• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.5
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• pp.97-102
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• 2012

In this paper, each electrical length and harmonics of the multi-stage SIR are calculated by using the input impedance for the variable application of SIR in the microwave systems. The size reduced ratio of the SIR is slightly reduced as increasing of the number of stage. The impedance ratio between lower and higher impedance of the SIR has the dominant effect on the size reduced ratio and harmonic characteristics. Also the equivalent impedance of the SIR is a geometric mean between lower and higher impedance and the quality factor of the SIR is similar to the half-wavelength resonator's.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.463-470
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• 2015

In this paper, a new dual-band bandpass filter(BPF) that has resonators and feed lines with Stepped-Impedance Resonator(SIR) structures is proposed. Feed lines with SIR structure provide maximum magnetic field points which occur at the same locations of the input and output feed lines, so the insertion loss of BPF was reduced. Applying the SIR structure to the BPF for the first passband improves rejection characteristics between the first passband and the second passband. It reduces the coupling between the BPF for the first passband and the BPF for the second passband, so it makes the dual-band BPF more compact. The proposed design method provides independent changes of both the center frequency and the bandwidth for each resonator, and also improves filtering characteristics. The validity of the proposed design method is confirmed by comparisons between the designed parameters and the measured results satisfying WLAN specifications.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.2
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• pp.78-85
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• 1998

The design method of a temperature stable bandpass filter using dielectric coaxial resonators of with two dielectric ceramics with opposite signs of temperature coefficient of dielectric constant (${\tau}_{\epsilon}$) to compensate for each other in this method. $MgTiO_3$(${\tau}_{\epsilon}$=+99 ppm/${\circ}C$) as a positive ${\tau}_{\epsilon}$ material and Ba($Zn_{1/3}Nb_{2/3}$)$O_3$(${\tau}_{\epsilon}$=-77ppm/${\circ}C$) as a negative material were selected. The length of a SIR for the temperature stability was calculated according to the design method and the susceptance slope parameter of the SIR was obtained. A temperature stable bandpass filter using dielectric SIR's was designed, simulated and fabricated. The center frequency of this filter was 915 MHz and the pass bandwidth was 20 MHz. Temperature properties of this bandpass filter by simulations were compared with the measured results of the bandpass filter fabricated.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.326-332
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• 1999

In this paper, we designed and fabricated High-Tc Superconducting (HTS) microstrip bandpass filters using Stepped Impedance Resonators(SIR) and studied on their characteristics. The $high-T_c$ superconducting $Y_1Ba_2Cu_3O_{7-x}$ epitaxial films were deposited by Pulse Laser Deposition (PLD) system on MgO. The fabricated filters were designed so as to operate in Ku band with central frequency 17.25 GHz, bandwidth 2.896% and ripple 0.01 dB. These filters were composed of parallel coupled microstrip SIR of which impedance ratio (K) are 0.5, 1.5. In the measured response, HTS filters had showed insertion loss below -0.5 dB. For comparison with normal conducting filter, we fabricated the Au counterpart that consists of the resonators as K=1.5 in the same dimension and measured performance of the Au filter. In comparison, HTS filter designed optimally got superior response to gold conterpart.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.387-390
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• 1998

We propose comb-line filter using SIR(Stepped Impedance Resonator) with two transmission line. The coupling structure of the filter is double coupled line where two coupled lines are linked with cascade. We find out the inverter function of the filter. using even and odd mode impedance. The merits of the filter are that first, we can design transmission zero point at any frequency that we wanted without using lumped elements : chip capacitors and inductors. Second, we can design small size filters. To validate the inverter function of the filter with double coupled line we designed and fabricated two-pole band pass filter with the proposed filter structure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.447-452
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• 2011

In this paper, we present a compact triple-mode resonator. The resonator itself can provide three transmission poles and one transmission zero. The resonance condition of each mode is analyzed theoretically, and the transmission zero is generated by open stub. Using this proposed resonator, a compact three pole bandpass filter for 2.4 GHz WLAN application with one transmission zero is designed and fabricated. The fabricated triple-mode filter shows 3 dB bandwidth of 15.8 % with the center frequency 2.4 GHz and less then 1.17 dB in 2.4~2.5 GHz passband. The size of fabricated triple-mode filter including the feed lines is 15.9 mm${\times}$9.7 mm and very compact compared with previous reported triple-mode filter.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.1
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• pp.138-143
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• 2009

In this paper, a novel ultra-wide band filter which is operating at frequency bands from 3.1 GHz to 10.6 GHz is suggested. It is modified from the conventional ring filter and consisted of a ring with two parallel open-stub with length of ${\lambda}/8$. It improves the sharpness of the conventional ring filter and is compact. The measured results show that the fabricated filter has a insertion loss of 2.1 dB and the measured group delay of the filter is less than 463 ps through UWB frequency bands.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1603_1604
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• 2009

본 논문에서는 SIR(Stepped Impedance Resonator)를 이용하여 RFID 주파수 대역의 이중대역 필터를 설계 연구하였다. 반파장 SIR을 parallel-coupled 형태로 설계하고 넓은 주파수 간격의 이중대역필터를 구현하기 위해서 2st 공진 주파수를 2.45GHz 대역에 맞추고 1st 공진 주파수를 억제하기 위해서 대역저지 필터를 결합하였다. 입출력에 대역 저지 필터를 구성하고 반파장 parallel-coulpled SIR은 미앤더 구조로 설계하여 크기를 줄였다. 본 논문에서 설계된 필터는 두 대역에서 -3.5~3.9dB의 삽입 손실을 가지며 433MHz에서 8MHz, 2.45GHz에서 21MHz의 대역폭을 나타낸다. 관심 주파수 이외의 대역에서는 -50dB 이상의 저지 특성을 가진다.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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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.

• ETRI Journal
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• v.31 no.4
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• pp.475-477
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• 2009

A balanced dual-band bandpass filter based on ${\lambda}$/2 stepped-impedance resonators and open-loop resonators is proposed in this letter. By employing a type of self-feedback structure, an extra transmission zero is introduced near the common-mode resonance frequency, and the common-mode signal is suppressed. The measured results indicate that the filter can operate in 2.46 GHz and 5.6 GHz bands, and the insertion loss is 1.85 dB and 1.9 dB, respectively. Also, better common-mode suppression is achieved.