• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.29-34
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• 1989

The analysis and design procedure for 5-coupled microstrip line structure for applications as a wide bandpass/bandstop filter for MIC and MMIC are presented to implement this one. The measured frequency responses for the transmission coefficient are in good agreement with the theoretical results predicted.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.834-838
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• 2007

A coupled-defected ground structure(C-DGS) having closely-located DGS cells is proposed for high performance bandstop filter applications. The negative coupling of ground currents between adjacent DGS cells greatly improves the stopband characteristics. We have measured the attenuation slope of 110.8 dB/GHz and -20 dB rejection band from 3.8 GHz to 15.5 GHz. Compared to the double-plane BSF, the proposed BSF improved the sharp cutoff response 7.6 times. We expect the C-DGS be helpful to improve the performance of DGS application circuits and also to extend the possible DGS applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.85-89
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• 2017

This paper proposes an antenna incorporating a bandstop filter to miniaturize the rectenna used for wireless power transmission with the emerging interest these days. To suppress the harmonics that can be re-radiated, this paper proposes a microstrip patch antenna that can suppress the harmonics while maintaining the size of the antenna by inserting a U-slot, which acts as a bandstop filter, on the ground plane of the antenna. As a result, S11 of the second harmonic(4.6GHz) was reduced from -5.61dB to -0.338dB and the efficiency was suppressed significantly from 29.76% to 1.5%. In addition, the maximum gain was reduced to -12dBi from 2.89dBi. On the other hand, at the fundamental frequency (2.45GHz), the S11 value was reduced from -18 dB to -15 dB, and the efficiency was reduced slightly from 68.2% to 60%. In the case of applying a microstrip antenna combined with the proposed bandstop filter to a rectenna, it is believed that the harmonics that degrade the performance of the rectenna can be removed effectively while reducing the large area occupied by harmonic suppression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.1-5
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• 2017

In this paper, we propose a wideband band-stop filter (BSF) in order to extend the stopband of the band-stop filter using a symmetric dual spurline and the coupled open stub. First, we know that the symmetric dual spurline structure is advantageous in widening the stopband, as compared to the asymmetric dual spurline structure. So we designed a band-stop filter that combines the electrically coupled open stub (ECOS) band-stop filter with a symmetric dual spurline. We can greatly extend the stopband, when it is combined with the dual spurline and electrically coupled open stub on a microstrip transmission line, without any size increment. The stopband of the proposed band-stop filter is extended by approximately 244% (rejection depth: -20 dB) compared with a band-stop filter without a dual spurline.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.1
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• pp.52-62
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• 2003

In this paper, photonic bandgap(PBG) bandstop filters which are composed of periodically etched circles in the ground plane show good microwave characteristics with the harmonic suppression on stopband. The PBG structures were analyzed using a finite-difference time-domain(FDTD) simulation and experimental measurement. The FDTD technique is used because it can simulate arbitrary 3-D structures and provide broadband frequency response. The analysis results are presented it is the same that only one row of etched circles and 2-dimension three rows of etched circles. And we show the PBG resonator characteristics between etched circles using field pattern and frequency characteristics as functions of etched circle number n, etched circle radius r and period a.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.11
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• pp.34-39
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• 2002

In this paper, we proposed novel photonic bandgap(PBG) structure using EGP(Elevated Ground Plane) and via in ceramic substrate of microstrip line. From analysis result, the proposed PBG structure is reduced 52.5% at size and increased 45 % at bandwidth compared to typical planar PBG structure. It is also reduced 32 % at size and improved more than 8 dB at power loss compared to typical multilayer DGS(Defected Ground Structure). The proposed PBG structure also can be used bandstop and lowpass filter and it will be useful for small microwave integrated circuit and module development.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1423-1431
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• 2010

In this paper, the dual-band compact broad bandpass filter using parallel coupled line is proposed. The proposed filter has reduced size and can be controlled bandwidth. And it is also possible to operate in the dual-band purpose. Futhermore, the inserted bandstop fiilter with T-type configuration is also possible to operate in the same purpose. The dual-band bandpass filter has the first operating frequencies and its bandwidth which are 5.8 GHz and 60 % respectively and the second operating frequency and the bandwidth are 16.2 GHz and 60 % respectively. The insertion loss and the return loss of the first frequency has 0.4 dB and 17.4 dB and the insertion loss and the return loss of the second frequency has 0.62 dB and 19.8 dB, respectively.

• 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.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.26-31
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• 2015

This paper deals with a size-reduced Ku-band waveguide limiter. Basically, it passes the signal from 16.125 GHz through 16.375 GHz, but when excessively high power is injected to the input port, it should change to a bandstop filter. Furthermore, it is required to change to bring attenuation by more than 20 dB and 50 dB over a narrow band and the entire passband, respectively. Therefore, in order to meet this requirement, a limiting device is implemented with multiple PIN-diode posts that enable the limiter to be the bandpass filter and stopband one at the off and on states of the PIN-diode switch, respectively. So, the design goes through the equivalent circuit modelling and the geometry is realized in the accurate electromagnetic analysis CAD tool. Finally, the result is discussed to shed light on whether it complies with the aforementioned requirement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.59-64
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• 2009

In this paper, the design of a new bandstop filter with an ultra-wide stopband is proposed using the metamaterial CRLH-TL. Instead of conventional periodic structures and multi-staged CRLH-TLs, extremely small one-cell type is adopted to circumvent the setbacks of conventional filters such as the lengthened ${\lambda}_g/2$-resonator ones or alternating impedance lowpass filter, and relatively slow skirt. Besides, for a very broad stopband, a strong coupling structure including stepped impedances is suggested and the zero-order resonance is made for effective size-reduction. The validity of the proposed design is proven through the fabrication and measurement, showing the overall size less than ${\lambda}_g/10$, the stopband wider than 12 GHz, 0.7 dB of the insertion loss.