• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.9
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• pp.841-848
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• 2016

In this paper, a microstrip-fed dual-band monopole antenna with DGS(: Defected Ground System) for WLAN(: Wireless Local Area Networks) applications was designed, fabricated and measured. The proposed antenna is based on a microstrip-fed structure, and composed of two strip lines and DGS structure and then designed in order to get dual band characteristics. We used the simulator, Ansoft's High Frequency Structure Simulator(: HFSS) and carried out simulation about parameters W2, L10, W3, and DGS to get the optimized parameters. The proposed antenna is made of $21.0{\times}36.0{\times}1.6mm3$ and is fabricated on the permittivity 4.4 FR-4 substrate. The experiment results are shown that the proposed antenna obtained the -10 dB impedance bandwidth 700 MHz(2.10~2.80 GHz) and 1,780 MHz(5.02~6.80 GHz) covering the WLAN bands. Also, the measured gain and radiation patterns characteristics of the proposed antenna are presented at required dual-band(2.4GHz band/5.0GHz band), respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.765-770
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• 2009

This paper presents a new open stub structure of Kuroda low-pass filter using DGS(Defected Ground Structure). The open stub having 130ohm is made with equivalent new structure using DGS. This method enable to the fabrication of Kuroda low-pass filter by extending width of the line. In case of FR4(er=4.8, h=0.7874mm), the width of open stub(130ohm) is under 0.1mm. But, the width of open stub using DGS can extend to the width of 0.5mm. 5th order Kuroda low-pass filter design using open stub with DGS shows excellent agreement between theoretical simulation and experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.946-951
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• 2000

In this paper, we showed the characteristic of transmission line with DCS (Defected Ground Structure), which is etched on the metallic ground plane. And we extracted the equivalent element value of DGS section. Effects of a lumped element placed on DGS section were investigated by employing DGS of dumbbell shape and parallel resonator with DGS. Chip type resistor, inductor, and capacitor were chosen as lumped elements for experiments. Experimental results show that the Q-factor and resonant frequency of the proposed DGS section can be controlled directly by using the external lumped element.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.904-911
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• 2003

A new method to reduce the size of microwave amplifiers spiral-shaped defected ground structure(Spiral-DGS) is proposed. A microstrip line having Spiral-DGS on the ground plane produces increased slow-wave factor and electrical length for the fixed physical length. In addition, it provides an excellent rejection characteristic for a finite frequency band like band rejection filters. The rejection band is used for rejecting harmonic components of amplifiers. The reduced microstrip line lengths in matching networks by Spiral-DGS are 39 % and 44 % of the original ones in input and output matching networks, respectively. It is shown that the measured S-parameters of the reduced amplifier agree well with those of the original amplifier. The measured second harmonic of the reduced amplifier is much less than that of the original amplifier by at least 10 dB. The same technique is applied to reject the third harmonic using the proper Spiral-DGS for the third harmonic frequency. The measured third harmonic is smaller than that of the original amplifier by 25 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.117-123
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• 2006

In this paper, a CPW lowpass filter with the spurious-reduced characteristic is designed by using DGS(Defected Ground Structures). By cascading two lowpass filters with different harmonic characteristics the spurious is reduced below - 15 dB. Additionally by combining a dumbbell shaped DGS to the filter we achieved a satisfactory spurious level of less than -25 dB to above three times cutoff frequency without any repeated passband. The fabricated LPF shows a compact size of $17.2mm{\times}6.8mm$, a cutoff frequency of 6 GHz, and a sharp skirt response of 7-order with two notch frequencies. The measured frequency responses agree well with simulated ones.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3474-3481
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• 2013

In this work, a new high frequency transmission line structure combined with defected ground structure (DGS) and artificial dielectric substrate (ADS) structure is proposed. DGS patterns give add the additional inductance to transmission lines and results in the increased characteristic impedance for a given line width. To the contrary, ADS presents increased capacitance and reduced line impedance. So both play a role in reducing the length of transmission lines commonly, but in preserving the line impedance complementarily. This means that the length of transmission lines can be reduced furtherly by DGS and ADS without a critical change of line width compared to the cases when one of DGS and ADS is used only. As examples, $35{\sim}100{\Omega}$ transmission lines having DGS and ADS are designed, fabricated, measured, and compared to the simulation results. A good agreement between the simulated and measured line impedances is presented. In addition, the physical lengths of the proposed transmission lines are only 55.4~76.9% of those of the normal microstrip lines for the same electrical lengths.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.333-337
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• 2003

In this paper, 5.2 GHz WLAN BPF(Band Pass Filter) using LTCC(Low temperature co-firing ceramic) Multilayer technology was simulated and manufactured. A DGS(Defected Ground structure) resonator with spiral ground pattern is used to shorten resonator size and improve circuit Q factor. And the equivalent circuit of BPF was suggested. The measured result shows good agreement with simulated data. Experimental results show the center frequency of 5.25GHz, the insertion loss of 0.14dB, and the 3-dB bandwidth of 350MHz (6%). The center frequency of BPF is 5.25GHz which is available for wireless LAN.

• Journal of electromagnetic engineering and science
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• v.15 no.1
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• pp.26-30
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• 2015

In this paper, a simple equivalent circuit model for a defected ground structure (DGS) microstrip line with stepped impedance slot-lines in the ground plane is presented. In addition, an analytic expression for the resonance frequency of the proposed structure is derived. In equivalent circuit modeling, the capacitance and the inductance of the resonance circuit are evaluated from the dimensions of the etched pattern in the ground plane. The resonance frequencies calculated from the proposed method are compared with those obtained with an electromagnetic (EM) simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.42-49
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• 2018

In this paper, a dual-band microstrip-fed monopole antenna with a DGS(defected ground structure) for WLAN(wireless local area network) applications is presented. The antenna consists of a monopole and a defected ground, which were etched on both sides of the FR-4 substrate. The defected ground structure was used to obtain the dual band, while the step-by-step reduction in the monopole width was used to improve the impedance matching of the antenna. The antenna has an overall compact size of $44{\times}51{\times}1.6mm^3$, which was optimized by varying the size of the monopole and the ground plane such that it may resonate at the 2.4 GHz and 5 GHz bands of the WLAN. The measurement results showed that the antenna operates in the frequency band of 210 MHz(2.29~2.50 GHz) and 900 MHz(5.05~5.95 GHz) for a VSWR under 2, and showed omnidirectional radiation pattern at all desired frequencies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.1909-1913
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• 2008

In this paper, A compact ultra-wideband(UWB) bandpass filter(BPF) with WLAN notched filter has been proposed. H-shared slot is studied and adopted to tighten the coupling of inter-digital capacitor in order to improve the BPF's performance. Three pairs of tapered defected ground structures(DGS) are formed to assign their transmission zeros towards the out of band signal, thereby suppressing the spurious passband. Also Meander line slot is de#eloped to reject the undesired wireless local-area network(WLAN) radio signals. That's combining these three structures we obtain a small sized UWB BPF.