• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.888-895
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• 2004

This paper proposes new miniaturization method of parallel coupled line filter by using capacitors and grounding. Proposed method can reduce resonator size by using only a small number of capacitor and grounding of parallel coupled line filter which is conventional in field of RF filters because of its design and fabrication simplicity. This paper applies the miniaturization method of transmission line and parallel coupled line to parallel coupled line filter, and presents that grounding can reduce the number of shut capacitors. Presented miniaturized method has merits of miniaturization of parallel coupled line, harmonic suppression, and improvement of high frequency skirt with harmonic suppression. For verification of proposed method, this paper presents a hairpin filter, which has 900 MHz center frequency and 10 % FBW, miniaturized to λ/4 by proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.157-158
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• 2014

In this paper, a design method for a compact CPW-fed slot antenna using SRRs(split-ring resonators) is studied. The structure of the proposed slot antenna is a rectangular slot antenna loaded with SRR conductors inside the slot to reduce the antenna size. Optimal design parameters are obtained by analyzing the effects of the gap between the SRR conductors and slot, and the width of the SRR conductors on the input reflection coefficient characteristic. The optimized compact slot antenna operating at 2.45 GHz band is fabricated on an FR4 substrate with a dimension of 36 mm by 30 mm. The length of the proposed compact slot antenna is reduced by 14.3% compared to that of a conventional rectangular slot antenna. Experiment results show that the antenna has a desired impedance characteristic with a frequency band of 2.4-2.49 GHz for a VSWR < 2.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1706-1711
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• 2013

This paper presents the filter of a resonator comprising a shorted open gap ring(SOGR) and interdigital lines. The proposed filter has the ultra wideband characteristic operating from 3 GHz to 10.5 GHz. In order to achieve the remarkable improvement in the size-reduction of the overall filter structure, only one cell of the SOGR with the inter-digital lines is adopted. It is shown that this filter has the size of $18mm{\times}15mm$ using a metamaterial, the fractional bandwidth over 100%, the insertion loss much less than 1dB, an acceptable return loss performance in the results.

• 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 Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.300-305
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• 2012

In this paper, a miniaturized bow-tie monopole UWB antenna with band rejection characteristic is proposed. To miniaturize the proposed antenna, a perfect magnetic wall(PMW) condition is applied to primitive bow-tie monopole antenna. An uneven ground patch, a tapered feeding structure and a edge-chopped main patch are adapted for impedance matching. A quater-lambda slot resonator is inserted at main patch to prevent interference in UWB band from another band. The proposed antenna is fabricated on Taconic RF60-A substrate with relative permittivity of 6.15. The size of the proposed antenna is $30.0{\times}39.7mm^2$, which is only 45 % of the conventional bow-tie monopole antenna. The proposed antenna covers full UWB band with return losses less than -10 dB and has band stop characteristic in 5 GHz WLAN band. The maximum gains are within -1.0~5.0 dBi, the group delay variations are within 1.0 ns and the radiation patterns show directivity characteristics in x-y plane.

• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.415-420
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• 2007

In this paper, we have designed and fabricated a new type of bandpass-filter that used rectangular ring and interdigital capacitive feeding-structure. The filter is applied the modified rectangular ring and interdigital capacitive feeding-structure in patch, which reduce rho size of filter and IEEE 802. 11 correspond to wireless LAN domain(2.45GHz and 5.2GHz) for operating. As a result, the design and fabrication process of the filter become simple and the size of it is reduced more than 60% compared with RF filter are available conventional PEMBF(Parallel Edge-coupled Microstrip Bandpass Filter) of accounted circuit by minimum stage, measurement result of fabricated filter, center frequence is down 2.408GHz and 5.075GHz. input return loss is -39.169dB at 2.408GHz, -40.922dB at 5.075GHz. insertion loss is -0.437dB at 2.408GHz, -1.669dB at 5.075GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.9
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• pp.956-963
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• 2002

A linearly polarized folded type and H-shape slit folded type microstrip patch antenna at GPS(center frequency:1.575 GHz) were designed and fabricated by folding a conventional single $\lambda_{g}/2(\lambda_{g}:wavelength)$ rectangular patch a half along the length direction at the center of patch and inserting ground plane in the middle. As a result, two types of omnidirectional radiation patterns for E-plane (for zx-plane) in the direction of the length of patch and H-plane (for xy-plane) have been acquired. The experimental results show that the average gains of folded type and slit folded type for omnidirectional E-plane and H-plane are -1.5 dBd (-2.4 dBd) and -3.27 dBd(-2.5 dBd). Slit folded type microstrip patch antenna was more miniaturized than folded type microstrip patch antenna by 27.5 %. In case of slit folded type antenna, average gains of omnidirectional radiation pattern for E & H-plane are almost same.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.59-64
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• 2009

In this paper, the design of a new bandstop filter with an ultra-wide stopband is proposed using the metamaterial CRLH-TL. Instead of conventional periodic structures and multi-staged CRLH-TLs, extremely small one-cell type is adopted to circumvent the setbacks of conventional filters such as the lengthened ${\lambda}_g/2$-resonator ones or alternating impedance lowpass filter, and relatively slow skirt. Besides, for a very broad stopband, a strong coupling structure including stepped impedances is suggested and the zero-order resonance is made for effective size-reduction. The validity of the proposed design is proven through the fabrication and measurement, showing the overall size less than ${\lambda}_g/10$, the stopband wider than 12 GHz, 0.7 dB of the insertion loss.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.12
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• pp.1402-1407
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• 2007

This paper presents a new design method of the Ultra-Wide-Band BandPass Filter using the CRLH-TL(Composite Right- and Left-Handed Transmission-line) having the Metamaterials' properties. Instead of the periodic type or many cells of the CRLH-TL, only the unit cell is used to miniaturize the target component, which can not be realized by the conventional quarter guided-wavelength resonator-based filters. Particularly, the strong coupling essential to the Ultra Wide Band is enabled by the interdigital coupled lines between the grounded stubs. The proposed design scheme is validated by the electromagnetic simulation and measurement of the fabricated filter which shows the total size of 'the guided-wavelength/9.4', the 100 % fractional bandwidth for the UWB, the insertion loss of less than 1 dB and the flat group-delay.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1447-1453
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• 2010

In this paper, the design and the fabrication of dual-band bandpass filter using two dual-mode resonators is presented. Dual-mode resonator using a short stub is miniaturized by inter-digital capacitor and stepped impedance. Two dual mode resonators are designed to have different resonant frequencies, one for the lower passband and the other for the upper passband. Transmission zero is positioned at low or high rejection bands with a sharp skirt characteristic. Dual-band operation can be achieved using dual feeding structure. For WLAN, the proposed filter at 2.45/5.25 GHz is designed and fabricated. The size of the filter is as compact as 1$10.83\;mm{\times}5.3\;mm$.