• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1758-1763
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• 2013

This paper is a study on the performance of the stable cascading BPF. There are generally two methods of designing IIR filter, which are a direct method and an indirect one. The indirect design method that is transformed into the BPF by frequency transformation using the prototype analog LPF which is satisfied for designing specifications is applied to this study. As typical prototype analog LPFs, there are the Butterworth filter, the Chebyshev filter and the elliptic filter. In this study, we connect the frequency transformed BPFs (to the cascade form) which have been converted from the stable Butterworth filter and Chebyshev filter. Three classified simulations are conducted in this study, which are the cascading Butterworth BPF Only, the cascading Chebyshev BPF Only and the cascading Butterworth and Chebyshev BPFs. As a result of the simulation, this study shows that a ripple size of the cascading Chebyshev BPF Only is about 1[dB] smaller than that of the cascading Butterworth and Chebyshev BPFs and also the skirt characteristic of the cascading Chebyshev BPF in the transition band is most outstanding and has the widest bandwidth. The result of performance comparison shows the validity of specifications required in the workplace.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.598-604
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• 2015

A Chebyshev filter is well known for having a sharp skirt characteristic and equi-ripple. On the other hand, a Butterworth filter has a smooth skirt characteristic and maximally flat ripple. This paper analyzes the skirt characteristics of the filters with the cascade connection. The paper deals with the Chebyshev BPF, Cascading Chebyshev BPF, Butterworth BPF, Cascading Butterworth*Chebyshev BPF. First of all, the paper designs the prototype analog LPF in order to analyze skirt characteristics of the BPFs. Then the paper does the frequency transformation into the BPFs and tests the BPFs with cascading them. As a result, the skirt characteristics of the Chebyshev BPF was the sharpest and those of the Cascading Chebyshev BPF, Butterworth BPF, Cascading Butterworth*Chebyshev BPF was superior in order. The validity of the paper was confirmed through minute measurements of test results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.438-446
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• 2005

In this paper, the modified generalized Chebyshev rational function is presented. The new element values of prototype low pass filter are obtained by network synthesis using this rational function. This proposed filter has an equal ripple passband as same as conventional generalized Chebyshev filter, but unlike conventional filter which has only one attenuation pole at finite frequency, the proposed filter has two different from each other attenuation pole in stopband. If the harmonic frequency is set to the second attenuation pole frequency, this harmonic is suppressed efficiently. Furthermore, since the location of the second attenuation pole can be arbitrary adjusted. our filters are very available for the realization of wide stopband, particularly.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.13-16
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• 2005

Many mobile communication systems require bandpass filter with sharp skirt characteristics and consequently a filter was formed by more order. It needs to improve flatness in passband. In this paper, amplitude equalizer was used to improve the flatness of passband. We modified Chebyshev prototype filter by use of network synthesis and computed the prototype elements for Shaping filter. We designed and realized a 13-order combline bandpass filter and 4-order amplitude equalizer with coaxial dielectric resonators at WiBro band. The measured results show $\pm$0.82 dB amplitude difference in passband, 6 dB improved flatness.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.338-342
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• 2003

본 논문에서는 개방 스터브(open stub)와 전송선로가 커플된(coupled) 구조를 Chebyshev prototype을 이용하여 저역통과 여파기를 설계하였다. 같은 길이의 스터브를 연속적으로 배열함으로써 깊은 저지대역을 갖고, 커플링에 의해 우수한 스컷 (skirt) 특성을 갖는 여파기를 설계할 수 있었다. 또한, 감쇄극이 다른 스터브를 추가로 연결하여 저지대역을 확장하였다.

• Journal of electromagnetic engineering and science
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• v.19 no.1
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• pp.64-70
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• 2019

In this study, a compact series-fed center-fed open-stub (SFCFOS) linear array antenna for K-band applications is presented. The antenna is composed of a single-line 10-element linear array. A symmetrical Chebyshev amplitude distribution (CAD) is used to obtain a low sidelobe characteristic against a uniform amplitude distribution (UAD). The amplitude is controlled by varying the width of the microstrip patch elements, and open-ended stubs are arranged next to the last antenna element to use the energy of the radiating signal more effectively. We insert a series-fed stub between two patches and obtain a low mutual coupling for a 4.28-mm center-to-center spacing ($0.7{\lambda}$ at 21 GHz). A prototype of the antenna is fabricated and tested. The overall size of the uniform linear array is $7.04{\times}1.05{\times}0.0563{\lambda}_g^3$ and that of the Chebyshev linear array is $9.92{\times}1.48{\times}0.0793{\lambda}_g^3$. The UAD array yields a ${\mid}S_{11}{\mid}$ < -10 dB bandwidth of 1.33% (20.912-21.192 GHz) and 1.45% (20.89-21.196 GHz) for the CAD. The uniform array design gives a -23 dB return loss, and the Chebyshev array achieves a -30.68 dB return loss at the center frequency with gains of 15.3 dBi and 17 dBi, respectively. The simulated and measured results are in good agreement.

• The Journal of the Acoustical Society of Korea
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• v.28 no.6
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• pp.491-498
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• 2009

This paper presents the design method of an impedance matching network using an isolation transformer and the Chebyshev filter function for the high efficiency and the flat power driving of an underwater acoustic piezoelectric transducer. The proposed impedance matching network is designed for minimizing the reactance component of transducer and having the flat power response in the wide frequency range. We design a low pass filter with ladder-type circuit using the Chebyshev function as standard prototype filter function. In addition, we design the impedance matching network which is suitable for the equivalent circuit of transducer and the turn ratio of transformer through the bandpass frequency transformation. The proposed method is applied to the simulated dummy load of the tonpilz-type transducer operating in the middle frequency range. The simulation results are compared with the measured characteristics and the validity of the proposed method is verified.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.95-100
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• 2006

In this paper, we designed amplitude equalizer which is composed of amplifier, complementary shaping filter and attenuator in order to improve flatness of high order bandpass filter. We modified Chebyshev polynomial and calculated the prototype elements for complementary shaping filters by network synthesis. The amplitude equalizer is realized that it connects the 4th order complementary shaping filter designed by using calculated the prototype elements to the amplifier compensating for insertion loss and improving return loss, and with the attenuator for gain control. Using proposed amplitude equalizer, We certificated improvement in flatness of 13th order bandpass filter at WiBro band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.154-160
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• 2005

Microwave Otters are essential device in modem wireless systems. A compact dimension BPF(Band-pass Filter) for IEEE 802.11a WLAN service is realized using LTCC multi-layer process. To extrude 2-stage band-pass equivalent circuit, band-pass and J-inverter transform applied to Chebyshev low-pass prototype filter. Because parallel L-C resonator is complicate and hard to control the inductor characteristics in high frequency, the shorted $\lambda/4$ stripline is selected for the resonator structure. The passive element is located in the different layers connected by conventional via structure and isolated by inner GND. The dimension of fabricated stacked band-pass filter which is composed of six layers, is $2.51\times2.27\times1.02\;mm^3$. The measured filter characteristics show the insertion loss of -2.25 dB, half-power bandwidth of 220 MHz, attenuation at 5.7 GHz of -32.25 dB and group delay of 0.9 ns at 5.25 GHz.