• 대한전자공학회논문지TC
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• 제46권2호
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• pp.134-140
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• 2009

본 논문에서는 마이크로스트립구조에서 $3.1{\times}10.6GHz$대역의 UWB 통신을 위한 사다리꼴 안테나모델에 대해 광대역화를 검토하였다. 두 사다리꼴의 마이크로스트립패치 치수를 서로 다르게 한 모노폴의 사다리꼴안테나 모델에 대해 컴퓨터 시뮬레이션을 통하여 UWB의 대역폭에서 반사손실 -10dB(VSWR<2)이하의 임피던스 정합특성을 보이는 안테나의 동작특성을 나타내 보였다. 또한, 본 논문에서 구한 최적화 안테나는 UWB의 전 대역에서 선형위상과 수평면내에서 대체로 무지향 방사특성을 나타내 보인다.

• ETRI Journal
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• 제26권6호
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• pp.605-614
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• 2004

In this paper, we investigate array calibration algorithms to derive a further improved version for correcting antenna array errors and RF transceiver errors in CDMA smart antenna systems. The structure of a multi-channel RF transceiver with a digital calibration apparatus and its calibration techniques are presented, where we propose a new RF receiver calibration scheme to minimize interference of the calibration signal on the user signals. The calibration signal is injected into a multi-channel receiver through a calibration signal injector whose array response vector is controlled in order to have a low correlation with the antenna response vector of the receive signals. We suggest a model-based antenna array calibration to remove the antenna array errors including mutual coupling errors or to predict the element patterns from the array manifold measured at a small number of angles. Computer simulations and experiment results are shown to verify the calibration algorithms.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.473-480
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• 2005

A three axes marine satellite antenna has been developed. As a design step, a CAD model for the antenna has been created according to the design requirements. Kinematic analyses are carried out to insure design specification and to check collision detection of the CAD model. Marine satellite antennas experience base motions, and a relevant control system should control the three antenna axis to point to the satellites accurately. A sensor fusion algorithm and a PIDA (Proportional, Integral, Derivative, Acceleration) control algorithm are designed and implemented to control the yaw, level, and cross-level angle of a small size satellite marine antenna. Antenna stabilization control experiments are performed using a test simulator which gives the antenna base motions. Experimental results show small pointing errors, which is less than 0.2 degree for the level, cross-level, and yaw axis.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.338-343
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• 2015

In order to avoid the interference from existing narrowband communication systems, this paper proposes a compact band-notched UWB (ultra wideband) antenna with size of $12mm{\times}22mm{\times}1.6mm$. Transmission line model is applied to analyzing wide impedance matching characteristic of the modified base antenna, which has a gradual stepped impedance feeder structure. The proposed antenna realizes dual band-notched function by combining two biased T-shaped parasitic elements on the rear side with a window aperture on the radiation patch. The simulation current distributions of the antenna reflect resonant suppression validity of the two methods. In addition, the measured radiation characteristics demonstrate the proposed antenna prevents signal interference from WLAN (5.15-5.825GHz) and WiMAX (3.4-3.69GHz) effectively, and the measured patterns show the antenna omnidirectional radiation in working frequencies.

• 제어로봇시스템학회논문지
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• 제21권11호
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• pp.1050-1056
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• 2015

In this paper, we use the characteristics of electromagnetic waves underwater attenuation for estimating linear distance between a transmitting node and receiving node, and research underwater vertical plane attenuation model for constructing the underwater localization system. The underwater localization of 2 dimensional with the plane attenuation model in the horizontal plane (H-plane) was proposed previous research. But for the 3 dimensional underwater localization, the additional vertical plane (E-plane) model should be considered. Because the horizontal plane of omnidirectional antenna has the same attenuation tendency in x-y plane according to the distance, whereas in vertical plane shows an irregular pattern in x-z plane. For that reason, in the vertical plane environment, the attenuation should be changed by the position and inclination. Hence, in this paper the distance and angle between transmitting and receiving node are defined using spherical coordinate system and derive an antenna gain pattern using half power beam width (HPBW). The HPBW is called a term which defines antenna's performance between isotropic and other antennas. This paper derives omnidirectional antenna's maximum gain and attenuation pattern model and define vertical plane's gain pattern model using HPBW. Finally, experimental verifications for the proposed underwater vertical plane's attenuation model was executed.

• 한국통신학회논문지
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• 제22권4호
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• pp.611-617
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• 1997

In this paper a new fading model is proposed, which is well consistent with the real environment of smart antenna applications since it is spatially and temporally correlated simultaneously. The new model(STCFM: Spatially and Temporally Correlated Fading Model) is derived statistically in spatio-temporal domain so that it can provide high accuracy in the evaluation of the smart antenna system. As will be seen, the simulation results agree well with the theory.

• Journal of electromagnetic engineering and science
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• 제2권1호
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• pp.11-15
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• 2002

In this paper, we have proposed the new configuration of wideband antenna using CPW fred lines. The proposed antenna has CPW feed lines and U-slot to achieve wade bandwidth with good impedance matching. The use of CPW feed line can decrease the number of substrates. It is compared with the conventional antenna find by a microstrip fled line. The parameters of CPW fred lines were studied by using the quasi-static approximation which is based on the conformal mapping method. The analysis of CPW discontinuities such as the tapered-step structure and the open ended gap were studied by using the quasi-static approximation which is based on the boundary element method. Also, the equivalent circuit model of multi-layer antenna were proposed using the cavity model. Experiment results of the proposed antenna 7how wide-bandwidth characteristics and good radiation patterns in passband.

• ETRI Journal
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• 제41권4호
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• pp.528-535
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• 2019

The coupling mechanism of a loop-type ground radiation antenna is investigated in this paper. We use the equivalent circuit model of the antenna and a full-wave simulation to explain the coupling mechanism of the antenna. We analyze the effects of various antenna parameters on the coupling between the antenna element and the ground plane to examine the conditions for enhancing the coupling. Based on simulations with the equivalent circuit model, full-wave simulations, and measurements, we propose optimal design considerations for the antenna. The findings of this study will aid the design and understanding of loop-type ground radiation antennas for mobile devices.

• 한국세라믹학회지
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• 제33권9호
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• pp.977-984
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• 1996

This paper analyzes the performance of a rectangular dielectric ceramic antenna by the theoretical cavity model such as input impedance resonant frequency quality factor efficiency and bandwidth. Through a compu-ter simulation variation of the antenna characteristics is found as a function of the antenna parametes. (permit-tivity permeability antenna size etc) Based on the results we propose a new design method for the dielectric ceramic antenna to be employed in Global Positioning Systems.

• ETRI Journal
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• 제28권3호
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• pp.383-385
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• 2006

A new meander-line antenna consisting of two open-ended strips is proposed for a compact and broadband UHF radio frequency identification tag. An equivalent circuit model for the proposed antenna is derived and used to perform a simple and wideband impedance match to an arbitrary complex impedance of a tag chip without any additional matching network. The performance of the proposed antenna is validated by comparing calculated and measured results, which show good agreement.