• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.206-216
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• 2000

In this paper, the linear tapered slot(LTS) antenna and linear constant tapered slot(LCTS) antenna are optimized for millimeter-wave antenna by the finite difference time domain(FDTD) method and then fabricated and measured. The microstrip-to-slot transition is proposed with the widen $\lambda$/4 open stub as feeder for wide bandwidth of 16.5GHz($VSWR\leq2$). The results of the calculation and measurement, the bandwidth of LTS antanna is 8.3GHz(26.47%) and 7.1792GHz(22.4%) respectively. Also, the bandwidth of LCTS antenna is 8.1GHz(26.47%) and 6.3243GHz(20.43%) respectively.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.10 s.89
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• pp.1005-1010
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• 2004

An analysis method of slot-coupled microstripline to waveguide transition is presented to developed a simple but accurate equivalent circuit model. The equivalent circuit consists of an ideal transformer, microstrip open stub, and admittance elements looking into a waveguide and a half space of feed side from a slot center. The related circuit element values are calculated by applying the reciprocity theorem, the Fourier transform and series representation, the complex power concept, and the spectral-domain immittance approach. The computed scattering parameters are compared with the measured, and good agreement validates the simplicity and accuracy of the proposed equivalent circuit model.

• ETRI Journal
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• v.43 no.6
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• pp.957-965
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• 2021

A miniaturized wideband band-pass filter with a 3-dB fractional bandwidth of 109.3% (1.53 GHz to 5.22 GHz), high out-of-band attenuation greater than 25 dB, and wide upper stopband up to 14 GHz is proposed. The design consists of a dual-composite right/left handed resonator, embedded open-circuited stub, and a pair of quarter-wavelength short-circuited stubs. These elements are coupled in the near distance to form a miniature filter with a compact occupied area of 0.21 λ_g×0.19 λ_g (≈ 0.013 cm²). The optimized filter has multitransmission poles in the passband, substantially improving the return loss and insertion loss characteristics. The behavior of the passband and stopband is verified against the results of a lumped element model and matrix analysis with a full-wave moment-based analysis and actual measurements. The results of this verification and a comparison with the performance of filters in other references indicate that the proposed filter is very efficient and applicable to compact microwave systems.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.595-600
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• 2023

In this paper, a modified equations of the T-equivalent circuit of the transmission line with the arbitrary electrical length is suggested. The suggested equations can be calculated without limitation of the equal branch-line. So, a modified T-equivalent circuit can be made with the arbitrary position of the open-stub. Also, the modified T-equivalent circuit can be applied in the arbitrary electrical length and impedance of the transmission line. For example, the λ/4 impedance transformer is converted with 4 divided T-equivalent circuit. The converted λ/4 impedance transformer has the size reduction ratio of 39.4%.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.343-348
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• 2014

This paper suggested a theoretical approach and an implementation for the design of an unequal Wilkinson power divider with a high dividing ratio operating at two-frequencies. The T-section transmission lines and the two-section of Monzon's theory are proposed to operate a dual-band application. To achieve the high dividing ratio divider, the high impedance line using a T-shaped structure and low impedance lines with periodic shunt open stubs are implemented. For the validation of this divider, a dual-band power divider with a high dividing ratio of 5 is simulated and measured at 1 GHz and 2 GHz. The measured performances of the divider are in good agreements with simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.508-514
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• 2013

Substrate integrated waveguide(SIW) constructed by two metal planes and conductive vias in a dielectric substrate, have all the conductors connected each other and hence, cannot be biased by DC sources. We propose a new folded corrugated substrate integrated waveguide(FCSIW) that can be DC-biased. Since the proposed FCSIW replaces the SIW conducting vias by folded open subs, it can supply the DC sources. The FCSIW has better transmission characteristics and 30 % less width than the common corrugated substrate integrated waveguide(CSIW) having a serious leakage generation problem. The FCSIW shows better insertion loss(1.49 dB) compared with that(3.08 dB) of the CSIW measured for 154 mm length devices and averaged at 9~15 GHz frequency band. No leakage has been observed from crosstalk measurements of the FCSIW.

• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.481-487
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• 2008

Ship's wireless LAN was in the limelight as equipment of ease, cost reduction, various func tion al i ty. In the paper, a dual-bandpass filter for wireless LAN has proposed, which was designed by using dual-mode square loop resonator with square patch in compliance with 2.4 GHz and 5 GHz band of wireless LAN. The dual-bandpass filter could be designed by adjusting sizes of one perturbation element and three of reference elements in compliance with the frequency bands of 2.4 GHz and 5.8 GHz, Furthermore, new dual-bandpass filter was also designed by adjusting stopband of using open stubs in compliance with the frequency bands of 2.4 GHz and 5.2 GHz. The measured results for the fabricated dual-bandpass filters agreed well with the simulated ones, and hence, it was confirmed that the proposed design method is valid.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.486-493
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• 2010

This article introduces a novel ultra wideband(UWB) bandpass filter(BPF) with sharp roll-off characteristics in stripline structure. The UWB characteristic is basically obtained from capacitive coupled cross resonator. The resonator has ${\lambda}/2$ length. And at the center of the resonator, two stubs are loaded, one is a ${\lambda}/8$ short-circuited stub and the other is a ${\lambda}/8$ open-circuited stub. The two stubs provide two attenuation poles at lower and upper cutoff frequencies. For input and output lines, two identical capacitively coupled lines have been installed to suppress the unwanted signals in the lower and upper stopbands. The filter has been designed for the U.S. UWB band(3.1~10.6 GHz) with two transmission zeros at 2.4 and 11.1 GHz. The filter has been realized with Low Temperature Core-fired Ceramic(LTCC) green tape which has the dielectric constant of 7.8. Measurement results agree well with HFSS simulation results. Insertion loss less than 0.7 dB and return loss better than 14 dB in the pass band have been measured. The group delay in the center frequency is 0.27 ns and the group delay variation within pass band is less than 0.5 ns. The size of the filter is $6{\times}18{\times}0.6\;mm^3$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.283-291
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• 2012

In this paper, a compact antenna is designed for the UWB lower half-band WVAN Gbps data-rate transceiver. The proposed antenna broadens the bandwidth less than -10 dB by placing the ring stubs and an open stub on the rectangular monopole above the partial ground and creating multiple resonant current paths. The designed antenna goes through the electromagnetic simulation and is fabricated and the implemented antenna has the characteristics of the return loss lower than -10 dB, the antenna gain greater than 5 dBi, and the efficiency over 80 % in the UWB lower half-band ranging from 3.197 GHz to 4.732 GHz. Therefore, it is thought that the proposed antenna is suitable for the size-reduced and excellently performing wireless communication transceiver.