• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.385-386
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• 2008

In this paper, a simple dual band filter chip is designed with 0603 case size using IPD technology. The dual-band filter achieves high frequency band at 2.5 GHz and low frequency band at 1.8 GHz. The insertion losses in high frequency band and low frequency band are -0.195 dB and -0.146 dB, respectively. The return losses in these bands are -22.7 dB and -22.8 dB, respectively. The simple dual-band filter based on SI-GaAs substrate is designed within die size of about 1.3 $mm^2$.

• 전자공학회논문지A
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• 제33A권4호
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• pp.98-105
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• 1996

The design method of 85 GHz-115 GHz band single side-band filter using the principle of martin-puplett inteferometer is described. It has been designed by this method and also manufactured and tested. From the test results, not only the ratio of image singal rejection of 19 dB is obtained, but also the theoretical and experimental results of center frequency of pass-band and rejection-band show the validity of the theory. This manufactured filter was installed on 100GHz band SiS (superconductor insulator superconductor ) receiver for observing cosmic radio waves and tested. We found that this filter can be used a single side-band as well as double side-band mode. The design method which is presented in this paper can be used a single side-band filter for a heterodyne type sub-milimeter wave receiver.

• 대한전자공학회논문지TC
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• 제46권9호
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• pp.60-65
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• 2009

본 논문에서는 대역통과 여파기와 대역저지 여파기를 하나의 구조로 합성하여 크기 증가 없이 초광대역 특성을 가지면서 Wireless-LAN 대역을 저지하는 대역통과 여파기를 설계, 구현하였다. 대역저지 특성을 얻으면서도 여파기의 크기증가가 없어야 하기 때문에 전송선에 내장된 형태의 오픈 스터브를 사용하였다. 그리고 저역 통과 특성을 얻기 위하여 접지 면에 식각할 수 있는 DGS(Defected Ground Structure) 구조를 이용하였다. 기존의 대역통과 여파기와 저역통과 여파기를 직접 연결하였을 때 보다 크기를 줄일 수 있었다. 측정결과 통과대역은 $2.21GHz{\sim}10.92GHz$ 이고 삽입손실은 최대 0.7dB, 반사손실은 최소 17dB, 군 지연 변화폭은 0.22ns였으며 $5.3GHz{\sim}5.7GHz$의 저지대역을 형성하였다.

• Journal of electromagnetic engineering and science
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• 제11권2호
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• pp.83-90
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• 2011

In this paper, we present the design method for a low-pass type inverter, which can effectively suppress the spurious response associated with band-pass filters. The inverter has a length of ${\lambda}/4$ and employs not only a stepped-impedance configuration but also asymmetrical and bending structures in order to improve frequency selectivity and compactness. The inverter is applied as an impedance/admittance inverter to the ultra-wideband (UWB) band-pass filter. The UWB band-pass filter configuration is based on a stub band-pass filter consisting of quarter-wavelength impedance inverters and shunt short-circuited stubs ${\lambda}/4$ in length. The asymmetrical stepped-impedance low-pass type inverter improves not only the spurious responses, but also the return loss characteristics associated with a UWB band-pass filter, while a compact size is maintained. The UWB band-pass filter using the proposed inverters is fabricated and tested. The measured results show excellent attenuation characteristics at out-band frequencies, which exceed 18 dB up to 39 GHz. The insertion loss within the pass-band (from 3.1 to 10.6 GHz) is below 1.7 dB, the return loss is below 10 dB, and the group delay is below 1 ns.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.168-175
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• 2013

This paper presents compact dual-band WLAN filter and filter module. They were developed by embedding all of the passive lumped elements into a LTCC substrate. In order to reduce the size/volume of the filter and avoid EM parasitic couplings between the passive elements, the proposed filter was designed using a 3rd order Chebyshev circuit topology and J-inverter transformation technology. The 3rd order Chebyshev bandpass filter was firstly designed for the band-selection of the 802.11b and was then transformed using finite transmission zeros technologies. Finally, the dual-band filter was realized by adding two notch resonators to the 802.11b filter circuit for the band-selection of the 802.11a/g. The maximum insertion losses in the lower and higher passbands were better than 2.0 and 1.3 dB with minimum return losses of 15 and 14 dB, respectively. Furthermore, the filter was integrated with a diplexer to clearly split the signals between 2 and 5 GHz. The maximum insertion and minimum return losses of the fabricated module were 2.2 and 14 dB at 2.4 - 2.5 GHz, and 1.6 and 19 dB at 5.15 - 5.85 GHz, respectively. The overall volume of the fabricated filter was $2.7{\times}2.3{\times}0.59mm^3$.

• 한국전기전자재료학회논문지
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• 제11권11호
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• pp.975-983
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• 1998

A duplexer filter operating at 1.9 GHz band for personal communication system is designed and fabricated using $lambada$/4 TEM mode dielectric resonator. The transmitting band pass filter is designed in the type of the elliptic function band rejection filter by 3 dielectric resonators with 5 additional capacitors and 3 inductors. The receiving band pass filter is designed by 3 dielectric resonators with 5 additional capacitors which give additional series resonance. The parameters which are evaluated by design theory are practically applied to the duplexer filter construction and the simulation.

• 전기학회논문지
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• 제61권11호
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• pp.1700-1705
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• 2012

This study is focusing on ripple elimination in the band pass filter. There are generally two design methods in IIR filter design, which are a direct method and an indirect one. The indirect design method that designs the digital IIR LPF using the prototype analog LPF is applied to this study. A Butterworth filter and a Chebyshev filter are the typical prototype analog LPFs. This study shows characteristics of the digital IIR LPFs that are transformed from the prototype analog LPFs. The designed Butterworth and Chebyshev IIR LPFs are also designed as the band pass filters by frequency transformation in order to compare with the proposed cascading Chebyshev BPFs. This study shows frequency characteristics between the transformed IIR BPFs and the proposed cascading Chebyshev BPFs as well. The proposed cascading Chebyshev BPF is designed by cascading the different orders of Chebyshev BPFs. The aspect of the cascading filter is offsetting the ripples to descend them while the pass band ripples of the Chebyshev filter are ascending and vice versa. The designed cascading Chebyshev filter shows the flatness and the sharpness, which represent the advantages of Butterworth filter in the pass band and of Chebyshev filter in the transition band respectively. This result verifies the validity of the designed filter.

• E2M - 전기 전자와 첨단 소재
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• 제9권9호
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• pp.933-941
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• 1996

In this study, the Tx(Transmitting) and Rx(Receiving) band pass filter for personal communication services was constructed and designed using .lambda./4 TEM mode dielectric resonators. Band pass filter was composed of ceramics resonators which has been developed using ($Zr_{0.65}$,$Sn_{0.35}$) $Ti_{1.04}$ $O_{4.04}$ ceramic and Unloaded-Q ( $Q_{o}$) of .lambda./4 TEM mode dielectric resonator with inner hole size 0.9mm and external size 3mm using silver electrode is 354.5 at 1.95GHz. For the band pass filter design and construction, the design theory and simulation results of band pass filter using J-inverter theory have been studied. The parameters which are evaluated by design theory are practically applied to the filter construction and the simulation results are in agreement with the measured results after fine tunnings.s.s.s.s.s.

• 전기학회논문지
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• 제61권1호
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• pp.104-109
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• 2012

In this paper, we propose a way to improve the quality of L-band wireless communication from unfriendly influential factors lying in the neighboring RF bands. The UHF-band system has resonator components and they generate harmonics as the spurious in the L-band. Therefore, a metamaterial CRLH bandpass filter is designed for the purpose of system miniaturization and smaller insertion loss, and its spurious phenomenon is observed in the frequency domain. And its harmonics in the L-band are suppressed by a compact bandstop filter whose equivalent circuit is newly developed. The design methodology is validated by the equivalent circuit to be compared with commercial full-wave EM software simulations, where the spurious is dropped by 20dB. Also, the advantage of the proposed design is presented by the comparison where our filter is much smaller than the conventional parallel edge coupled filter by over 50%, with excellent harmonic suppression.

• 전자공학회논문지A
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• 제29A권11호
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• pp.49-56
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• 1992

In this paper a band-pass filter using dielectric resonators with tuning screw and spacer at Ku-band is designed and constructed. For the filter design and construction, the coupling coefficient K between two resonators is numberically evaluated. The external quality factor Q$_{ex}$ is also calculated with a microstrip line which is necessary for the field excitation of dielectric resonator. The coupling between dielectric resonator and microstrip line depends mainly upon the magnetic field and is principal parameter in band-pass filter. The Q$_{ex}$ and K data which are evaluated by numberical analysis are practically applied to the filter construction. The theoretical Band-pass filter responses are given by Chebyshev approximation and they are nearly similar to the experimental results.