• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.3
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• pp.68-73
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• 2011

In this paper, a compact-narrow open stub band-pass filter with parasitic-signal of low frequency range and second harmonics rejected using the parallel coupled line and FLCLM(Frquency Locked Controlled Length Method) is proposed. The characteristic of the parallel coupled line can be rejection for parasitic-signal of low frequency range and second harmonics. In last filter of experimental results show that insertion loss is 1.2 dB and return loss is 14.8 dB, and the fractional bandwidth is 10 % at the center frequency of 5.8 GHz. In additional, the rejection for parasitic-signal of low frequency range and second harmonics are 28.9 dB and 28.8 dB, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1271-1278
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• 2007

A novel frequency multiplier using composite right/left-handed transmission line is proposed. The left-handed transmission line in the proposed frequency multiplier suppresses the fundamental component($f_0$), while the composite right/left-handed ${\lambda}/4$ open stub diminishes unwanted harmonics. Due to the combination of the left-handed transmission line and composite right/left-handed ${\lambda}/4$ open stub, the only desirable multiplied frequency component such as 3 $f_0$ and 4 $f_0$ are obtained at the output port excellently. For the example of the proposed design, frequency multipliers are designed at 1 GHz of $f_0$ and measured. The measured output power of 3 $f_0$ and 4 $f_0$ is -5.67 dBm and -6.43 dBm, respectively, when the fundamental input power was 0 dBm.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.38-47
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• 2008

In this paper, the narrow band-pass filter with compact-size using the ${\lambda}g/2$ open stubs is proposed. The filter size is reduced by realization of transmission line at second harmonics and at the same time the power can be transferred to the output by using the fundamental wave generated in the resonator and the transmission line in which the impedance mismatch technique is adopted. Thus, the proposed filter can be reduced to half-length of horizontal transmission line than the conventional one. The experimental results show that insertion loss is 1.58 dB and return loss is 9.86 dB, and the fractional bandwidth is 10 % at the center frequency of 5.8 GHz. The filter size is $10.34{\times}18.56\;mm2$.

• 한국ITS학회:학술대회논문집
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• v.2006 no.10
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• pp.187-190
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• 2006

In this paper, the equivalent circuit of tapped-line that is applied in the feeding of the band-pass filter with high coupling is suggested and the value of an equivalent circuit is mathematically defined. An equivalent circuit of tapped-line is composed by open stub and additional transmission line, and the electrical lengths of stub and line can be obtained by the impedance of resonator and the inverter. The new equivalent circuit of tapped-line can be simply applied of design of band-pass filter and leads to very good agreement compared with theoretical value. The coupled-line band-pass filter using equivalent circuit of tapped-line shows the insertion loss of 1.97 dB and the return loss of 18.5 dB at the center frequency of 5.8 GHz.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.57-62
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• 2023

This paper proposes a tri-band bandpass filter using dual-mode stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with open stubs and parallel coupled lines (PCLs) that have inter-digital and comb-line shorted ends. Two U-shaped SIRs with open stubs build the first and third passband, and the central PCL resonators build the second passband. Five resonators and coupling structures are theoretically analyzed to derive the scattering parameters of the proposed filter. A novel tri-band bandpass filter is designed and fabricated using the induced scattering parameters. The measured result of the fabricated tri-band bandpass filter shows a good agreement with the simulated one.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.467-474
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• 2019

In this paper, we studied a method for a broadband stacked patch antenna structure which is widely used for bandwidth improvement. The characteristics according to the distance between the two patches were analyzed and the impedance matching was optimized by connecting parallel open stubs to the main patch feed line. The shunt matching stub is inserted underneath the parasitic patch and so it does not require additional space, which enables the proposed antenna structure to be advantageous in miniaturizing antenna. The effects of the various parameters on the antenna performance are examined, and we introduced the design procedure for the proposed antenna to operate in the frequency range of 2.3~2.7GHz. Experimental results show that the bandwidth of the proposed antenna is about 480MHz with 2.27~2.75GHz bandwidth. And the antenna gain was 5.8dBi at 2.3GHz and 7.8dBi at 2.6GHz within the bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.4
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• pp.379-385
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• 2002

In this paper, frequency trifler fur 8 GHz local oscillator was designed and fabricated using MESFET. The third order harmonic was generated by biasing the transistor on A class. The fundamental frequency and the second harmonic were suppressed by using λ$\_$g//2 stub and band pass filter. As results, conversion gain of 2.67 ㏈ at 8.31 GHz, the harmonic suppression of -41.17 ㏈c, the bandwidth of 510 ㎒ were measured.red.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.247-251
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• 2001

본 논문에서는 MESFET을 이용하여 2670MHz에서 8010MHz로 주파수를 체배하는 Frequency Tripler를 설계 및 제작하였다. A급에 동작점을 두어 3차 하모닉 성분을 발생시켰고, λ$_{g}$/4 개방형 스터브와 대역통과 필터를 이용하여 기본주파수와 2차 하모닉성분을 억제하였다. 측정결과 0dBm의 입력신호에 대해 출력주파수인 8.16GHz에서 변환이득은 -0.33dB, -55dBc의 기본 주파수 억압, -33dBc의 2차 하모닉 성분의 억압을 얻었다. 2.5GHz～2.84GHz의 입력주파수에서 400MHz의 사용대역을 얻었다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.6
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• pp.22-25
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• 2010

This paper presents the modified design that can reject the harmonic signals in the branch-line coupler. After adding open stubs at the center of quarter-wavelength lines of the traditional design, all network parameters can be determined by network equivalence, in order to maintain the conventional function at the operating frequency and suppress its harmonic terms to de chosen. Experimental results show the second and third harmonic suppressions to be -37.5 and -42.7dBs, while maintaining conventional performance at the fundamental frequency.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.84-90
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• 2011

In this paper, a dual-band pseudo-combline narrow bandpass filter is proposed. The proposed bandpass filter adopts the open resonant stubs and the proposed bandpass filter can be used for ITS(Intelligent Transport System) and X-band satellite systems application. The proposed bandpass filter has the insertion and return losses of 1.72 dB and 15.5 dB at the bandwidth of 3.6 % and center frequency of 5.8 GHz, respectively. Also, the second operating frequency band for insertion and return losses are 1.92 dB and 16.3 dB at the bandwidth of 3% and center frequency of 8.5 GHz, respectively.