• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.267-276
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• 1999

A 2 stage 6-pole bandpass filter (BPF) is designed and implemented by using K-band triple-mode cavity. The BPF has an 100MHz bandwidth at the center frequency of 18.5GHz and the response of the filter is Chebyshev function. The cavity filter uses two orthogonal $TE_{113}$ modes and one $TM_{012}$ mode. To obtain a Chebyshev response, the intercavity coupling between the adjacent cavities is accomplished by H-field component of TE modes parallel to slot plate. In this paper, the size and location of intercavity slot are determined by the detailed coupling equation from H-field of TE resonant modes in circular cavity. The measured results agree well with the theoretical one.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.753-759
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• 2020

A modified Chebyshev lowpass filter function with progressively diminishing ripples in the passband is proposed and analyzed in the frequency domain. Owing to the diminishing ripples, the passband magnitude characteristic of the proposed Chebyshev function has improved compared to the classical Chebyshev function. In addition, the phase characteristics of the proposed Chebyshev function were improved considerably compared to that of the Chebyshev function, and the time delay of the proposed function was much simpler and flatter. In addition, the proposed Chebyshev filter was realizable by the passive doubly terminated ladder network delivering maximum power transfer for the order n, even or odd, thus making themselves amenable to low-sensitivity active RC or switched capacitor filters through the simulation techniques. To verify the proposed Chebyshev filter characteristics, a 6th order passive doubly terminated ladder lowpass filter was designed and analyzed using the MATLAB and SPICE program. Thus, the proposed Chebyshev function can remove the drawbacks of the classical Chebyshev function and could be applicable to the design of a filter with an improved filter size, phase, and time delay characteristics for various signal processing.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1527-1529
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• 2002

본 논문은 저손실 소형 대역통과 여파기인 기지국용 RF/Microwave 수동소자의 다중 공진 모드(Multi-Mode)에 관한 연구로 한개의 유전체 공진기(Dielectric Resonator)로 두개의 공진 모드(Dual-Mode)를 형성하고 그의 결합량을 조절하여 대역통과 여파기를 설계 및 제작하고, 기지국용 Dual-Mode 대역통과 여파기의 소형화, 경량화를 50%이상 향상시켜 양질의 Dual-Mode 공진 특성을 관찰하였다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3139-3141
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• 2000

전압제어 트랜스컨덕터를 설계하여 튜닝범 위가 넓은 Gm-C 대역통과 필터를 CMOS 공정으로 설계하였다 Gm-C 필터는 트랜스컨덕터와 캐패시터로 구성된 적분기를 기본으로 구현되고 있다. 따라서 트랜스 컨덕터는 출력단에 캐패시터를 연결하였을 때 이상적인적인 적분기의 특성에 가까울수록 필터의 특성이 좋아지고 PLL 구조의 튜닝이 용이해진다. 본 논문에서는 1:3이상의 범위에서 튜닝이 가능하고 PLL을 기본으로한 자동튜닝과 선형전압 튜닝을 조합하여 주파수 제어회로를 설계하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1313-1321
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• 2000

This paper presents a novel HTS microstrip pseudo-lumped element resonator for the compact and simple filter design. A 7-pole bandpass filter with quasi-elliptic response is designed and fabricated using non-adjacent couplings between resonators. A seven-pole quasi-elliptic filter is fabricated using double sided YBCO on a LaAlO$_3$ substrate with thickness of 0.5 mm and dielectric constant of 23.5. The filter has an insertion loss of 0.8 dB at 20K, a bandwidth of 8 MHz at the center frequency of 1774 MHz, and an attenuation of 33 dB for the cut-off-band of 1 MHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.201-206
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• 2015

A new electronically stopband tunable filter is proposed with three-input single-output using Operational Transconductance Amplifier (OTA) in this paper. The proposed filter provides band pass, low pass and high pass multifunctional responses. Centre frequency ($f_c$) and quality factor (Q) of the realized filters could independently tuned without disturbing each other. Various network sensitivity and non-ideal characteristic analysis are done to check the sensitivity and parasitic effect of different circuit parameters. The CMOS realization of filter is done with 1.8V-0.18um process parameters and HSPICE simulation results are presented to assert the presented theory.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.98-103
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• 2001

The binaural auditory system of human has the capability of differentiating the direction and distance of sound sources. This feature is well characterised in terms of the inter-aural intensity difference (IID), the inter-aural time difference (ITD) and/or the spectral shape difference (SSD) arising from the acoustic transfer of a sound source to the outer ears. This paper proposes an effective way of extracting the three sound perception factors (IID, ITD, SSD) from the head-related transfer functions (HRTF's) that depends on the direction and distance of the acoustic source from the listener. It includes the estimation method of the equivalent ITD and 1/3-octave band-based IID factors and their usage to locate a sound source in space. Subjective and objective tests were carried out to examine the effectiveness of the proposed methodology and its applicability to real sound systems. Those experimental results are illustrated in this paper.

• Journal of IKEEE
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• v.12 no.4
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• pp.225-233
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• 2008

This paper presents a compact, low insertion loss, sharp rejection and wide band microstrip band pass filter that is composed rectangular loop resonator and step-impedance-open-stub(SIOS) for wireless data communication. The SIOS can be reduce length about 30% more than general 0.25${\lambda}$ stub. And stubs can have the advantage of tuning impedance magnitude. In order to demonstrate agrement of this paper prove, the optimized wide band pass filters are realized and experimented. A transmission line model used to calculate the frequency response of the new filters shows good agreement with measurements. The filter with perturbation stubs has four poles at rejection band, the poles are excited 3.610GHz, 4.265GHz at low frequency band, 8.494GHz, 9.056GHz at high frequency band. And the filter has 3dB fractional bandwidth of 57%(3.695GHz), an insertion loss of better than 0.37dB from 4.549GHz to 8.244GHz, and two rejection of greater than 30dB within 237MHz(4.312GHz${\sim}$ 4.549GHz) at low frequency band, 234MHz(8.244GHz-8.491GHz) at high frequency band.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.483-488
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• 2020

In recent years, the demand for wireless devices incorporating several wireless communication systems into one has been increasing in order to provide services that meet the diverse needs of consumers. Wireless devices consisting of various wireless communication systems require many frequency fixed filters. A frequency tunable filter can replace a number of frequency fixed filters in the wireless devices. If a frequency tunable filter is used in wireless systems, the system can be configured more efficiently. In this paper, a 3-pole frequency tunable BPF(bandpass filter) operating in the frequency band of 800 ~ 2400MHz is designed. In order to widen the operating frequency band, a tuning screw is designed to have a step and a linear motor is used to facilitate the adjustment of the tuning screw. The implemented frequency tunable BPF operates in the designed frequency range and has the maximum insertion loss of 2.82dB in the channel band and the minimum attenuation of 18.7dB at ± 50MHz frequency offset from the center frequency of the band.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.43-52
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• 1999

We propose a new method for tuning of center wavelength in photorefractive filter using $LiNbO_3$ crystal doped with 0.015Wt.% Fe. through the filter bandwidth property analysis using the geometrical method, a new wavelength selectivity theory was presented. In this scheme, the tuning of the center wavelength can be achieved by the real time incident angle control of the received heam, which was gotten by the spatial light modulator. So, tuning time depend on the response time of the SLM and results in the high speed turing. Because the use of thermally fixed grating in our filter, it has uniform diffraction property to the all filtering wavelength. Designed tunable filter has 4nm bandwidth and composed of the three channel with 10nm space. From the optical experiment, we get the 4.5nm, 4.25nm, 4nm bandwidth and 1530.5nm, 1540.5nm, 1549.5nm center wavelength respectively.