• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1662-1667
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• 2012

This paper describes the design of size-reduced ring hybrid couplers (RHC) using a common defected ground structure (CDGS). The proposed RHC consists of double-sided microstrip line and the CDGS patterns which are placed in the common ground plane of the double-sided microstrip line. The effects of DGS as a periodic structure are imposed on both microstrip lines, so the advantages of the existing DGS are doubled. The normal RHC is designed first and folded by the half reference plane with the CDGS realized on the common ground plane. So another trial for size-reduction is performed by folding the RHC and inserting CDGS besides to the conventional DGS. In order to show a design example, a 2GHz RHC is designed and miniaturized using CDGS. The size of the miniaturized RHS is around 50% of the normal one, while the performances are well preserved even after the size-reduction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2298-2304
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• 2011

This paper describes and presents the design of a miniaturized low pass filter (LPF) for microwave frequency region using a common defected ground structure (CDGS). In this study a half-sized LPF is obtained using CDGS, while the previous LPFs with the conventional DGS showed a mild size-reduction. The common DGS (CDGS) is realized on the common ground plane of two microstrip lines, i. e double-sided microstrip lines, which exist back-to-back to each other. In order to show the validity of the proposed design, an example of LPF using CDGS and double-sided microstrip lines is designed, fabricated and measured using the dielectric substrate with the dielectric constant of 2.2 and with the thickness of 31mils. The size of the designed LPF using CDGS is only 52.6% compared to that of the previous LPF with the conventional DGS. In addition, it is shown that the performances of the proposed LPF are well preserved after the size-reduction with the measured S11 and S21 of -22dB, min and -0.19dB, max, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.308-308
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• 2009

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1670-1671
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• 2011

본 논문에서는 고주파용 소신호 증폭기 소자와 공통결함접지구조(common defected ground structure, CDGS)를 이용하여 초고주파 증폭기를 설계한다. 공통 결함접지구조를 이용하면 종래의 DGS를 이용하는 경우보다 증폭기 회로의 크기를 더 줄일 수 있다. 회로 설계 도구인 ADS와 전자기 시뮬레이터인 HFSS를 이용하여, common defected ground structure를 지니는 소형화된 증폭기 회로가 설계된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2443-2448
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• 2013

In this paper, a design of size-reduced microwave oscillator using common defected ground structure (common DGS) is described. At first, an oscillator is designed using the normal stub resonator, and the conventional DGS patterns are inserted for the first trial of size-reduction. Finally, the DGS resonator section is folded by half size in order to adopt the common DGS, and this produces the proposed size-reduced oscillator. Common DGS pattern is inserted for a better size-reduction than when conventional DGSs are used. The folded transmission line is connected using the 3-dimensional signal via-holes. For an example of design, a 2.1GHz oscillator is designed and fabricated using a small signal transistor and common DGS, which shows the size-reduction of 11 mm. The measurement shows 6.7dBm of output power and -133dBc/Hz@1MHz of phase noise. The measured performances are so similar to those of the oscillators before size-reduction and prove the proposed size-reduction method of oscillators using common DGS.

• Journal of the Korean Vacuum Society
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• v.18 no.6
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• pp.403-410
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• 2009

Vacuum chambers have wide application for a variety of purposes such as material processing, vacuum gauge calibration, etc. As the dynamic pressure generated in such chamber is non-uniform, in many industrial as well as research processes, it is vital to know the non-uniform gas distribution with associated gas flow regimes and the ways of minimizing these pressure non-uniformities. In the present work, the behavior of gas flow in a vacuum chamber, during continuous gas flow, is described in the pressure range 0.1-133 Pa and the effect of baffle plate in minimizing the pressure non-uniformities is investigated. It was observed that maximum deviations in the pressure occur near the gas inlet point and that the effect of baffle plate in minimizing the pressure non-uniformities is more obvious in the transitional flow regime.

• Journal of the Korean Vacuum Society
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• v.16 no.4
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• pp.244-249
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• 2007

Deadweight piston gauge have been widely used as a fundamental instrument of precise pressure measurement because they are robust, accurate, potable, convenient to use and are able to realize the definition of pressure as farce per unit area. Basically, a deadweight piston gauge consists of a piston mounted vertically in a close-fitting cylinder filled with a gas and weights of known mass values. The pressure to be measured is applied to the base of the piston generating an upward vertical force, and is balanced by the downward gravitational force generated by weights. These instruments can be used to measure pressures above 10 kPa because of tare weights including piston. However, using a variable bell-jar pressure method and a newly developed weight loading device we can extend the application range of deadweight piston gauge to lower pressures. In this paper, we present the practical calibration results for two CDGs(Capacitance diaphragm gauge, MKS) with full-scale ranges of 1.33 kPa and 13.3 kPa, respectively.