of radiowave receiving characteristics of an ammunition with electric detonator. In this method, an ammunition with electric detonator is modelled as a receiving antenna with its gain obtained by computer simulation or measurement. The induced radiowave power is obtained by inserting the gain of the electric detonator in the antenna coupling formula. Radiowave receiving characteristics at very close distances are obtained by Treasuring the transmission coefficient between a half-wave dipole and the electric detonator model. Radiowave receiving characteristics of the electric detonator in a 105mm tank ammunition are obtained using the proposed method and the safety of the 900 MHz RFID reader on the detonator is assessed.

• Journal of information and communication convergence engineering
• /
• v.8 no.5
• /
• pp.489-492
• /
• 2010

This paper proposes the planar-type modified monopole antennas of loop structure. This antenna has an opened center of a conventional closed loop structure with an inside-folded terminal of the loop microstrip line. The size of the proposed antenna was minimized by folding the end of the loop. Also, the reactance value has been minimized by increasing capacitances between the coupled microstrip line. Therefore the proposed antenna has been compacted to about 20% from a conventional loop antenna and has increased its efficiency. The proposed antennas have an omni-directional pattern, the antenna gain was 3.67 [dBi] and the bandwidth was 900 MHz (2.6~3.56 GHz) with VSWR$\leq$2 from the simulated and the measured results. The frequency utilization coefficient was 29.9%. These properties could satisfy the S-DMB band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.4
• /
• pp.404-410
• /
• 2008

In this paper, circular polarized microstrip antenna with a conducted hollow cylinder-typed via around the coaxial probe is proposed to enhance the bandwidth of an RFID portable reader microstrip antenna. An antenna of thickness of 6.4 mm and size of $84{\times}84\;mm$ is manufactured with FR4 substrate and its 10 dB return loss bandwidth is measured to be 92 MHz, which is about three times large than the same size's microstrip antenna without hollow cylindrical via. The measured antenna gain and the axial ratio at each are $0.01{\sim}1.825\;dB$ and $2.3{\sim}8.2\;dB$ within 10 dB return loss bandwidth, respectively.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2001.11a
• /
• pp.96-100
• /
• 2001

본 논문에서는 skeleton slot 복사기를 이용하여 GSM 900과 GSM 1800에서 사용할 수 있는 이중대역 안테나를 설계 및 제작하여 측정 결과를 비교 분서하였다. 기본적인 skeleton slot 구조에서는 낮은 밴드의 2배 이상의 주파수에서는 수평 빔폭이 일정치 않고, 정재파비 특성이 불량하였으나, 급전부와 측면 방사부분의 다중경로 형성 및 절곡 구조를 이용하여 이를 해결하였다. 안테나의 크기는 반사판이 190$\times$190(mm), 복사기는 154$\times$106(mm), 높이는 33mm로 하여 현재 서비스 사업자틀이 주로 사용하는 크기로 구성하였다. 구성 재질은 1mm 두께의 알류미늄판을 이용하며, 이를 NCT로 타공 및 절곡하여 제작하였기 때문에 대량 생산 시 단가를 낮출수 있다. 실측결과 900MHz 대역에서 13.7%, 1800MHz 대역에서 16.4%의 -l0dB 반사손실 대역폭을 만족하고, 방사패턴도 대역별로 $\pm$1$^{\circ}$이내의 일정한 양상을 보여 이중대역 안테나로서의 요구를 만족하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.2
• /
• pp.181-188
• /
• 2012

In this paper, the measurement data is analyzed and channel parameters are derived through MIMO Channel measurements at 781MHz considering outdoor multi-path environment. 781MHz frequency band currently operates the DTV system. However, it will be allocated new mobile communication frequency band. The channel characteristics at 781MHz seem to be similar existing mobile communication system at 900MHz but a study on channel characteristics of signal transfer process is necessary because there is incomplete study in mobile networks at 781MHz. To avoid interference with Korean DTV broadcasting, we measured channel characteristics in city/suburban areas of Jeju island by channel sounder and $4{\times}4$ antenna of the ETRI(Korea Electronics and Telecommunications Research Institute). Path Loss, Delay Spread, Angular Spread and K-factor were derived based on measured data.