• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.4
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• pp.257-262
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• 2015

In this paper, the split-ring DGS resonator is proposed and its equivalent circuit are analyzed to design the low pass filter. Compared with the conventional dumbell DGS cell, this structure has a flat fluctuation in low frequency range and a sharp slop at edge frequency. The out-band suppression of the SRR-DGS cell can be improved by placing the open stubs on the conductor line which operates as parallel capacitances. Making use of equivalent circuit analytical method, the characteristics of the improved SRR DGS cell are investigated and applied to design compact low pass filter, which has a low in-band loss, sharp slop and high suppression of more than 35dB within a wide out-band frequency range. The dependence of the transmission characteristic on the dimension of a split ring, such as side-length and split-gap, is analyzed in detail. In addition, an improved SRR DGS cell model with open stubs loaded on the conductor line is then presented to improve the out-band suppression. By using the equivalent-circuit analytical method, an S-band microstrip low-pass filter with perfect low-pass characteristic and high out-band suppression is designed and fabricated.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.467-474
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• 2019

In this paper, we studied a method for a broadband stacked patch antenna structure which is widely used for bandwidth improvement. The characteristics according to the distance between the two patches were analyzed and the impedance matching was optimized by connecting parallel open stubs to the main patch feed line. The shunt matching stub is inserted underneath the parasitic patch and so it does not require additional space, which enables the proposed antenna structure to be advantageous in miniaturizing antenna. The effects of the various parameters on the antenna performance are examined, and we introduced the design procedure for the proposed antenna to operate in the frequency range of 2.3~2.7GHz. Experimental results show that the bandwidth of the proposed antenna is about 480MHz with 2.27~2.75GHz bandwidth. And the antenna gain was 5.8dBi at 2.3GHz and 7.8dBi at 2.6GHz within the bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2A
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• pp.147-152
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• 2005

In this paper, we have proposed a novel DGS(Defected Ground Structure) resonator and has designed the band -pass filter using the proposed ${\subset}$ stub-I type DGS resonator. This structure has strong advantages that can vary the retune loss at the passband freely and also can easily tune the attenuation pole frequency at the stopband. The bandpass filter can be made more smaller than the existing filters and be used to find the various applications for eliminating the harmonics and spurious mode at IMT-2000 band.

• Journal of electromagnetic engineering and science
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• v.15 no.1
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• pp.31-36
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• 2015

The design of a new compact band-pass filter is proposed, which is based on the microstrip composite right- and left-handed transmission- line (CRLH-TL) structure. Particularly, the interdigital coupled (IDC) lines of the CRLH geometry are proposed to be parted by inserting open stubs to meet the specifications on the passband. In addition, there is another pair of stubs to complete the design in a limited space. These are considered in the TL-based analysis and the design parameters are calculated by genetic algorithm optimization. The measurement is shown to be acceptable and agreeable with the circuit and electromagnetic field simulations. In addition, the zerothorder resonance (ZOR) phenomenon is verified.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1294-1302
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• 2008

A design approach for a radiation element of dual polarization, which can be implemented in the waveguide structure, is proposed. For minimization of the radiating element, the ridged waveguide type is used and for dual polarization, the microstrip type of printed dipole structure is additionally installed inside the waveguide. In order to validate the design approach, $1{\times}4$ array antenna is fabricated and its performances such as return loss, co-polarization coupling between adjacent channels, and radiation patterns are investigated. Theory and experiment are observed to be in good agreement. The radiating structure is thought to be a useful one in an application to the phased array antenna system, in particular, requiring dual polarization characteristics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1633-1640
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• 2016

In this paper, we propose a open-ended rectangular microstirp patch antenna with fork-shaped feeding structure. This antenna extends the effective bandwidth by transforming single or multi resonant frequency and is designed planar monopole structure with microstrip line to satisfy the WLAN bands (2.4 - 2.484, 5.15 - 5.35, 5.25-5.825 GHz). The substrate is printed in 0.8 mm thickness on an FR-4 board. A commercial 3D simulation tool was used to analyze surface current and electromagnetic field distribution in order to analyze the operation mode and reconfiguration principle of antenna. According to the lengths of individual patches, simulated reflection loss was compared to obtain optimized values. When it was designed with the optimized values, it satisfied WLAN bands (2.380 - 2.710, 4.900 - 5.950 GHz), if the switch is off, and 2.4 WLAN band (2.380 - 2.710 GHz). From the fabricated and measured results, measured results of return loss, gain and radiation patterns characteristics displayed for operating bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.463-470
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• 2015

In this paper, a new dual-band bandpass filter(BPF) that has resonators and feed lines with Stepped-Impedance Resonator(SIR) structures is proposed. Feed lines with SIR structure provide maximum magnetic field points which occur at the same locations of the input and output feed lines, so the insertion loss of BPF was reduced. Applying the SIR structure to the BPF for the first passband improves rejection characteristics between the first passband and the second passband. It reduces the coupling between the BPF for the first passband and the BPF for the second passband, so it makes the dual-band BPF more compact. The proposed design method provides independent changes of both the center frequency and the bandwidth for each resonator, and also improves filtering characteristics. The validity of the proposed design method is confirmed by comparisons between the designed parameters and the measured results satisfying WLAN specifications.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.463-468
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• 2023

In this paper, we proposed reconfigurable dual polarization patch array antenna that can select two polarizations(Vertical, RHCP) using defected ground structure and Pin diode. The proposed antenna was designed arranging a circular polarization patch antenna implemented with a square microstrip patch and two slots 3x3 at 25.8mm placed, a half-wavelength of 5.8 GHz. Conect the pin diode and the capacitor to the slot diagonally placed on the ground of each antennas, and select polarization using the open/short operating according to the application of DC voltage to the pin diode. As a result of the design, the gain of the antenna is 11.7 dBi at vertical polarization and 11.6 dBic at RHCP. The axial ratio is 20.3 dB at 1.8 dB vertical polarization at RHCP. Mutual Coupling is Maximum to -20.8 dB for vertical polarization and Maximum to -30.1 dB for RHCP.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.515-525
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• 2014

In this paper, we present a design and implementation of a Voltage-tuned Planar Composite Resonator Oscillator(Vt-PCRO) with a low phase noise. The designed Vt-PCRO is composed of a resonator, two phase shifters, and an amplifier. The resonator is designed using a dual mode SIW(Substrate Integrated Waveguide) resonator and has a group delay of about 40 nsec. Of the two phase shifters (PS1 and PS2), PS1 with a phase shift of $360^{\circ}$ is used for the open loop gain to satisfy oscillation condition without regard to the electrical lengths of the employed microstrip lines in the loop. PS2 with a phase shift of about $70^{\circ}$ is used to tune oscillation frequency. The amplifier is constructed using two stages to compensate for the loss of the open loop. Through the measurement of the open loop gain, the tune voltage of the PS1 can be set to satisfy the oscillation condition and the loop is then closed to form the oscillator. The oscillator with a oscillation frequency of 5.345 GHz shows a phase noise of -130.5 dBc/Hz at 100 kHz frequency offset. The oscillation power and the electrical frequency tuning range is about 3.5 dBm and about 4.2 MHz for a tuning voltage of 0~10 V, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1264-1271
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• 2009

In this paper, the chip slot antenna which is used for mobile devices and designed for multi-band is proposed. The proposed antenna is comprised of a chip antenna(10 mm$\times$20 mm$\times$1.27 mm) and a system circuit board(30 mm$\times$60 mm$\times$0.8 mm). The chip slot antenna is mounted on the system circuit board and the end of F-type strip line which is patterned on the chip antenna is connected by a via with a ground plane of the system circuit board. So, a chip antenna radiates effectively the energy by transition between a microstrip line of the system circuit board and a open slot structure of the chip antenna. In the results of proposed antenna, impedance bandwidth of 3:1 VSWR(-6 dB return loss) is 1.98 GHz(1.61~3.59 GHz) and 0.8 GHz(5.2~6 GHz). So, it can cover multi-band of DCS, PCS, UMTS, WLAN. The proposed antenna can be applied to mobile devices.