• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.22-25
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• 1987

New measurement method of coupled transmission line characteristics is described. This method presents precision calculated values of even- and odd-mode impedances and effective dielectric constants of mictostrip parallel coupled lines from the scalar quantities obtained by transmission coefficients at two different resonance frequencies. Measured impedances and effective dielctric constants are good agreement with predicted values.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.114-120
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• 2008

This paper proposed the band pass filter(BPF) with feeding structure using $\pi$-type transmission line by means of transforming the input/output coupled-lines of the half wavelength parallel coupled-line BPF into K-inverter, then substituting $\pi$-type transmission line equivalence for K-inverter. The proposed method supplies solution with what the half wavelength parallel coupled-line BPF's input/output coupled-lines are realized. Also it can quite reduce efforts and time needed to optimize filter performance when is compared to reported method using tapped line structure because formulas is very simple and accurate. On the basic of the proposed method, the BPF with feeding structure using $\pi$-type transmission line has been designed and fabricated. The validity of proposed method was proven by the measured result.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.387-392
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• 2014

In this paper, a size-reduced Wilkinson balun with wide harmonic-suppressed band is presented. An accurate analysis of the parallel coupled line with an open stub (PCL-OS) is carried out. The PCL-OS structure shows excellent low pass filter and harmonic-suppression characteristics, which is useful for designing a low pass filter unit cell (LUC) with a reduced size. The designed Wilkinson balun at a 2.45 GHz center frequency not only shows an excellent harmonic suppression including the 5th harmonics up to 14 GHz over 15 dB, but it also has an area reduced to 48% of the conventional one.

• ETRI Journal
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• v.31 no.3
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• pp.254-262
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• 2009

This paper presents a novel simple filter design method based on a parallel short-ended coupled-line structure with capacitive loading for size reduction and ultra-broad rejection of spurious passbands. In addition, the introduction of a cross-coupling capacitor into the miniaturized coupled-line can create a transmission zero at the second harmonic frequency for better frequency selectivity and attenuation level. The aperture compensation technique is also applied to achieve a strong coupling in the coupled-line section. The influence of using the connecting transmission line to cascade two identical one-stage filters is studied for the first time. Specifically, such a two-stage bandpass filter operating at 2.3 GHz with a fractional bandwidth of 10% was designed and realized with low-temperature co-fired ceramic technology for application in base stations that need high power handling capability. It achieved attenuation in excess of -40 dB up to $4f_0$ and low insertion loss of -1.2 dB with the size of 10 mm ${\times}$ 7 mm ${\times}$ 2.2 mm. The measured and simulated results showed good agreement.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.54-60
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• 2008

In this paper, the novel method is proposed to realize the parallel coupled line band pass filter using defected ground structure(DGS) inverter. This method provides simple solution which easily resolves the limit of line width happened due to high impedance on the occasion of designing filter composed of line inverter. On the basis of the proposed method and conventional method, the band pass filters haying 13.3% fractional bandwidth were designed and implemented. The measured data of two filters show usually good agreement with each other, but on the other hand the length of proposed filter become shorten about 15mm and the width of inverter line was expanded two times or more in comparison with conventional filter.

• Journal of electromagnetic engineering and science
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• v.13 no.1
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• pp.34-37
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• 2013

This paper presents a novel ultra-wideband (UWB) antenna that rejects narrow and broad bands and is suitable for wireless communications. The base of the proposed antenna has a circular patch that can cover the UWB frequency range (3.1~10.6 GHz). The interference issues caused by co-existence within the UWB operation frequency are overcome by a design that uses a parallel-coupled asymmetric dual-line with a circular monopole antenna. The proposed antenna showed a stable radiation pattern, realized gain and reflection coefficient lower than -10 dB across the UWB operation bandwidth except for 5.15~5.85 GHz and 7.25~8.4 GHz. The fabrication, simulation, and measurement results obtained for the proposed antenna were in good agreement with the expected values.

• ETRI Journal
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• v.44 no.2
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• pp.260-273
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• 2022

This study presents a novel multilayer structure of parallel coupled-line bandpass filtercentered at 2.42 GHz with a fractional bandwidth value of approximately 19.4%. The designed filter can suppress harmonics with an appropriate frequency response by incorporating different techniques based on the multilayer technique. A combination of different techniques such as radial microstrip stubs and defected ground structure (DGS) and defected microstrip structure techniques are employed to suppress harmonics up to 5f₀. These techniques are used in two layers to suppress up to 5f₀. In addition, in this study, the effects of different parameters, such as the width of slot-line DGS, the angle of diagonal line slots in the upper layer, and the air gap between the two layers on the filter performance, are investigated. To verify the correct circuit operation, the designed filter is implemented and tested. The measurement results of the proposed filter are compared with the simulation results.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.73-77
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• 2018

This paper proposes a dual-band bandpass filter using stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with parallel coupled lines (PCLs) that have interdigital and comb-line shorted ends. The central PCLs build an upper passband and a transmission zero, and the two U-shaped SIRs build a lower passband. Four resonators and coupling structures are theoretically analyzed to derive its scattering parameters. A novel dual-band bandpass filter is designed and fabricated using the induced scattering characteristics. The measured results show that the fabricated dual-band bandpass filter has an insertion loss of less than 1.02 dB in the lower band of 2.45 GHz and of 3.01 dB in the upper band of 3.42 GHz, and a band-to-band isolation of more than 40 dB, from 3.14 to 3.2 GHz.

• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.309-315
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• 2019

This paper proposes an implementation of unequal power divider with 1:3 and 1:4 splitting ratio in multi-section structure using CPW and offset coupled transmission line. The power divider consists of a multi-section transmission line and a circuit with parallel capacitors and resistors. A multi-section transmission line was implemented by decomposing a ${\lambda}/4$ single transmission line terminated by an arbitrary impedance and converging it with a multi-section transmission line shorter than $90^{\circ}$ electrical length, and RC parallel circuits were connected between transmission lines to obtain reflection coefficient of output port and isolation characteristics between the output port. In this way, it was confirmed that the transmission lines at the unequal power divider designed at 2 GHz were shorter than ${\lambda}/4$ and implemented at least 27% less than the conventional ones, and that the broadband characteristics could be obtained.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.57-62
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• 2023

This paper proposes a tri-band bandpass filter using dual-mode stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with open stubs and parallel coupled lines (PCLs) that have inter-digital and comb-line shorted ends. Two U-shaped SIRs with open stubs build the first and third passband, and the central PCL resonators build the second passband. Five resonators and coupling structures are theoretically analyzed to derive the scattering parameters of the proposed filter. A novel tri-band bandpass filter is designed and fabricated using the induced scattering parameters. The measured result of the fabricated tri-band bandpass filter shows a good agreement with the simulated one.