• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.227-228
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• 2008

A diagnosis based on EM is composed of multi-channel transceiver, antennas in illumination tank, liquid and image reconstruction algorithm for solving inverse scattering problem. The antennas in diagnosis were fabricated and measured in lossy liquid. The 10dB impedance bandwidth of the antenna is 600MHz - 3.5GHz

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1661-1666
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• 2014

In this paper, a compact planar ultra wideband (UWB, 3.1~10.6GHz) multiple-input multiple-output (MIMO) antenna is proposed. This antenna consists of two monopole planar UWB antennas and T-shaped stub decoupling between two antennas. The T-shaped stub improve the isolation characteristic at the wide band. The evolution strategy(ES) algorithm is employed to optimized design. As a result, optimized antenna has a return loss less than -10dB and the isolation less than -15dB from 3.1GHz to 10.6GHz. During the optimization process, the antenna gain is enhanced at lower band and the envelope correlation coefficient(ECC) is lower than 0.003.

• International journal of advanced smart convergence
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• v.13 no.2
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• pp.1-6
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• 2024

Reconfiguration and miniaturization of antennas have become key attributes in modern wireless communication systems. Reconfiguration of radiation pattern can alleviate the problems encountered in modern wireless communication systems such as multi-path problems. Physical limitation of miniaturization also can be overcome by using a zeroth-order resonance (ZOR) antenna based on metamaterial. In order to achieve reconfiguration and miniaturization of antennas at the same time, we propose a new pattern reconfigurable zeroth-order resonance (ZOR) antenna that reconfigures the radiation patterns by varying the position and the number of unit cells comprising the antenna. The antenna is fabricated in an equilateral triangular shaped symmetrical structure to increase pattern variety. This structure can easily provide eight different radiation patterns (two omnidirectional and six monopole like patterns).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.149-152
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• 2000

본 논문에서는 전자계의 시간 변화 파형을 측정하기 위한 모노폴 안테나의 감도 특성을 개선하기 위해 리액턴스 소자를 안테나에 직렬 또는 병렬 연결한 경우의 감도 특성에 관하여 검토하고 있다. 이론 해석의 결과, 리액턴스 소자를 병렬로 연결할 경우에는 장하 리액턴스의 갑이 무한대일 때 감도 특성이 가장 양호하였으며, 직렬로 연결한 경우에는 최대의 감도 특성을 갖는 리액턴스의 값이 존재한다는 것을 알 수 있었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.6 s.97
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• pp.563-570
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• 2005

In this paper, a small-sized planar square-spiral monopole antenna is proposed by using parasitic elements. The Parasitic element is composed of a crossed strip and additional right-angle folded(L-type) stirps. And these parasitic elements are printed on a substrate which is the opposite side of a radiation element . When the parasitic elements are used, the size of the square-spiral monopole antenna is reduced by $32\%$ for the same operating frequency compared to the antenna without parasitic elements. The radiation pattern of the proposed antenna is nearly omni-directional in azimuth. The designed antenna can be used in the application of channel 12 digital mulimedia broadcasting(DMB) handset.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.631-638
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• 2009

In this paper, a wide-band monopole antenna for use in PCS/WDCMA/Wivro/S-DMB(1.750${\sim}$2.655 GHz) band is presented. The presented antenna is a trapezoidal monopole antenna which has back-side patch and improves the bandwidth. To confirm the wide-band characteristics and radiation pattern of presented antenna, the experimental antenna is fabricated and its radiation characteristics are measured, compared with calculated results. It is shown that the designed antenna has VSWR less than 1.5, gain over 2 dBi in 1.73${\sim}$3.48 GHz. The measured results show good agreement with calculated results. From the result, we confirm that the designed antenna can be used indoor antenna for PCS/WCDMA/WiBro/S-DMB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.558-566
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• 2003

We fabricated thick film monopole antennas using Li-doped BiNbO$_4$ ceramics and investigated their electrical properties as a function of the Li-doping concentration. Compared with undoped BiNbO$_4$ ceramics, addition of Li$_2$CO$_3$ improved dielectric constant by increasing of ionic polarization, but reduced quality value by increasing of lattice distortion. Antenna properties like gain, bandwidth and radiation patterns were also greatly affected by the addition of Li$_2$CO$_3$. With increasing amount of Li$_2$CO$_3$, the bandwidth of ceramic monopole antenna was increased to 81.7 %, but the gain was reduced to -10.03 dBi. Also radiation patterns were so distorted and showed low dB value by increasing of dielectric loss.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4537-4542
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• 2010

In this paper, the antenna radiation pattern inside the vehicle is presented for observing the change occurring in non-anechoic environment using monopole antenna. The environment for radio communication can be affected by antenna characteristic variation inside the small space existing multi reflection waves. To perform simulation and measurement about antenna radiation pattern, the radio frequency bands for GPS and Wibro services expected to use inside the vehicle is selected. The simulation is based on the ray-tracing method and the radiation pattern is measured inside the vehicle and in free space using monopole antenna having those frequency bands. In accordance with the measurement and simulation results, when two antennas are put inside the vehicle, the omni-directional characteristic of the antenna is maintained but the received power is increased than free space case and the difference between the each case of measurements is increased as the operating frequency is increased.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1098-1106
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• 2007

This paper presents active antenna diplexers implemented into an ultra-wideband CPW(Coplanar Waveguide) fed monopole antennas. The proposed active antenna diplexer is designed to direct interconnect the output port of a wideband antenna to the input port of two active(HEMT) devices, where the impedance matching conditions of the proposed active integrated antenna are optimized by adjusting CPW(Coplanar Waveguide) feed line to be the length of 1/20 $\lambda_0$(@5.8 GHz) in planar type wideband antenna. The measured bandwidth of the active integrated antenna shows the range from 2.0 GHz to 3.1 GHz and from 5.25 GHz to 5.9 GHz. The measured peak gains are 17.0 dB at 2.4 GHz and 15.0 dB at 5.5 GHz.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.67-74
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• 2014

In this paper, we designed a multiband monopole antenna for next-generation WLAN system. In conventional WLAN system, UWB antennas were used together, and, because the radiation occurs in different parts depending on the antenna structure, it has the disadvantage of having an unstable impulse response characteristic due to dispersion characteristics. Although a UWB antenna that has suitable radiation pattern for WLAN band, it does not have good impedance matching and has severe echo. Therefore, in this paper, a monopole antenna was designed by using CPW power feed so that various impedances can be easily implemented when designing an antenna and more parameters can be derived that can be used for design for optimal performance.