• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.8
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• pp.781-787
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• 2004

In this paper, a novel dual and wide band aperture stacked patch antenna for Cellular/PCS/IMT-2000 base station is presented. It consists of single microstrip patch having notches along the radiating patch, two dielectric substrates and a form material. To achieve wide band characteristic, we utilize the coupling effect between the notched patch and the resonant aperture in the ground plane and by properly cutting notches on the patch, an aperture stacked patch antenna could be designed to yield dual frequency operation. By the proper choice of resonant aperture size and height of a foam material, dual and wide band characteristic could be realized the measured impedance bandwidth(1:1.5 VSWR) of designed antenna at lower band(860 MHz) reaches 77 MHz and covers the Cellular CDMA band(824∼894 MHz). The measured impedance bandwidth(1:1.5 VSMR) of the designed antenna at upper band(1,960 MHz) is about 550 MHz and covers both the PCS band(1,750∼l,870 MHz) and the for-2000 band(1,920∼2,170 MHz). Good broadside radiation with high gain(5.65∼7.4 dBi) characteristics have also been observed.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.263-270
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• 2016

This paper implemented an ultra-wideband(: UWB) antenna by using a modified barrel-shaped patch antenna. The designed UWB patch antenna was optimized to match UWB technical specifications by considering the sizes of barrel circle and oval(notch) which is distance between the patch and contact surface and designed antenna was implemented by $10mm(R1){\times}21.8mm$ size. Optimal values on the basis of simulated reflective loss results, the surface current distribution of designed patch antenna was analyzed in order to check operation mode of antenna and wideband mechanism. Experimental results of implemented UWB antenna, Return loss of UWB antenna the voltage standing wave ratio was 2 or less in the 1.775-13.075 GHz band, VSWR in 2 or less. And the maximum gain of approx. 1-3 dBi was found in 3.1-10.6 GHz. This result satisfied the characteristics of ultra-wideband and the proposed antenna will be applicable to an ultra-wideband system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.583-591
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• 2012

In this paper, using a folded parasitic patch, a hybrid metamaterial antenna having the enhanced bandwidth is presented. To obtain a broad bandwidth of the antenna, a zeroth-order resonance(ZOR) mode of a mushroom antenna and a $TM_{010}$ mode of a conventional patch antenna are combined. By employing an etched rectangular hole and a folded parasitic patch in the conventional patch antenna, a resonance frequency of the $TM_{010}$ mode can be down-shifted toward that of the ZOR mode without changing the size of the antenna. Therefore, the proposed antenna has broad bandwidth which ranges from the ZOR mode to the $TM_{010}$ mode. As a result, a fractional bandwidth of the proposed antenna is measured as 12 % and a radiation efficiency is above 75 % in whole band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1269-1274
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• 2019

The paper presents a design of simple four-element microstrip-patch array antenna that is suitable for 5G applications. The proposed array consists of four rectangular microstrip patch elements with semicircular etches made on both sides of each elements. The antenna is fed using the combination of series and corporate feeding networks. The size of the ground is also changed to improve the antenna frequency. Finally, yagi elements are also added to improve the directive gain of the antenna. The presented microstrip patch array is able to achieve wide frequency bandwidth of 21.95-31.86 GHz. The antenna has also attained gain of 9.7 dB at 28 GHz and has maintained high gain and high directivity throughout the frequency band. The proposed array antenna fed by series-corporate feeding network, with low profile and simple structure is a good candidate for 5G applications.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.6 s.107
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• pp.14-22
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• 2005

The purpose of this paper is to assess conservation value of forests and cultivated areas from the landscape ecological point of view. The main focus of landscape ecology estimates the reciprocal relationships between spatial patterns and ecological processes. This paper sets the criteria for conservation value and classify the conservation value based on the criteria. Forests and cultivated areas in Seo-Gu, Incheon Metropolitan City was selected as the case study area. In this research, factors such as patch size and connectivity have been selected in order to consider the landscape ecological aspect, gradient for the environmental physics aspect and to consider the environment-ecological aspect, grade of environmental-oriented land suitability analysis Map developed by the ROK Ministry of Environment has been utilized. GIS methodologies have been adopted to calculate the relationships among the above variables. Through literature review, the following evaluation criteria have been adopted: (1) based on island biogeography and metapopulation dynamics theory, patch size criteria are set 2ha and 10ha; (2) connectivity was set the degree of connection with surrounding grids; and (3) gradient of 20 degrees. Conclusively, this paper suggests that local conditions, landscape ecology and physical environment aspects should be considered to develop an estimation framework of the conservation value.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.103-109
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• 2006

In this paper, single-feed equilateral triangular microstrip antennas(ETMA) for circular polarization(CP) are designed and studied experimentally. It is demonstrated that by embedding a narrow slot or a cross of unequal slot lengths in the triangular patch circularly polarized radiation RHCP(right-hand circularly polarized wave), LHCP(left-hand circularly polarized wave) of microstrip antennas can easily be achieved using by strategically positioned coaxial single probe feed. And the size of a triangular microstrip patch antenna is smaller than that of a conventional rectangular or circular patch at a given frequency. A single-feed ETMA with a horizontal narrow slot is printed on the substrate of 60 mils thick and the other ETMA with a corss slot of unequal slot lengths is printed on the same substrate. The antenna radiation characteristics are calculated by ENSEMBLE(Ver. 5.0) software, and compared with the experimental results. This results show that the antenna size reduction of about $17%{\sim}2l%$ is obtained as compared to the regular-size CP design.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.157-167
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• 2003

In this paper, to reduce the resonant length of patch, microstrip patch antenna of linear polarization which is suppressed at two radiation edges is designed and fabricated at the frequency of 1.575 GHz. The result is like that the resonant length of patch is 45 mm and the length reduction effect is 43.8 % when it is compared with that(80 mm) of plane type. The gain is 4.4 dBd and -3 dB beamwidths are 112$^{\circ}$ and 66$^{\circ}$ in the E-plane and H-plane, respectively. Also, to reduce the size of patch, microstrip patch antennas those are suppressed at four radiating comers are designed and fabricated at the same frequency in the linear and circular polarization, respectively. For linear polarization, at the 1.2 of width/length(W/L) ratio, the patch area is 53 mm $\times$ 63.6 mm and the size reduction effect is 56.1 % when compared with that(80 mm $\times$ 96 mm) of plane type. The gain is 4.3 dBd and the -3 dB beamwidths are 120$^{\circ}$ and 78$^{\circ}$ in the E-plane and H-plane, respectively. For circular polarization, the patch size(54.2 mm $\times$ 61.5 mm) is reduced by 47.2 % than that(76 mm $\times$ 83 mm) of plane type. -3 dB beamwidth of horizontal polarization in the z-x plane and vortical polarization in the y-z plane are 108$^{\circ}$ and 93$^{\circ}$, respectively and this means the increasement in both planes by 52$^{\circ}$ and 27$^{\circ}$ than those of plane type. The maximum gain is 2.5 dBd in the horizontal polarization in the z-x plane. Axial ratio is 1.5 dB at 1.575 GHz and the 2 dB axial ratio bandwidth(ARBW) is 20 MHz(1.3 %).

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.6
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• pp.98-109
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• 2011

Habitat restoration initiative is an important factor for the on-site preservation of butterflies. A new habitat necessitates the investigation of the ecology of the butterfly, the landscape of the habitat, the work process, and a cost analysis. In this study, these factors were analyzed through1) re-consideration of the secured results from three years of field work, and 2) a habitat area estimation conducted according to the presence or absence of larvae and adults via a Parnassius bremeri Bremer survey. The investigation of the natural habitat, done for both larvae and adult butterflies found in South Korea, suggested that multiple patches with a minimum size exceeding $300m^2$ and with an average size of about $1,600m^2$were required for survival of this butterfly. Therefore, more than five patches should be considered for butterfly habitat and patches should have similarity to the present habitat environment with transplantation plans for diet plants and honeydew plants. In addition, to activate the migration of the butterfly, cutting down trees that are obstacles to migration, minimizing the distance between patches and the addition of a stepping patch are also required. A patch connectivity analysis showed that patches should be located within 300m of neighboring patches, as the migration of the butterfly will fail if it is more than 600m. Additionally, more than $10,000m^2$ for a single patch or a patch network composed more than five patches over $1,600m^2$ in size were recommended, with a total patch size of $8,000m^2$. Additionally, neighboring multiple patch networks are more desirable than a single habitat in the event a cyclic habitat pattern arises. In this study, we suggest a habitat restoration and optimal prerequisites for a butterfly habitat. It is expected that this research will lead to the creation of a good model for the restoration of butterfly species.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.4
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• pp.539-544
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• 2017

In this paper, the broadband patch antenna for human counting systems is designed and fabricated using by the air dielectric substrate. Proposed antenna has a patch structure of the square structure with a 5 mm air layer and the vertical connection between the patch antenna and CPW feeding line is realized the stepped impedance structure. Optimized antenna through a 3D EM simulator is fabricated on a jig by manufacturing an antenna jig using a 3D printer with a size of 16.6 * 16.6 * 5 mm3. Proposed antenna is measured with the maximum gain of 5.71 dBi and the VSWR of below 2:1 at a frequency of 7.2 to 9.8 GHz. Also, a half power beam width characteristic of the antenna is measured $70^{\circ}$.