• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.10 s.89
• /
• pp.938-943
• /
• 2004

In this paper, we propose a T-shaped DGS for CPW and provide the closed-form solutions for power loss rate, and bandwidth of the DGS. The proposed T-shaped DGS structure has a range of capacitance(C) 5.5 times wider than the dumbbell-shaped DGS structure. In addition we also analyze relations between R, L, C values of the DGS equivalent circuit and total loss rate, BW, $\omega_0$ of the DGS.

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

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.9
• /
• pp.1039-1046
• /
• 2007

In this paper, a coupled-defected ground structure(C-DGS) using negative inductive coupling is proposed and a bandstop filter(BSF) using C-DGS is designed and fabricated. The proposed C-DGS is the closely-located DGS cells for the negative coupling, the negative coupling of ground currents between adjacent DGS cells greatly improves the stopband characteristics. The proposed BSF utilizing the sharp cutoff response of the C-DGS has a -10 dB rejection band from 4 GHz to 11.3 GHz. A maximum attenuation rate is -64.3 dB/GHz in 3 cell structure, -108 dB/GHz in 5 cell structure. The C-DGS BSF shows the improved attenuation rate 3.8 times in 3 cell structure, 2.4 times in 5 cell structure, Also, the C-DGS BSF is reduced to 35.2 % and 40 % of the DGS BSF, respectively, due to the closely-located DGS cells. We fabricated the single gate mixer using C-DGS BSF. The single gate mixer has 6.6 dB conversion gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.7 s.110
• /
• pp.673-683
• /
• 2006

In this paper, we investgate variation of phase and magnitude characteristics which become different as the variables of DGS are changed and propose the new method to easily decide the best optimum DGS pattern taking advantage of this trend. Generalized Chebyshev(GC) low pass filter(LPF) is designed by using DGS obtained from this method GC DGS LPF is more available for filter application than Chevyshev DGS LPF because GC LPF have parallel resonators as series circuits, therefore unlikely Chebyshev LPF, transform step of the series elements can be omitted. By using the proposed method, GC DGS LPF(N=5) and as a subject of comparison, conventional Chbyshev LPF(N=7) are designed and implementation. From the comparison of the measured data, we confirmed that the implemented GC DGS 5th order LPF have much better cutoff characteristics and reduce by 0.58 times size, on the other hand the stop bandwidth become widen about 1.57 times or more in comparison with the conventional Chevyshev 7th order LPF.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.8 no.4
• /
• pp.257-262
• /
• 2015

In this paper, the split-ring DGS resonator is proposed and its equivalent circuit are analyzed to design the low pass filter. Compared with the conventional dumbell DGS cell, this structure has a flat fluctuation in low frequency range and a sharp slop at edge frequency. The out-band suppression of the SRR-DGS cell can be improved by placing the open stubs on the conductor line which operates as parallel capacitances. Making use of equivalent circuit analytical method, the characteristics of the improved SRR DGS cell are investigated and applied to design compact low pass filter, which has a low in-band loss, sharp slop and high suppression of more than 35dB within a wide out-band frequency range. The dependence of the transmission characteristic on the dimension of a split ring, such as side-length and split-gap, is analyzed in detail. In addition, an improved SRR DGS cell model with open stubs loaded on the conductor line is then presented to improve the out-band suppression. By using the equivalent-circuit analytical method, an S-band microstrip low-pass filter with perfect low-pass characteristic and high out-band suppression is designed and fabricated.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.12
• /
• pp.2589-2594
• /
• 2012

In this paper, a novel resonator using ring type DGS is proposed for improvement of phase noise characteristics that is weak point of oscillator using planar type microstrip line resonator, and oscillator for 5.8 GHz band is designed using proposed DGS resonator. The ring type DGS resonator is composed of DGS cell etched on ground plane under $50{\Omega}$ microstrip line. At the fundamental frequency of 5.8 GHz, 7.6 dBm output power and -82.7 dBc@100kHz phase noise have been measured for oscillator with ring type DGS resonator. We designed the voltage controlled oscillator using proposed the DGS resonator with varactor diodes placed between gaps of DGS. Thus, due to its simple fabrication process and planar type, it is expected that the technique in this paper can be widely used for low phase noise oscillators for both MIC and MMIC applications.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.8
• /
• pp.1416-1421
• /
• 2008

A 10 dB branch line hybrid coupler included with defected ground structure (DGS) is proposed. In this contribution, a contact between the grounded metal housing and DGS is avoided, which has been a serious problem in applying DGS to high frequency circuits. An isolation between the metal housing and the DGS pattern is provided by inserting additional substrate between DGS and the metal package. Therefore, it is possible to design branch line hybrid couplers having highly asymmetric power dividing ratio using these DGS structure, which is demonstrated in this paper. The designed and fabricated branch line hybrid coupler using DGS is well packaged in a metal housing without touching the ground metal directly. The measurement is performed under realistic practical operating situations because it is packaged in a metal housing. The measured performances of the fabricated 10dB coupler shows a 1:9 asymmetric power dividing ratio at output ports, as predicted. In addition, the measured performances in terms of matching, isolation, and phase difference are in excellent agreement with the simulated characteristics.

• Journal of information and communication convergence engineering
• /
• v.6 no.1
• /
• pp.51-54
• /
• 2008

The defected ground structure (DGS) for microstrip structure can be used to protect analog/RF signal from SSN interference of digital circuits on PCB with common ground. However, the basic DGS gives rise to undesired emissions that may interfere with nearby circuitry due to the ground discontinuity. In this paper, we have proposed the modified structure, Corrugated DGS and the method to reduce the radiation by adding the lumped resistor on the proposed Corrugated DGS.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.380-383
• /
• 2003

In this paper, we analyzed the characteristics of a modified DGS(Defected Ground Ground Structure)and extracted the equivalent citcuit of that. The proposed DGS is the structure that connects two DGS units, which are composed of the defects on the metallic ground plane and the gab on the signal line. The gab on the signal line was adopted to induce series capacitor of band pass filter. Also, to confirm the validity of the proposed structure, we designed and implemented C - Band pass filter by using the modified DGS.

• The Mathematical Education
• /
• v.43 no.2
• /
• pp.177-186
• /
• 2004

In this paper, we introduce new functional definitions for school geometry based on DGS (dynamic geometry system) teaching-learning environment. For the vertices forming a geometric figure, we first consider the relationship between the independent vertices and dependent vertices, and using this relationship and educational considerations in DGS, we introduce functional definitions for the geometric figures in terms of its independent vertices. For this purpose, we design a new DGS called JavaMAL MicroWorld. Based on the needs of new definitions in DGS environment for the student's construction activities in learning geometry, we also design a new DGS based geometry curriculum in which the definitions of the school geometry are newly defined and reconnected in a new way. Using these funct onal definitions, we have taught the new geometry contents emphasizing the sequential expressions for the student's geometric activities.