• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.361-365
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• 2003

In this paper, we proposed the effective serial connection methodology of PBG resonator with defect mode. We use the big difference of impedance ratio in connection region, for example dual PBG, for serial connection. This method reduces the PBG cells and is able to control the pole of bandpass filters. This result in flexibility in design of bandpass filter. Our PBG bandpass filter is modeled by using the ideal transmission line model. This model is very easy, fast, and effective for PBG structure.

• Journal of electromagnetic engineering and science
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• v.11 no.3
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• pp.186-191
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• 2011

This paper presents a simple and effective method for improving stopband rejection characteristics of previously studied dual-band filters. Small electric couplings were applied to the symmetrically positioned shunt resonators, which divided each transmission zero into two transmission zeros without any effect on passbands. We were able to achieve improved stopband rejection characteristics by these additional transmission zeros. For the filter application, we designed a dual-band filter with improved stopband characteristics using microstrip quasi-lumped elements. The electric couplings that control the location of transmission zeros are controlled by the distance between symmetric open stubs of the filter. The filter was fabricated with a relative dielectric constant of 3.5 and a thickness of 0.76 mm. The fabricated filter has a small size ($14.6{\times}13.2{\times}0.76$ mm) and a low insertion loss when compared with conventional filters.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.523-526
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• 2002

This paper presents the simulation of Au / $Ba_{x}$S $r_{1-x}$ Ti $O_3$(BSTO) / Magnesium oxide (MgO) multi-layered and electrically tunable band-pass filters (BPFs) by using high frequency structure simulator (HFSS). This model is a two-pole microstrip edge coupled filter. The filter was designed fur a center frequency about 5.8 GHz. The tunabillity of the filter is achieved using the nonlinear dc electric-field dependence on the relative dielectric constant of BSTO frroelectric thin film. This work seems very promising for future wireless communication systems....

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2383-2385
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• 2005

In this paper we discuss the design and fabrication of two millimeter wave filters, in bandpass and bandstop topologies for wireless communications applications. The filters are made using a high Q MMIC transmission line, which consists of a 100 micrometers tall, surface micromachined, air filled inverted microstrip structure on a quartz substrate, made by using a JSR THB-151N negative photoresist sacrificial layer mold and electroplating technology. The filter topologies include a new, very compact, four pole, cross-coupled filter, that presents a single transmission zero at the lower side of the passband, which provides a very sharp out of passband rejection at this region.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.71-74
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• 2000

본 논문에서는 무선LAN용으로 사용할 수 있는 마이크로 스트립을 이용한 대역동과 필터를 설계하였다. 기존의 링이나 square loop의 구조를 이용한 공진기와는 다르게 cross loop 와 meander loop의 구조를 이용한 공진기를 혼합한 형태로써 크기가 상당히 줄어든 새로운 구조와 BandPass Filter를 설계하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1991.10a
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• pp.103-106
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• 1991

Spectrum Analyzer is a useful measure instrument to display the distributed power of electrical signal as a function of frequency. It adopts the superheterodyne receiver, which mixes RF with L0 to output IF. So in this paper, two GHz-order microstrip low-pass filters, 2-section wilkinson power divider, and singly balanced diode mixer have been designed and implemented necessary to make the frequency converter applied to RF spectrum analyzer.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.331-334
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• 2003

This letter presents the design and measured performance of bandpass filters based on a stacked-SIR (stepped impedance resonators) configuration with DGS (Defected Ground Structure). An unit DGS configuration is designed and analyzed to show the phase characteristic of proposed slow-wave structure. The SIR filter with DGS has been yielded better stop band and sharper skirt behavior than conventional bandpass filter.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1332-1-1332-4
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• 1998

This paper described design and simulation of the high-Tc superconducting (HTS) microstrip bandpass filter (BPF) on MgO substrate using $Y_1Ba_2Cu_3O_{7-x}$ films that show superconductivity ${at \fallingdotseq}90$ K. Design parameters for the characteristic of the bandpass filter in Ku-band were obtained by approximate design formulas. It used parallel coupled stripline stepped impedance resonators (SIR). Microwave design system, MDS(EEsorf S/W) was used to derive the optimal pattern of the filters and to simulate frequency response. In computer-aided results, optimally designed HTS filters got good performance compared with the gold counter-parts on frequency response $S_{21}$, $S_{11}$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.1-8
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• 2011

In this paper, a microstrip bandpass filter(BPF) with 3 dB bandwidth of more than 50 % at center frequency of 30 GHz was implemented. The implemented BPF is to be used as ASK(Amplitude Shift Keying) transmission and reception filters in IF band for THz transmitter and receiver capable of 10 Gb/s wireless data transmission. The microstrip BPF with ultra-wideband characteristics was implemented using a stepped-impedance lowpass filter(LPF) and a composite quarter-wave short stubs where the LPF is functioning as attenuating the upper stopband and quarter-wave short stubs is functioning as attenuating the lower stopband. The measured results are as follows; the insertion loss is 0.65 dB at 30 GHz, the stopband characteristics are -10 dB and -16 dB at 10 GHz and 50 GHz, respectively, and the passband flatness is ${\pm}0.5$ dB at 20~40 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.11
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• pp.1082-1089
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• 2004

In this paper, miniaturization of an elliptic-response open-loop resonator filter and design flexibility using similarity transformation of the coupling matrix are proposed. Moreover, the filter with wider fractional bandwidth is designed by the proposed method. In order to verify the proposed method, three 4th-order elliptic-response open-loop resonator filters with a relative bandwidth of 4 % at the center frequency of 2.0 GHz are designed. One is realized with constant-width microstrip line resonator and the others are implemented with different-width microstrip line resonator. Compared with the former one, the latter have shown the size reduction of 13 % and 25 %, respectively. Since it may not be possible to implement the resonators with very narrow spacing for the required coupling coefficient filters with two different configurations representing same response characteristic through similarity transformation of the coupling matrix are proposed. From this design flexibility, a filter with a relative bandwidth of 8 % at the center frequency of 2.0 GHz is designed with realizable design parameters.