• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.107-116
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• 2001

In this thesis, characteristics of compact PIFA are analyzed for operation in dual frequencies (dual-PIFA) as variety of parameters. The antenna is composed of two patches. These are operated in high frequency and low frequency. The dimension of experiential antenna is fixed for attaching at the handset. The variable parameters are dimension of small patch, length of shorting strip and dimension of folded conductor plate, the frequencies are 900 MHz and 1800 MHz. The compact antenna is implemented with 2-layer type, electric field intensities and radiation patterns are simulated. In order to analyze characteristics of a performance as variety of parameters, FDTD method is used.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1620-1627
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• 2001

In this paper, a broadband microstrip antenna for PCS and IMT-2000 service is designed. To obtain the broadband characteristics of an antenna, we utilized the multi-layered structure composed of two foam material layers, parasitic element and aperture coupled feeding network. The broadband characteristic is obtained by changing the size of parasitic element and the height of foam materials. In addition to that, the usage of metal layer at the distance of λ/4 from feed-line, back radiation is reduced. The bandwidth of a single element for VSWR less than 1.3 is about 550MHz. The bandwidth of a designed 1$\times$4 array antenna for VSWR less than 1.3 is about 460MHz. The gain of a designed array antenna is about 11.15∼12.15dBi and the front-to-back ratio is about 30dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.165-172
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• 2019

Using two or more coaxial lines, if one port is connected in series and the other port is connected in parallel, it can be implemented the wideband transmission line transformer(TLT). Because the wideband TLT utilizes the outer conductor of the coaxial line, it is difficult to predict the characteristics. In this paper, based on the analysis for the transfer characteristic(S21) according to the loss of the each line in ${\lambda}/4$-microstrip line TLT, the operating characteristic of the fabricated wideband 4:1 TLT using two $25{\Omega}$-coaxial lines is investigated. The fabricated wideband TLT shows the notch characteristic in which the transfer signal sharply decreases at ${\lambda}/4$ frequency of the coaxial line and has a value within -0.2dB of the transfer characteristic(S21) in $0.06{\sim}0.2{\lambda}$ frequency range of the coaxial line. This transfer characteristics(S21) can change the operating frequency range slightly and set the optimum transfer characteristic(S21) at the desired frequency by changing the length of the microstrip line.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.447-452
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• 2023

In this paper, gain enhancement of a double dipole quasi-Yagi antenna using a meanderline array structure was studied. A 4×1 meanderline array structure consisting of a meanderline conductor- shaped unit cell is located above the second dipole of the double dipole quasi-Yagi antenna. It was designed to have gain over 7 dBi in the frequency range between 1.70 and 2.70 GHz in order to compare the performance with the case using a conventional strip director. As a result of comparison, the average gain of the double dipole quasi-yagi antenna with the proposed meander line array structure was larger compared to the case with the conventional strip director. A double dipole quasi-Yagi antenna using the proposed meanderline array structure was fabricated on an FR4 substrate and its characteristics were compared with the simulation results. Experiment results show that the frequency band for a VSWR less than 2 was 1.55-2.82 GHz, and the frequency band for gain over 7 dBi was measured to be 1.54-2.83 GHz. The frequency bandwidth with gain over 7 dBi increased, and average gain also slightly increased, compared to the conventional case using a strip director.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.904-911
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• 2011

This paper deals with transmission characteristics of a new dual resonant structure for designing waveguide band-pass filter. The structure which has a pass-band between two adjacent stop-bands in a single body consists of circular ridged aperture and four armed conducting patch. The dual resonant behavior of the structure can be represented by a combination of LC series and parallel resonant circuits. Also these resonant properties can be easily controlled by varying the geometry of the aperture and four armed conducting patch. Actually, the structure is fabricated on the microstrip substrate by use of etching technique so that it is formed an iris type resonator which can be easily put into the transverse plane of the waveguide. We use WR-90 standard waveguide, adapters, and VNA(vector network analyzer) to measure the resonant characteristics of the structure. It is very useful to design and to improve the cutoff skirts characteristics in the waveguide band-pass filter design area.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.4
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• pp.279-285
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• 2017

In this paper, the resonator with a parallel plate capacitor is newly proposed around sub-microwave frequency band and applied to earlobe for non-invasive glucose monitoring the human biological tissue. The capacitor including the earlobe as dielectric material is connected to inductive slot in the ground plane of the microstrip line. Based on the simulation, one port resonator circuit is designed and fabricated as a prototype. Three step glucose concentration levels(0, 250, 500 mg/dL) was tested, and its reflection coefficients($S_{11}$) were measured. Owing to high Q resonator more than 100, resonant frequency shift of about 9 MHz per glucose level of 250 mg/dL has been successfully measured. This proves that the proposed sensor is applicable to a blood glucose sensor.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.913-919
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• 2006

In this paper, TE(transverse electric) scattering problems by a resistive strip grating over grounded dielectric multilayers according to the strip width and grating period, the relative permittivity and thickness of dielectric multilayers, and incident angles of a TE plane wave are analyzed by applying the FGMM(Fourier-Galerkin Moment Method) known as a numerical procedure. The induced surface current density is simply expanded in a Fourier series by using the exponential function as a simple function. Generally, the relected power gets increased according as the relative permittivity and thickness of dielectric multilayers gets increased, the sharp variations of the reflected power are due to resonance effects that take place and were previously called wood's anomallies$^{[7]}$. To verify the validity of the proposed method, the numerical results of normalized reflected power for the uniform resistivity R = 0 as a conductive strip case show in good agreement with those in the existing paper.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.198-204
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• 2006

In this paper, TE(transverse electric) scattering problems by a resistive strip grating on a grounded dielectric plane according to the strip width and grating period, the relative permittivity and thickness of dielectric layer, and incident angles of a TE plane wave are analyzed by applying the FGMM(Fourier-Galerkin Moment Method) known as a numerical procedure. The induced surface current density is simply expanded in a Fourier series by using the exponential function as a simple function. The reflected power gets increased according as the relative permittivity and thickness of dielectric multilayers gets increased, the sharp variations of the reflected power are due to resonance effects were previously called wood's anomallies[7]. To verify the validity of the proposed method, the numerical results of normalized reflected power for the uniform resistivity R = 0 as a conductive strip case show in good agreement with those in the existing paper.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.21-26
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• 2019

In this paper, TE(transverse electric) scattering problems by a resistive strip grating between a double dielectric layer are analyzed by using the PMM(point matching method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the resistive boundary condition is applied to analysis of the resistive strip. The numerical results for the normalized reflected and transmitted power are analyzed by according as the width and spacing of resistive strip, the relative permittivity and thickness of the double dielectric layers, incident angles, and uniform resisitivity. Typically, the reflected power for the conductive strip increased as the value of the relative dielectric constant increased, the reflected power for the resistive strip with uniform resistivity decreased as the value of the resisvivity increased. The numerical results for the presented structure of this paper are shown in good agreement compared to those of the existing papers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.1
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• pp.103-107
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• 2024

This paper is a study on a triangle patch antenna using a rectangle slot and strip conductor. The length and spacing of the slot were adjusted to confirm the characteristics of the triangle patch antenna with rectangle slot, and the area and shape of the radiation patch were changed to triangle, rectangle, and hexagon for impedance matching. The HFSS simulator was used to check the antenna parameter characteristics, and the antenna size was 26 mm ×26 mm. In this proposed antenna, the simulation frequency range with VSWR of 2 or less was 5.27 to 6.24 GHz. The bandwidth was 970 MHz. The frequency range of the fabricated antenna was 5.24 to 6.38 GHz, and the bandwidth 1140 MHz. The maximum radiation gain is 5.01 dBi. It was confirmed that all radiation patterns had directional characteristics.