• 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 electromagnetic engineering and science
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• v.17 no.1
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• pp.14-19
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• 2017

In this paper, a planar directional beam-switchable antenna with four orthogonal beam directions is proposed. The proposed antenna is designed with two crossed active elements and two parasitic elements for each direction. The design methodology is described on the basis of the Yagi-Uda method for the active and parasitic elements, respectively. By adjusting the effective electric lengths of the parasitic elements, the roles of a director and a reflector are exchanged with each other. The planar four-way beam-switchable Yagi-Uda antenna is implemented. From the experimental results. The proposed design method is verified for orthogonal radiation beam switching.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.55-59
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• 2021

Generating electromagnetic waves with Orbital Angular Momentum (OAM) properties is a fast-growing research subject in both radio and optics. This paper describes the generation of OAM carrying waves using a circular array of rectangular planar monopole antennas. The proposed design combines simplicity, compactness, and most importantly very wideband of operating frequencies (about 20-160 GHz, bandwidth ratio about 1:8) which makes it suitable for future applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.11
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• pp.1121-1127
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• 2014

In this paper, a planar frequency reconfigurable antenna is proposed with variable capacitors. The proposed one is designed with a planar monopole, and varies resonant frequencies by variable capacitive loading of a varactor diode. The equivalent circuit and electromagnetic(EM) simulation are utilized for the analysis at the variable characteristic design of the antenna, and the same radiation performance. The implemented frequency variable monopole antenna has been verified by comparing prototypes with designed capacitors and ones with biased varactor diodes. The proposed antenna has presented the resonant frequency variations from 2.25 GHz to 2.42 GHz.

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

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.12
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• pp.9-15
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• 1996

An electric field induced by a point dipole soruce within a conductor-backed lossy dielectric slab above the earth is calculated by anumerical method. the calcualtion is peformed on the plane which is parallel to the conductor plane and containing the point dipole soruce. Computed S$_{21}$ values of two parallel planar dipole antennas and two collinear planar dipole antennas are compared against each other, as well as the electic field magnitudes in those arrangements.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.45-46
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• 2014

In this paper, measurement methods for the characteristics of antennas for indoor digital TV (DTV), having 75-ohm port impedance, are introduced. Reference impedance of typical radio frequency (or microwave) systems and measurement equipments is 50 ohm. However, the reference impedance of antennas for indoor DTV is 75 ohm, and the characteristics of the antennas cannot be measured directly using the measurement equipments. Measurement methods, using test equipments with reference impedance of 50 ohm, for the characteristics(impedance, radiation patterns, and gains) of antennas designed to fit for 75 ohm port are introduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3431-3436
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• 2013

Band-notched ultra-wideband (UWB) antennas using frequency selective surfaces (FSSs) are presented. The proposed antennas utilized the band rejection characteristic of typical FSS unit cells. We loaded the FSS unit cells on the same plane of planar UWB antenna. These antennas are designed to reject the interference from the wireless local area network band, 5.15-5.825 GHz in the UWB band, 3.1-10.6 GHz. The measured peak gains of the proposed antennas are more than 2 dBi at both operation edge and center frequencies, and sufficient to apply for commercial purpose. The antennas are small size and planar shape for the purpose of the small mobile application, and enhanced design freedom by using various existing FSS unit cells.

• Journal of information and communication convergence engineering
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• v.8 no.5
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• pp.489-492
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• 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 Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.1
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• pp.70-74
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• 2015

In this paper, we have illuminated the radiation modes of rectangular planar antennas to interpret the nature of the wideband characteristic upon which formulas for bandwidth prediction are presented. Rectangular planar antennas are being investigated by many researchers in virtue of relatively simple design and fabrication procedures to replace the cylindrical monopoles. But the design principle for rectangular planar antennas is still based on that of cylindrical monopoles, and the nature of the wideband characteristic and the formula to estimate the upper band frequency are not analyzed yet. In this research, we have shown the patterns of the radiation modes explaining the wideband characteristic and also proposed the upper band frequency with minor modification for the lower band frequency formula based on mode formation principles. Finally we have confirmed the validity of our results, within 10 % accuracy, by the application to some published results.