• Journal of IKEEE
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• v.23 no.3
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• pp.1112-1115
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• 2019

This paper proposes a novel low-profile omni-directional microstrip antenna to mount on the deployable wing of the observation munition. The proposed antenna is designed on seven hexagonal resonators in a quasi-circular array to achieve a monopolar radiation pattern with a thin substrate. By employing the mesh ground structures, the resonant frequencies and impedance bandwidths of the proposed antenna is investigated. To verify the feasibility of the mesh ground structure, the thin ground wire width is investigated theoretically for improving the 3-dB fractional bandwidth, realized antenna gain and quality-factor. The proposed antenna demonstrates a good monopolar radiation in good agreement with the simulation results. The implemented prototype shows the measured bandwidth of 326 MHz with respect to 5.65% centered at 5.77 GHz and realized gain of 5.49 dBi at 5.84 GHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.29-34
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• 2023

A clear and efficient design method for a microstrip-to-waveguide inline transition, which is based on an analytical model, is presented. The transition consists of three parts: a microstrip-to-SIW transition, a dielectric-loaded waveguide with substrate-height, and a stepped-height waveguide. The shape of the transitional structure is formed for impedance matching. Two equivalent type0s of dielectric-loaded transitional structures are proposed. The design method is applicable to any size of the waveguide, but a design method of two Ka-band transitions is demonstrated. The proposed transitions, in a back-to-back configuration, have less than 1.2 dB insertion loss and more than 15 dB return loss from 29.8 GHz to 38.2 GHz.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.358-361
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• 2003

In this paper, a new technique to reduce the phase noise in microwave oscillators is proposed using the resonant characteristics of the Photonic Bandgap(PBG). Microstrip line resonator has the low Q(Qaulity factor). Therefore, as PBG structure was applied, we examined that the phase noise of the oscillator has been reduced.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.416-422
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• 2006

In this paper, we have designed and favricated the high gain and wideband microstrip patch antenna including IEEE 802.11a. To widen the bandwidth of microstrip antenna, firstly we have used the microstrip line-coaxial probe feeding method and inserted a U-slot in the rectangular patch. Secondly, to improve the antenna gain, we have used a $2{\times}2$ array structure. From the measured results, wideband characteristics of 1 GHz bandwidth($5.110{\sim}6.142$ GHz) for VSWR<2 was obtained. The measured eain was 13 dBi in both the E-plane and H-plane at the frequency of 5.15 GHz, 5.35 GHz, 5.50 GHz, and 5.85 GHz.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.121-126
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• 2015

This paper proposes a novel reconfigurable microstrip antenna based on alternating a perturbation structure to achieve circular polarization diversity. The proposed antenna consists of an annular ring microstrip radiator for simultaneously loading stub and slot perturbations which support right- and left-handed circular polarization senses and two PIN diodes for choosing the operating polarization sense. By controlling the states of two PIN diodes between perturbing slot and stub at one diagonal corner of the radiator, reconfigurable circular polarization senses of the proposed antenna are successfully obtained and alternated. The proposed antenna has been theoretically analyzed and experimentally demonstrated at 2.4 GHz of S-band for satellite communication system. The simulation and measurement results of the proposed antenna show in good agreement with the reflection coefficients, axial-ratios, realized antenna gains, and radiation patterns.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.7
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• pp.606-612
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• 2015

This paper proposes a new design of a dual-band orthogonal-polarization microstrip antenna for V2N(Vehicle to Nomadic Device) communication system. The proposed antenna consists of a perpendicular feeding structure for utilizing orthogonal linear polarizations and an microstrip radiator which loaded by close-looped H-shape slot for obtaining dual-band operation. Due to the geometrically different loading effect of the close-looped H-shape slot for each feeding location, the orthogonally linear polarization at dual-band operation of the proposed antenna can be successfully achieved. The proposed antenna theoretically and experimentally demonstrates the vertical linear polarization at the operating frequency of 1.8 GHz and the horizontal linear polarization at the operating frequency of 2.4 GHz, respectively. The simulation and measurement results of the implemented antenna have been in good agreement with the reflection coefficients, radiation patterns, and realized antenna gains.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.630-639
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• 1998

In this paper, a T-shaped microstrip feed line is proposed for a better impedance matching to the microstrip slot antenna in a various range of slot widths. It was found that the bandwidth of this antenna is proportional to the slot width. It was also found that the radiation resistance of this feed line structure is quite constant and low regardless to the slot width. A slot antenna with T-shaped microstrip feed line is analyzed by using the FDTD method. At first, the propagation process of the reflected wave and the electric field distribution in the time domain is calculated respectively. The antenna parameters also are optimized to get maximum band width, return loss, input impedance, and radiation pattern in the frquency domain by Fourier transforming the time domain results. From the computed results, the optimum slot antenna is designed and fabricated. When the slot width is 16 mm, approximately 35% of bandwidths are obtained without a matching circuit. These computed results using FDTD method were in relatively good accordance with the measured values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2823-2830
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• 2014

The antenna miniaturization technique involves the increment of the electrical length of the resonator the variation of the physical appearance of the antenna. The most typical method of size reduction is designing helical antenna, meander antenna, and fractal antenna. Size reduction using fractal antenna is proposed in this paper. Fractal koch curve has been etched in microstrip patch antenna to downsize the antenna at ISM (Industrial Scientific and Medical) frequency band of 2.45 GHz koch curve microstrip patch antenna ha FR4 epoxy substrate with dielectric constant 4.7, loss tangent equal to 0.02 and dielectric high of 1.6 mm. The designed antenna is fabricated using etching process. The fabricated antenna has return loss of 2.45 GHz, VSWR of 1.1492, and impedance is matched to $46{\Omega}$.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.461-466
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• 2019

In this paper, we have studied the improvement of gain and bandwidth characteristics by using double feeding and L-shaped inset feed line matching circuit in microstrip stacked patch antenna which is widely used to broaden the gain of general microstrip antenna. The proposed structure is composed of two feeding edges of the main patch antenna, each of them are connected to a feeding line having an L shaped inset feeder. And the parasitic patch is placed at a proper distance above the main patch. The size of the main patch is designed so that the resonance frequency is close to the center frequency of the target frequency band. The experimental results show that the bandwidth was increased more than 180MHz in the 2.3-2.7 GHz band, which is more interesting than the single feed, and the gain improvement of 2.5dBi was obtained at 2.7GHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.37-42
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• 2022

A high-performance wideband transition from microstrip to waveguide is proposed. This transition is designed by consideration of gradual field transformation and optimal impedance matching between microstrip line and fin-line. Clear design guidelines of proposed transition using fin-line taper with offset DSPSL (double-sided parallel stripline) are provided to determine the transition shape and the transition length. The fabricated transition exhibits less than 0.67 dB insertion loss per transition for frequencies from 85 to 108 GHz, and less than 1 dB insertion loss from 83 to over 110 GHz. Proposed transition is expected compact radar and various applications.