• International Journal of Fuzzy Logic and Intelligent Systems
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• 제2권2호
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• pp.115-121
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• 2002

This paper presents an evolutionary design of digital IIR filters using the genetic algorithm (GA) with modified genetic operators and real-valued encoding. Conventional digital IIR filter design methods involve algebraic transformations of the transfer function of an analog low-pass filter (LPF) that satisfies prescribed filter specifications. Other types of frequency-selective digital fillers as high-pass (HPF), band-pass (BPF), and band-stop (BSF) filters are obtained by appropriate transformations of a prototype low-pass filter. In the GA-based digital IIR filter design scheme, filter coefficients are represented as a set of real-valued genes in a chromosome. Each chromosome represents the structure and weights of an individual filter. GA directly finds the coefficients of the desired filter transfer function through genetic search fur given filter specifications of minimum filter order. Crossover and mutation operators are selected to ensure the stability of resulting IIR filters. Other types of filters can be found independently from the filter specifications, not from algebraic transformations.

• 대한전자공학회논문지TC
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• 제45권6호
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• pp.8-12
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• 2008

본 논문에서는 링 공진특성을 이용하여 사이드밴드 억압비가 향상된 링 공진기형 필터를 제안하고 구현하였다. 이 링 공진 특성은 직선 전송선로와 링 전송선로의 일부 결합효과로 인하여 발생되며, 이 결합효과는 신호의 전달특성에 중요한 영향을 미친다. 또한, 링의 반지름을 조절하여 가변적으로 채널 선택이 가능하다. 본 논문에서는 기존의 링 여파기 하단에 링 전송선로를 추가함으로써 대역통과 특성이 조절되는 링 공진 여파기를 구현할 수 있었다. 필터 소자측정 결과, 중심주파수가 약 4 GHz에서 추가 삽입손실 없이 대역폭을 조절할 수 있었다. 출력된 대역통과 특성의 양쪽 사이드밴드에 나타난 미세한 잡음을 추가된 링을 통해 제거시킴으로써, 신호의 진폭억압비를 향상시킬 수 있었고, 필터 시스템의 성능을 결정하는 Qe는 82였으며, 기존 필터보다 105% 향상시킬 수 있었다.

• 전자공학회논문지D
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• 제35D권8호
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• pp.82-88
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• 1998

We propose and design a new type of anrrow band-pass optical filter based on two fiber gratings with different reflection wavelength. The ripples occur in the spectra of the filter with two uniform fiber gratings. Our simulation results also show that the ripples disappear with the fiber gratings apodized to both gaussian and hyperbolic tangent function. The hyperbolic tangent function seems to be a better apodization function for improving the filter's performance in terms of narrow pass bandwidth and high transmission.

• 한국ITS학회 논문지
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• 제12권6호
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• pp.37-43
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• 2013

본 논문에서는 SIR(Stepped Impedance Resonator) 구조를 이용한 초광대역(UWB:Ultra Wide Band) 개방형 스터브 대역통과 여파기를 제안한다. 제안한 개방형 스터브 대역통과 여파기는 초광대역을 구현하기 위해 스터브 위치에 SIR 구조를 적용하였으며 낮은 삽입손실을 갖는다. 제안된 대역통과 여파기의 대역폭은 중심 주파수 5.8GHz에서 103% 이고, 삽입 및 반사손실은 각각 0.17dB 및 13.1dB이며 전체의 크기는$21.6{\times}17.8mm^2$ 이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.31-34
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• 1998

CDMA base station SAW filter has been designed and fabricated successfully. Through the computer simulation, SAW filter is designed to have center frequency of 69.99MHz, ripples lower than 0.7dB and rejection level lower than 50dB. To obtain low noise band pass SAW filter, Input electrode has a apodization type and output electrode has a withdrawal type. For the fabrication of the SAW filter, Al thin film is deposited to the quartz substrates. The fabricated SAW filter has center frequency of 70.5MHz, ripples of 1dB and rejection level of 45dB.

• 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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.163-166
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• 2005

Multilayer LTCC technology enables RF modules to be reduced dramatically by taking advantage of the three dimension flexibility. Compared to a conventional two dimensional PCB, LTCC allows higher density, reduced size, and lower cost. In this research, BPF based on LTCC for 900MHz ZigBee application was implemented which can replace SAW filter with using the material of the Dupont9599's dielectric constant 7.8. And distributed baud pass filter for 900MHz ZigBee system applications is presented. Using resonator stripline and capacitance, 2nd order band pass filter was designed. Adjusting resonator's length and capacitance is easy to tune at accurate center frequency by shifting band because ZigBee system is using narrow bandwidth, $902MHz^{\sim}928MHz$. Also resonator has no limitation in space, so reducing size is possibile. Designed filter had I.L. 2.8dB at 915MHz and attenuation at 815MHz, 1015MHz was 16dB, 15dB, respectively. Therefore, the sharpe cut-off and good insertion loss for ZigBee system application.

• ETRI Journal
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• 제27권5호
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• pp.643-646
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• 2005

This letter proposes a band-pass filter (BPF) with two transmission zeros based on a combination of parallel coupling and end coupling of half-wave transmission lines. The fabricated BPF exhibited a narrow bandwidth and two transmission zeros near the pass-band due to the end-coupled and shielding waveguide. At the center operation frequency of 60 GHz, the 20 dB bandwidth of the BPF is 1.0 GHz, which is almost 2% of the center operation frequency, and the insertion loss is 3.12 dB. Two transmission zeros reach approximately 40 dB at 58.5 and 62.5 GHz. The simulation results almost agree with the measured results.

• 전자공학회논문지B
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• 제32B권7호
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• pp.1036-1044
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• 1995

In this paper, a band-pass filter is implemented with the diffusion and difference processes by using the diffusion neural network model. The center frequency of this band-pass filter can be varied by iterations of the diffusion and difference operations, and the selectivity can be determined by iterations of the difference operation. We propose an efficient algorithm that can generate various band-pass filters using arbitrary diffusion and difference iterations. This algorithm needs only simple operations of diffusion and difference.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.215-218
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• 2009

In this paper, Dual-band bandpass filter studied design using Parallel Coupled SIR(Stepped Impedance Resonator). This Dual-band bandpass filter design SIR of half-wavelength by Parallel-coupled type that is available to RFID system and Changed structure in Meander form by size reduce. Because seen Dual-band bandpass filter is designed so that is applicable for frequency 433MHz and 2.45GHz of RFID system is very wide distance between two pass-band, establish 433MHz by fundamental frequency and controlled 2.45GHz by 2st spurious resonance frequency bandstop filter of 1st spurious resonance frequency and Parallel coupled SIR Combine to remove 1st spurious resonance frequency.