• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1175-1180
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• 2014

In this paper, the open ring type DGS(Defected Ground Structure) resonator, applicable to MMIC(Monolithic Microwave Integrated Circuit), is proposed to improve phase noise characteristics of RF oscillator. This resonator is planar type, therefore, it easy to design miniaturrized., and takes relatively high Q value. Modeling the equivalent parameter of resonator is needed, when designing the RF oscillator with resonator. The mathematical method to solve the equivalent parameter of the resonator from the measured results of resonator is introduced in this paper. To verify the method, DGS resonator with 5.8 GHz center frequency is fabricated, for measuring characteristics and calculating the equivalent parameter. The result from this process is compared with the data of the ADS simulation, and as a result both were identical.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.12
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• pp.2589-2594
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• 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 C
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• v.54 no.2
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• pp.91-96
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• 2005

In this letter, we proposed a novel DGS (Defected Ground Structure) microstrip resonator. The proposed DGS resonator has the resonant and anti-resonant characteristic that is very similar to those of a SAW resonator or a FBAR. In order to confirm the validity of the proposed resonator, we designed and implemented bandpass fitters by using series ana parallel resonators.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1581-1586
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• 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 5.8GHz 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 5.8GHz, 7.6dBm output power and -82.7 dBc@100kHz phase noise have been measured for oscillator with ring type DGS resonator. The phase noise characteristics of oscillator is improved about 9.5dB compared to one using the general ${\lambda}/4$ microstrip resonator. Because it is possible that varactor diode or lumped capacitor is placed on the gaps of ring type DGS, resonant frequency can be controlled by bias voltage. We can design voltage controlled oscillator using proposed ring type DGS resonator. 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 Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2A
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• pp.147-152
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• 2005

In this paper, we have proposed a novel DGS(Defected Ground Structure) resonator and has designed the band -pass filter using the proposed ${\subset}$ stub-I type DGS resonator. This structure has strong advantages that can vary the retune loss at the passband freely and also can easily tune the attenuation pole frequency at the stopband. The bandpass filter can be made more smaller than the existing filters and be used to find the various applications for eliminating the harmonics and spurious mode at IMT-2000 band.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.3
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• pp.182-186
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• 2004

In this paper, 2.4GHz WLAN BPF(Band Pass Filter) which has two DGS(Defected Ground Structure) unit cells was simulated and manufactured. To do this, a unit DGS resonator with resonant frequency is designed. Then the BPF for WLAN with the center frequency of 2.4GHz md the bandwidth of 200MHz is designed using two DGS resonator, finally this circuit is fabricated. We also proposed the equivalent circuit of the BPF employing two DGS resonator. The BPF with DGS was obtained experimental results with network analyzer Agilent 8510C. The measured result shows good agreement with simulated data. Experimental results show the center frequency of 2.45GHz, the insertion loss of 1.08dB, and the 3-dB bandwidth of 470MHz(19.5%). Acceding to the measured values, it is found that the fabricated DGS BPF is available for wireless LAN.

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

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.4
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• pp.59-64
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• 2009

In this paper, we represent characteristics and equivalent circuit of donut type resonator of defected ground structure (DGS), and can control resonant frequency with chip capacitor. In General, DGS operates like with parallel LC resonator. We found out variation of resonance frequency when capacitor is placed on slot of DGS. If the chip capacitor replace with varactor diode, the resonance frequencies can be controlled by voltage. This tualable resonator can apply to voltage controlled oscillator and tunable bandpass filter.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.4
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• pp.243-248
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• 2015

Since phase noise is one of the most important parameters in the design of microwave oscillators, several methods have been proposed to reduce the phase noise. These methods have focused on improving the quality factor of resonators, which result in low phase noise oscillators. Dielectric resonators have been widely used for low phase noise in microwave oscillators due to their high quality factor. However this cannot be used in MMIC oscillators because they have a 3D structure. In this paper, to overcome this problem a novel resonator using open 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 5.8GHz band is designed using proposed DGS resonator. The open ring type DGS resonator is composed of DGS cell etched on ground plane under $50{\Omega}$ microstrip line. At the fundamental frequency of 5.8GHz, 6.1dBm output power and -82.7 dBc@100kHz phase noise have been measured for oscillator with ring type DGS resonator. The phase noise characteristics of oscillator is improved about 96.5dB compared to one using the general ${\lambda}/4$ microstrip resonator.

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