• 전기학회논문지P
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• 제64권3호
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• pp.121-124
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• 2015

In this paper, we developed the compact Doppler radar using the compact dual-circularly polarized antenna for medical application. The operating frequency is 2.47 GHz for considering ISM band. In order to decrease the size of the entire system, we designed the compact antenna and located the circuit board at the back of the antenna. The simulation of the proposed antenna was performed by the finite difference time domain (FDTD) method. The total volume of the proposed system is $65{\times}45{\times}6mm^3$ including the antenna. From the experiment, the developed bio-radar could be used to support the device for medical applications.

• ETRI Journal
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• 제34권5호
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• pp.767-770
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• 2012

This letter presents a novel compact circularly polarized patch antenna for Global Positioning System/Global Navigation Satellite System (GPS/GLONASS) applications. The proposed antenna is composed of a simple square radiating patch fed by a capacitive dual-feeder to increase the impedance bandwidth and a lumped element hybrid coupler to achieve the broadband characteristic of the axial ratio (AR). The realized antenna dimensions are $28mm{\times}28mm{\times}4mm$, which is the most compact size among the dual-band GPS/GLONASS antennas reported to date. The measured results demonstrate that the proposed antenna has a gain of 2.5 dBi to 4.2 dBi and an AR of 0.41 dB to 1.51 dB over the GPS/GLONASS L1 band (1.575 GHz to 1.61 GHz).

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.473-477
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• 2003

In this paper, a integrated structure of a two-element microstrip patch antenna with two feeds for GPS/PCS dual-band operation is proposed. The radiating element for PCS operation is a novel broad band low-profile cylindrical monopole top-loaded with a shorted meander patch, which gives linearly polarized conical radiation pattern and size reduction of patch due to meander line. The radiating element for GPS operation is a novel square-ring microstrip patch with truncated corners and slits. which provide circularly polarized broadside radiation patterns and size reduction due to slots. using dielectric substrate in GPS antenna of proposed antenna provide to improve isolation between two feeds and reduce size of patch. The proposed antenna achieves the bandwidth and polarization requirements of GPS and PCS systems.

• 한국정보통신학회논문지
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• 제14권7호
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• pp.1537-1543
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• 2010

본 논문에서는 이중편파들을 수신할 수 있는 소형 마이크로 스트립안테나를 제안하였다. 우선원형편파와 좌선 원형편파를 동시에 수신할 수 있어 편파 다이버시티 환경을 제공한다. 패치 내부에 정사각형 모양의 빈 공간을 두어 소형화를 구현하였다. 그리고 패치를 회전시켜 다이아몬드 형태를 만들고 급전선 주위에 슬롯을 두어 임피던스 정합이 용이하게 하였다. 제안된 안테나는 GPS(global positioning system)에 적용되어 설계되었으며 시뮬레이션을 통해 이론의 타당성을 입증하였다. 제작된 안테나를 측정한 결과 우선원형편파 신호를 수신하는 경우에, 정재파비 2:1 특성을 나타내는 83MHz 대역폭, 약 58MHz 의 3dB 축비대역폭, 90도의 3dB 빔폭 과 0dBi의 이득을 나타낸다. 또한 좌선원형편파를 수신하는 경우에도 유사한 특성을 보여준다.

• 전기전자학회논문지
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• 제13권3호
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• pp.72-79
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• 2009

본 논문에서는 이중 원형 편파 특성을 갖는 소형 마이크로스트립 능동 안테나에 대해 기술하였다. 제안된 안테나는 좌수원형편파와 우수원형편파를 선택하여 수신할 수 있는 다이버시티 기능을 갖는다. 방사체용 마이크로 스트립 패치의 내부에 정사각형 빈 공간을 두어 소형화를 시켰으며 급전선로 주변에 슬롯을 위치시켜 임피던스 정합이 용이하게 하였다. 정사각형 빈 공간에는 스위치와 증폭기 회로들이 설계되었으며 이를 통해 편파 모드 선택과 안테나 이득을 증가시켰다. 제안된 안테나는 GPS 에 적용하였으며 임피던스 대역폭을 만족한다. 제작된 안테나는 우수원형편파 동작 시, 3dB 축비 대역폭은 약 50MHz, 3dB 빔 각도는 90도, 13dBi 의 안테나 이득이 측정되었다. 또한 좌수원형편파 동작 시, 3dB 축비 대역폭은 약 50MHz, 3dB 빔 각도는 84도, 약 12dBi 의 안테나 이득이 측정되었다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.427-431
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• 2007

Applications in present-day mobile communication systems particularly require miniaturized dimensions and low-profiles of antenna in order to meet the mobile units. Thus, size reductions and bandwidth enhancements are becoming crucial design considerations for practical applications of microstrip antennas. The motivation of further experiments have been stepped to follow those studies for achieving compact and broadband, even multiplied operation modes, which are greatly increased with much attentions recently. To obtain broadband, single-feed, circularly polarized characteristics of microstrip antennas, a design with feed-line ought to be a factor of two. Usually, diagonally balanced-line feeds with hybrid coupler are employed to attain circular polarizations. We firstly formulated DGS (Defected Ground Structures) based operation principles of the entire microstrip components and therefore were able to derive impedance variance of feed-lines. After verifying corresponding experimental results, we targeted the frequency bands of UHF RFID (Ultra High Frequency Radio Frequency IDentification) and approximately of 0.4-2.4GHz have exhibited remarkable two resonance amplitudes as a dual band antenna. Our secondary researches were aimed to design quad band microstrip antenna which represents four resonance characteristics within the identical frequency bands as well. Microstrip patch has been meandered to lengthen the electrical paths, and the other design criteria with respecting physical parameters including radiation patterns and impedance bandwidths measurements will be described for verification. Advisable applications of these antennas can be GSM850, GSM900, GPS (L1-1575 and L2-1227) and UMTS-2110 of cellular systems, which extremely desire multiband and minimum size.