• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2325-2331
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• 2012

Planar square-spiral antenna using a strip conductor is proposed and analyzed for RFID system in UHF band operating from 860MHz to 960MHz. By varying the length of common line, detached distance, strip line-space, strip line-width and the number of spiral turn, the optimized antenna are designed and fabricated in compact size without a matching-stub between the input port of the proposed antenna and RFID tag chip. From the optimized results, the frequency bandwidth in VSWR<2 has covered 100MHz in the RFID UHF band. The antenna gain has obtained 3.5dBi at the center frequency of 910MHz and the desired beam pattern has shown directional pattern on elevation and azimuth angle. Therefore, the proposed antenna is suitable for practical RFID applications requiring various tag chips with the specific input impedance.

• Journal of IKEEE
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• v.20 no.1
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• pp.68-74
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• 2016

In this paper, we present a compact planar dual band rejection Ultra Wide Band(UWB) antenna with folded parasitic element. The proposed antenna is consist of a hexagonal planar radiation patch antenna with a folded parasitic element which is located over the top and bottom surface. In contrast with other antenna which rejects single band using one method, folded parasitic element rejects dual band using one simple structure. Owing to folded parasitic element, dual-rejected properties are achieved in the Worldwide Interoperability for Microwave Access(WiMAX), C-band, and Wireless Local Area Network(WLAN) bands. The bandwidth of the proposed antenna was measured as 3.1~10.6 GHz for voltage standing wave ratio(VSWR) less than 2, except for the dual rejection bands of 3.4~4.2 GHz and 5.15~6.00 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.275-281
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• 2011

In this paper, we proposed the small planar monopole antenna with modified ground plane for UWB communications. The proposed antenna not only shows Ultra-Wideband characteristic(3.1~10.6 GHz) suitable for UWB communications but has partially notched-band characteristic to reject 5 GHz WLAN band(5.15~5.35 GHz, 5.470~5.825 GHz). The proposed antenna improved impedance matching through two slits on ground plane, and the rejection band was induced by two ${\lambda}$/4 open stubs on center of two slits. Fabricated antenna satisfied VSWR${\leq}$2 in 2.88~10.83 GHz except for the band rejection of 5.08~5.83 GHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.564-566
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• 2012

In this paper, a design method for a compact broadband planar monopole antenna fed by coplanar waveguide (CPW) is studied. The proposed broadband monopole is optimized for terrestrial digital television (DTV) receiving. The monopole is fed by a CPW with 75-ohm characteristic impedance on an FR4 substrate and its size is $100mm{\times}200mm$. A pair of slit is appended for size reduction and an inductive stub is loaded for the impedance matching between the feedline and monopole. The optimized monopole antenna for DTV band (470-806 MHz) is fabricated on an FR4 substrate and tested experimentally to verify the results of this study.

• Journal of electromagnetic engineering and science
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• v.1 no.1
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• pp.67-72
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• 2001

In this paper, the plano-convex lens antenna fed by a single patch is studied for a microwave remote-traffic monitoring sensor with constraints of small size and low cost. Measurement of an AUT (Antenna Under Test) involves the considerations of a triangular groove for matched layer and metallic shielding effects. A formulation for extracting the parameters of a piano-convex lens antenna, based on geometrical optics, is introduced using Fermat`s principle of the equi-phased ray condition. Teflon ($\varepsilon_{{\gamma}}$/ =2.0) is chosen as a material of a plano-convex lens antenna for adjustment of aberrations on the lens surfaces automatically. A fabricated plano-convex lens shows 3-dB beamwidth of 7.5 degree and side-lobe level of -29 dB with an aperture distribution of the parabolic-squared taper on pedestal. This lens supports easier integration with the planar microwave circuits by using a microstrip single patch as a primary feeder of the lens antenna.feeder of the lens antenna.

• Journal of IKEEE
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• v.24 no.1
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• pp.90-96
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• 2020

As various communication services have emerged due to the development of mobile communication technology, there is a need for a wideband antenna supporting multiple communication services with one antenna. In this paper, we propose a planar slot wideband antenna that can support all the communication services of 3.1~4.99GHz, the low frequency band of 5G, in addition to the existing communication services such as WiFi, LTE 2300/2500, and WiMAX. Through the simulation, the optimized antenna design parameters were obtained, and the antenna was fabricated to implement an antenna with a frequency bandwidth of 1.96~6.01GHz (S11 <-10dB) and presented the radiation pattern and gain of the antenna. The proposed antenna is a multi-band antenna that can provide all the services of LTE, Wifi, WiMAX, and 5G low frequency bands. It can be used as a repeater antenna in radio shadow area such as buildings, dense areas, and ships.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.492-499
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• 2016

Null pattern synthesis method using the Quantum-inspired Evolutionary Algorithm(QEA) is described in this study. A $12{\times}12$ planar array antenna is considered and each element of the array antenna is controlled by 6-bit phase shifter. The maximum number of iteration of 500 is used in simulation and the rotation angle for updating Q-bit individuals is determined to make the individual converge to the best solution and is summarized in a look-up table. In this study we showed that QEA can satisfactorily synthesize the null pattern using smaller number of individuals compared with the conventional Genetic Algorithm.

• Journal of electromagnetic engineering and science
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• v.13 no.2
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• pp.63-72
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• 2013

The ultra-wideband (UWB) spectrum available for commercial applications has offered us an opportunity to achieve high-speed wireless communications and high-accuracy location applications. As one of key research areas in UWB technology, a lot of innovative broadband and miniaturization techniques for UWB antennas have been greatly invented and developed for years. This paper reviews the development of UWB antenna design in the past decade. Starting with a brief introduction of the specific requirements and promising applications of UWB systems, the unique design challenges of UWB antennas are highlighted. Next, the important milestones of UWB antenna designs are briefed. After that, a variety of planar UWB antennas invented for broadband operation, miniaturization, and multiple functions are introduced. Last, the comments on the development of UWB antennas in future are shared.

• Journal of Electrical Engineering and Technology
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• v.7 no.1
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• pp.86-90
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• 2012

A two-dimensional nonlocal heating theory of planar-type inductively coupled plasma source has been previously reported with a filamentary antenna current model. However, such model yields an infinite value of electric field at the antenna position, resulting in the infinite self-inductance of the antenna. To overcome this problem, a surface current model of antenna should be adopted in the calculation of the electromagnetic fields. In the present study, the reactor impedance is calculated based on the surface current model and the dependence on various discharge parameters is studied. In addition, a simpler method is suggested and compared with the surface current calculation.

• Journal of Industrial Technology
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• v.31 no.A
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• pp.109-112
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• 2011

In this paper, we proposed a planar reversed triangle monopole antenna for UWB(Ultra Wideband) communication. RF-60A substrate of 0.64 mm thickness and 6.15 relative permitivity and 0.035 mm conductor of thickness and loss tangent 0.0025 is used for implementation. We have used Ansoft $HFSS^{TM}$(High Frequency Structure Simulator) to simulate the proposed antenna. The proposed antenna showed return losses about -10 dB, nearly omni-directional radiation patterns and maximum gains are over -5 dBi at the frequency band from 3.1 GHz to 10.6 GHz for ultra wide band communication.