• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.103-109
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• 2008

In this papaer, a new type of ${\lambda}_g/4$ short stub band pass filter and ${\lambda}_g/2$ open stub band pass filter are purposed. Both are designed using FSCS technique for harmonic suppression. The proposed filters that used FSCS technique and a broadband stop filter is integrated to band pass filter to suppress the harmonics. The BSF are also placed between stubs so that the size is larger than prevent as compared to conventional one. The propose filters have center frequency of 5.8 GHz, bandwidth of 50% and harmonics suppressin is 120% has in bandwith. The measurement results in the case of ${\lambda}_g/4$ short stub filter, insertion loss of 0.5 dB, return loss of 14 dB are achieved and in the case of ${\lambda}_g/2$ open stub filter, loss of 0.8 dB, return loss of 14.4 dB are achieved. The simulation results and the measurement results are almost the same.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1054-1060
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• 2002

In this paper, a new parallel-coupled-line microstrip BPF(BandPass Filter) improving the suppression performance of 2nd harmonic signals is studied. Using the consecutive pattern in coupled-line, the desired passband performance is improved and harmonic passband signal is rejected. Recalculation of classical filter design parameters(space-gap between lines, line widths and lengths) is not required. That is, after using the classical design methodology for parellel-coupled-line BPF, new filters can be easily realized by inserting periodic patterns in coupled-line. To investigate the validity of this novel technique, order-3 Butterworth BPF centered at 2.5 GHz with a 10 % FBW(Fractional Bandwidth) and order-5 Chebyshev BPF centered at 10 GHz with a 15 % FBW were used. When five and three square grooves are used, over 30 dB harmonic suppression at 2nd harmonic is achieved in simulation and experiment.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.227-233
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• 2012

This paper presents a bandpass fitler of GPS and WLAN band based on LTCC. The structure of bandpass fitler consists of a Butterworth lowpass fitler and highpass filter using CRLH (Composite Right/Left-Handed) transmission line. Using green sheet with dielectric constant 7.2, we fabricated the bandpass filter that satisfied GPS and WLAN band characteristics. We are implemented the bandpass filter at center frequency 1.5 GHz (GPS) and 2.4 GHz (WLAN). Its insertion loss are 1.66 dB at GPS and 3.20 dB at WLAN respectively.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.357-360
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• 2003

본 논문에서는 $90^{\circ}$ 하이브리드 결합기에 여파기 특성을 결합하여 전력분배와 하모닉 저지특성효과를 보여주고 있다. 일반적인 $90^{\circ}$ 하이브리드 결합기는 위상차를 갖고 전력을 분배, 합성하는 데에만 쓰이고 있기 때문에 비선형 소자와 결합함으로써 생기는 하모닉 성분을 억제하려면 여파기를 따로 설계해야 하는 단점이 있다. 그래서 본 논문에서는 하이브리드에 저역통과 여파기 특성을 결합함으로써 위상차와 전력분배는 물론 여파기 특성인 감쇠효과를 이용하여 하모닉 성분을 크게 감소시킬 수 있는 구조를 연구하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.3
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• pp.557-564
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• 2000

A microstrip band-pass filter using cross-coupled resonators is designed and studied experimentally. The cross-coupled microstrip hairpin resonator filters exhibit ripples in both passband and stopband. These ripples can improve both frequency selectivity and insertion loss. The cross-coupled filters are not only simple and compact in configuration, but also have great flexibility to form filters into a variety of size. In this paper, a microstrip band-pass filter using cross-coupled resonators is designed at the center frequency of 1.8GHz with bandwidth of 5.0% using Ensemble software. The experimental results show that the bandwidth is about 4.53% at 1.8GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.672-679
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• 1999

This paper describes the design method of active bandpass filters which employ active impedance inverters. Several authors have reported active bandpass filters. However, the functional description of the active blocks in the filters have not been throughly studied. In this paper, the active inverter block of the bandpass filter has is analyzed in the view point of filter design. The designed 3-pole bandwidth filter has its insertion gain of 24 dB at the center frequency of 865 MHz with 75 MHz bandwidth. The noise figure of the active bandpass filter is less than 2.5 dB within its passband.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.457-467
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• 2012

In this paper, a miniaturized band-pass filter structure, which comprises the irises of small resonant aperture and L-type irises inverter, is proposed. Ridged circular aperture iris is chosen as an elementary resonator. L-type iris which is placed between two adjacent elementary resonators is newly proposed as impedance inverter in order to reduce longitudinal length of the proposed filter. The fabricated minimized filter has 400 MHz bandwidth at the 10 GHz center frequency and the whole size is reduced to 70 % in length compared to conventional filter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.3
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• pp.10-17
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• 2003

In this paper, genetic algorithm (GA)-based Thin Film Bulk Acoustic Resonator (FBAR) RF filter design technique is proposed. Since the BVD(Butterworth-Van Dyke) lumped element model is valid only around the resonance, FBAR filter design technique based on BVD circuit has an approximate error. Instead of using BVD model, optimizing filter design method utilizes an analytical electrical impedance equation of FBAR. The geometry of FBAR such as thickness of the piezoelectric layer and area which significantly affect the filter response is optimized by GA. US-PCS Rx Bandpass filter obtained by the proposed technique shows a better response comparing with the typical and BVD-based filter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.7 s.349
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• pp.162-169
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• 2006

A Micorstrip Bandpass Filter Using DBRs for WLAN ($2.3{\sim}2.4GHz$) applications is designed and an EBG structure is employed in the ground plane of the filter to suppress the stopband responses of the filter. The number of DBRs is chosen as two in consideration of low insertion loss and small size of two filter. The center frequency of the filter to be designed is 2.35GHz and its bandwidth is 140MHz. The responses of two kinds of DBR filters (one with EBG and the other without EBG) are calculated and compared with the measurements. The experimental results are in good agreement with the calculations: The bandwidth and insertion loss of the filter with EBG structure are 3.8% and 1.7dB respectively, while those of the filter without EBG structure are 7% and 1.23dB. It is shown that the insertion loss of the filter is increased and its bandwidth is deceased due to the EBG structure. Also the stopband responses of the filters with EBG structures are shown to be much improved compared with those without EBG.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.9
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• pp.1315-1322
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• 1993

본 연구에서는 헤어핀 공진기를 이용하여 L대역 대역통과 MIC여파기를 설계하였다. 여파기의 크기를 줄이기 위해 헤어핀 공진기 간의 결합을 일반결합 대신에 안쪽견합 또는 혼합결합을 사용할 누 있다. 안쪽결합을 사용한 4개의 공진기로 된 여파기는 일반결합 여파기 보다 크기가 20~30% 감소되었다.