• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.599-604
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• 2021

In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, efficiency and performance of 2.4 and 5GHz band which leads to saturation of the communication was significantly fall. In this paper, we studied the design and fabrication of slot patch antenna to be used in wireless communication systems operating at around 10GHz band. To obtain optimal antenna parameters such as patch size, inter patch space, sL, sW, feed L, feed w, slot patch antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, slot and patch antenna is fabricated using FR-4 substrate of dielectric constant 4.4. The characteristics of fabricated antenna were analyzed by network analyzer. The fabricated slot patch antenna showed a center frequency as 10.23GHz, the minimum return loss as -32dB, and -10dB bandwidth as 420MHz respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1744-1751
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• 2006

In this paper shows the Designed and Manufactured active antenna for wireless LAN that is consisted of 5.5GHz band local LNA and Microstrip Patch Antenna. LNA improved noise special quality using NEC company's NE3210S01 and Micnstrip Patch Antenna designed to have omnidirectional characteristic. Designed $1{\times}2$ Microstrip Patch Antenna to have the gain of about 8.3[dBi], the input reflection loss -32[dB], VSWR showed 1.132, and the LNA gain 15[dB], input-output reflection loss was showed the characterstic of -20[dB].

• Journal of KIISE:Information Networking
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• v.28 no.1
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• pp.143-153
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• 2001

본 논문에서는 에드-혹 망의 멀티캐스트 라우팅 프로토콜인 ODMRP(On-Demand Multicast Routing Protocol)를 확장한 PatchODMRP를 제안한다. ODMRP는 네트워크 상에서 멀티캐스트그룹의 송신원으로부터 수신원에 이르는 경로 상에 있는 노드들을 FG(Forwarding Group) 노드로 선출하여 이들이 해당 멀티캐스트그룹에 속하는 패킷을 모두 플러딩하도록 함으로써 멀티캐스트 그룹데이타 전송을 담당하는 메쉬를 구성하도록 하는 방안이다. 그런데 ODMRP는 주기적으로 이 메쉬를 구성하는 FG 노드들을 재 선정하기 때문에 이 주기가 길어지면 메쉬 구성이 네트워크 노드들의 이동성을 따라가지 못해 메쉬분리가 발생하고 데이터가 손실될수 있다. 반면에 이 주기를 짧게 하면 오버헤드가 지나치게 커질수 있다. 특히 송신원의 수가 적은 경우 ODMRP의 메쉬는 매우 성기게 형성되는데 이때 호스트들의 이동성이 크면 메쉬 연결을 유지하기 위하여 이 주기를 짧게 잡아주거나 높은 데이터 손실율을 감수해야한다. 본 논문에서는 이 문제점을 해결하고자 각 FG 노드들이 BEACON 신호를 이용해 자신에 인접한 메쉬에 손실이 발생한 것을 인지하고 이를 국부적인 플러딩을 통하여 빠르게 복구하는 메커니즘을 ODMRP에 추가한 PatchODMRP 방식을 제안한다. 시뮬레이션을 통하여 기존의 ODMRP와 제안하는 PatchODMRP의 성능을 비교한 결과 PatchODMRP가 호스트의 이동성에 훨씬 강하며 ODMRP에 비하여 낮은 오버헤드로 높은 데이터 전송률을 제공할 수 있음을 보여주었다.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.48-58
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• 2015

The bandwidth enhancement of an aperture coupled microstrip patch antenna(ACMPA) with a high permittivity feed substrate suitable for the integration with MMIC is investigated using variation of an aperture width. As an aperture width increases, the 10 dB return loss bandwidth increases due to the increase of the mutual resonance region between a patch resonance and an aperture resonance. The bandwidth of an ACMPA with extended aperture width is increased up to 35.3 % from 20.8 % of the ACMPA with an aperture of a typical aspect ratio 10:1. The degradation of the radiation characteristics of an ACMPA due to the increase of an aperture width is very small.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1600-1606
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• 2001

Resonant frequency in rectangular microstrip patch antenna on anisotropic substrates with airgap and superstrate are analyzed. Dyadic Green function is derived for selected anisotropic material by constitutive relation. From these results, integral equations of electric fields are formulated using Fourier transform in space region. The electric field integral equations are discretized into the matrix form by applying Galerkin\`s moment method. Sinusoidal functions are selected as basis functions because they resemble in the actual standing wave on the patch. To verify the validity of numerical result, we compare our result with existing one and get a good agreement between them. From the numerical results, the resonant frequency in the variation of air gap, patch length and anisotropy ratio are presented and analysed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.591-597
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• 2003

In this paper, a compact and broadband PIFA(Planar Inverted F Antenna) which has an additive short-circuit plate along the patch length was designed. For more compact PIFA short-circuit Plate along the patch width is reduced and an additive short-circuit plate along the patch length is used to broaden the bandwidth. The effect of an additive-short-circuit plate along the patch length was verified in single band PIFA and also verified in dual-band PIFA. The commercial software, IE3D, was used to design a PIFA and its performance was verified by comparing simulated results with measurement results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.265-269
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• 2005

In this paper shows the Designed active antenna for wireless LAN that is consisted of 5.5GHz band local LNA and Microstrip Patch Antenna. LNA improved noise special quality using NEC company's NE3210S01 and Microstrip Patch Antenna designed to have omnidirectional characteristic. Designed Microstrip Patch Antenna expressed omnidirectional characteristic special quality having gains of about 8.3dBi. LNA gains 15dB, noise index showed special quality under 1 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1604-1611
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• 2003

For dual­band operation, it can be done by loading two pair of slits in the equilateral­triangular patch, one embeded close to the side edges of the patch and the other inserted at the bottom edge of the patch. The frequency ratio of the two operating frequencies can be tuned by varing the positions and lengths of the inserted slots at the bottom edge of the patch. While the calculated frequency ratio of the antenna by Ensemble 5.0 is $1.66 ({f_10}=1.928GHz, {f_20}=3.2GHz)$, the measured one is 2.04 $({f_10}=1.6806 GHz, {f_20}=3.435 GHz)$. The error in the frequency ratio is due on the fabrication dimension and feeding position error as well as on the permittivity dispersion effect.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2066-2072
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• 2014

In this paper, We proposed a UWB microstrip patch antenna with an O-shaped slot of the step structure and analyzed the characteristics of the antenna. In order to improve of frequency properties, size of the patch radiating element, radius change of the O-shaped slot, width of the feed line and a rectangular slot were optimized by CST simulation program. The proposed antenna showed that the 2.8GHz ~ 11.4GHz frequency, the minimum return loss and -10dB bandwidth were -32.39dB and 8.6GHz, respectively.

• ETRI Journal
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• v.31 no.5
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• pp.554-564
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• 2009

In information security and network management, attacks based on vulnerabilities have grown in importance. Malicious attackers break into hosts using a variety of techniques. The most common method is to exploit known vulnerabilities. Although patches have long been available for vulnerabilities, system administrators have generally been reluctant to patch their hosts immediately because they perceive the patches to be annoying and complex. To solve these problems, we propose a security vulnerability evaluation and patch framework called PKG-VUL, which evaluates the software installed on hosts to decide whether the hosts are vulnerable and then applies patches to vulnerable hosts. All these operations are accomplished by the widely used simple network management protocol (SNMP). Therefore, system administrators can easily manage their vulnerable hosts through PKG-VUL included in the SNMP-based network management systems as a module. The evaluation results demonstrate the applicability of PKG-VUL and its performance in terms of devised criteria.