• ETRI Journal
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• 제26권4호
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• pp.292-296
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• 2004

In this paper we present a new current-mode electronically tunable universal filter using only plus-type current controlled conveyors (CCCII+s) and grounded capacitors. The proposed circuit can simultaneously realize lowpass, bandpass, and highpass filter functions - all at high impedance outputs. The realization of a notch response does not require additional active elements. The circuit enjoys an independent current control of parameters $\omega_0$ and $\omega_0/Q$. No element matching conditions are imposed. Both its active and passive sensitivities are low.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.99.2-99
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• 2001

An electronically tunable current-mode second-order multifunctional filter is described in this paper. The proposed filter consists of two four-terminal floating nullors (FTFNs), two dual-output OTAs and two grounded capacitors. The circuit can simultaneously realize the lowpass, bandpass and highpass current transfer functions from the same configuration without changing the circuit configuration and elements. The natural angular frequency we and the parameter wo/Q can be orthogonally controlled through adjusting the transconductance gain of OTA. PSPICE simulation results are employed to confirm the circuit performance.

• 한국전자파학회논문지
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• 제18권5호
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• pp.522-529
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• 2007

마이크로파 광대역 능동 주파수 분주기는 가변 위상 변환기(tunable polyphase filter)와 가변 영상 주파수 제거 혼합기(tunable image-rejection mixer)를 연결한 것에 정적 이분 주기(static divide-by-2)를 궤환 경로로 연결하여 구성하였다. 출력에서 원하지 않는 불요파 신호를 영상주파수 제거 혼합기와 가변 위상 변환기를 조정함으로써 넓은 주파수 영역에서 제거할 수 있었다. GaInP/GaAs HBT 공정을 이용하여 설계된 1.5 분주비를 갖는 주파수 분주 회로는 4.5 GHz에서 9.2 GHz의 광대역 입력 주파수 영역에서 동작하였으며, $1/3{\times}f_{in}$과 $f_{in}$ 불요파 성분이 모두 -20 dBc 이하로 억제되었다. 소모 전력은 4.1 V에서 29 mA이다.

• 한국산학기술학회논문지
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• 제11권10호
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• pp.3905-3910
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• 2010

본 논문에서는 3차 체비세프 전류모드 필터가 1.8V-$0.18{\mu}m$ CMOS 파라메터로써 설계되었다. 전류모드 필터의 기본 회로는 제안된 전압제어 주파수 가변 전류모드 적분기로 구성되었다. 제안된 전류모드 적분기를 사용함으로써 필터의 차단주파수가 가변될 수 있으며 또한 전체 소비전력을 줄 일 수 있다. HSPICE 시뮬레이션 결과, 필터의 차단주파수는 1.2MHz에서 10.1MHz로 조절되었고 전체 소비전력은 1.8V 공급전압에서 2.85mW으로 확인되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.581-584
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• 2002

In this work, a CPW resonator was designed and fabricated to investigate the basic microwave properties, such as effective dielectric constant, of BST thin films. Their properties were used as basic data to simulate and design CPW tunable bandpass filter. We also report on gold/$Ba_{0.5}Sr_{0.5}TiO_3$(BST) ferroelectric thin film C-band tunable bandpass filters(BPFs) designed and fabricated on magnesium oxide substrates using CPW structure. The 2 pole filter was designed for a center frequency of 5.88 GHz with a bandwidth of 9 %. The BST based CPW filter offers a high sensitivity parameter as well as a low loss parameter. The tuning range for the bandpass filter with CPW structure was determined to be 170 MHz.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권11호
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• pp.627-634
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• 2000

In this paper, new micromachined tunble bandpass filters for multi-band millimeter-wave telecommunication systems are proposed. Two types of mm-wave tunable filters are fabricated using micromachning technology and the responses of the filters are measured. One is two-pole lumped elements filter and the other two-pole resonators filter. Frequency tunability of the filter is achieved by changing the gap between a common CPW ground plate and the movable cantilever beam connected to the transmission line with the controllable renge of 2.5${\mu}m$. The deflection of cantilever beam is measured with the applied DC voltage. With the applied bias voltage from 0 to 50 V, the fabricated filters show 0.6 GHz(2.3%) at 26.6 GHz, and 0.8 GHz(2.5%) at 32 GHz center frequency shift for the lumped elements and resonators filter, respectively. The life time of the fabricated gold cantilever structure are tested.

• 전기학회논문지
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• 제60권4호
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• pp.871-876
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• 2011

In this paper, a voltage-controlled frequency tunable current-mode integrator and a 3rd-order current-mode Chebyshev filter in 1.8V-$0.18{\mu}m$ CMOS is realized for software radio applications in system-on-chips. This filter is used for reconstruction purposes between a current-steering DAC and a current-mode mixer. Power consumption of the designed filter can be reduced by using a current-mode small size integrator. And also, cutoff frequency of this filter is variable between 1.2MHz and 10.1MHz, the power consumption is 2.85mW. And the voltage bias compensated circuit is used to control the voltage variation.in the designed filter.

• 전자공학회논문지D
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• 제35D권1호
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• pp.16-26
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• 1998

This paper presents a design methodology for magnetically tunable X-band E-plane type waveguide filters. The proposed design is based on using of quarter wavelength transmission line for compensating the negative length transmission line of end K-inverters of E-plane type waveguide filters. The derived formulae are applied for initial design and the correction method is also provided for final design by considering the frequency dependent characteristic of K-inverters. The analysis results of E-plane pype waveguide structure loaded with ferrite slab are obtained using the edge based finite element method including higher order mode effecets. It is shown that the unilateral finline E-plane type waveguide filter as well as the bilateral finline E-plane type waveguide filter achieves the the manetically tunable characteristic. The X-band experimantal results for bilateral and unilateral finline E-plane type waveguide filters agree well with the simulated data.

• 전기학회논문지
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• 제56권6호
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• pp.1117-1121
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• 2007

We demonstrate a wavelength swept mode-locked ring laser for the frequency domain optical coherence tomography(FD OCT). A laser is constructed by using a semiconductor optical amplifier, fiber Fabry-Perot tunable filter and 2.6 km fiber ring cavity. Mode-locking is implemented by 2.6 km fiber ring cavity for matching the fundamental or harmonic of cavity roundtrip time to a sweep period. The wavelength sweeps are repetitively generated with the repetition period of 77.2 kHz which is the parallel resonance frequency of Fabry-Perot tunable filter for the low driving current consumption of the fiber Fabry-Perot tunable filter. The wavelength tuning range of the laser is more than FWHM of 61 nm centered at the wavelength of 1320 nm and the linewidth of the source is $0.014{\pm}0.002$ nm.

• 분석과학
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• 제8권4호
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• pp.1101-1108
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• 1995

Acousto-optic tunable filter is a compact, all solid state electronic dispersive device. It is based on the acousto-optic interaction in an anisotropic crystal. Compared to conventional grating monochromators. the AOTF has no moving parts, wider spectral tuning range (from UV through visible and near-IR to IR), higher throughput, higher resolution, faster scanning (${\mu}s$) and random wavelength access. These features make it possible to use the filter to develop novel instruments which are not possible otherwise. The instrument development and unique advantages of such AOTF based instruments including the multidimensional fluorimeter, the multiwavelength thermal lens spectrometer, and the detectors for HPLC and flow injection analysis are described.