• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.629-636
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• 2011

This paper presents the design of a novel integrated T-DMB/GPS/Mobile antenna for vehicular application. The T-DMB antenna is designed with a modified meander-type microstrip patch providing linearly a polarized broadside radiation pattern. The GPS antenna is designed with an inserted slot in the patch antenna providing circularly polarized broadside radiation pattern. The Mobile (GSM, AMPS, DCS, PCS, UMTS, etc.) antenna is designed as a modified G-type patch antenna providing multi-band operation. Experimental results indicate that the impedance bandwidth (VSWR 1:2.5) of the proposed T-DMB /GPS/Mobile antenna satisfactorily matches that of the simulation results. The 2D and 3D radiation patterns and gains according to the results of the experiment are also presented and discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.3
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• pp.279-287
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• 2002

In this paper, a symmetric microwave lens to steer wide angle and to operate at broad band frequency range for a linear phased array transmitter was designed. To get accurate beam steering performance far a linear phased array transmitter, uniform amplitude transmission characteristics of microwave lens was focused. The measured result for the insertion loss deviation between Input and output ports of microstrip lens with 8 beam ports and 8 array ports was $\pm$3.1 ㏈ over 6~18 ㎓ band, which was very uniform characteristics. Using 8 elements linear array antenna, it was confirmed the radiation beam could be steered over $\pm$60$^{\circ}$ in azimuth. And the measured lens performance data and multi-beam steering pattern were presented.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.292-299
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• 2012

This paper proposes the design of circularly polarized multi band antenna for a non-linear junction detector (NLJD) system. In order to design for broad bandwidth, the CPW (Co-Planar Waveguide) feeding method is considered in this design. In order to realize the circular polarization, the axial ratio was controlled by inserting a $45^{\circ}$ inclined slot on radiating element and by cutting an edge of the radiating patch. Measurement results of return loss, bandwidth, axial ratio, polarization pattern and gain are agreed well with their simulation results in interested frequency band at 2.4~ 2.44 GHz, 4.84~4.92 GHz, and 7.28~7.32 GHz.

• Journal of IKEEE
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• v.24 no.1
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• pp.90-96
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• 2020

As various communication services have emerged due to the development of mobile communication technology, there is a need for a wideband antenna supporting multiple communication services with one antenna. In this paper, we propose a planar slot wideband antenna that can support all the communication services of 3.1~4.99GHz, the low frequency band of 5G, in addition to the existing communication services such as WiFi, LTE 2300/2500, and WiMAX. Through the simulation, the optimized antenna design parameters were obtained, and the antenna was fabricated to implement an antenna with a frequency bandwidth of 1.96~6.01GHz (S11 <-10dB) and presented the radiation pattern and gain of the antenna. The proposed antenna is a multi-band antenna that can provide all the services of LTE, Wifi, WiMAX, and 5G low frequency bands. It can be used as a repeater antenna in radio shadow area such as buildings, dense areas, and ships.

• Journal of electromagnetic engineering and science
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• v.12 no.1
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• pp.101-106
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• 2012

In this study, we investigated the effect of groove pattern and gap-fill with lossy materials at 15 GHz frequency of Ku-band. We used Epoxy/MWCNT composite materials as gap-fill materials. Although epoxy does not have an absorbance capability, epoxy added conductive fillers, which are multi-walled carbon nanotubes (MWCNT), can function as radar absorbing material. Specimens were fabricated with different MWCNT mass fractions (0, 0.5, 1.0, 2.0 wt%) and their permittivity in the Ku-band was measured using the waveguide technique. We investigated the effect of gap-fill on monostatic RCS by calculating RCS with and without gap-fill. For arbitrarily chosen thickness and experimentally obtained relative permittivity, we chose the relative permittivity of MWCNT at 2 wt% (${\varepsilon}_r$=8.8-j2.4), which was the lowest reflection coefficient for given thickness of 3.3 mm at V-pol. and $80^{\circ}$ incident angle. We also checked the monostatic RCS and the field intensity inside the groove channel. In the case of H-pol, gap-fill was not affected by the monostatic RCS and magnitude was similar with or without gap-fill. However, in the case of V-pol, gap-fill effectively reduced the monostatic RCS. The field intensity inside the groove channel reveals that different RCS behaviors depend on the wave polarizations.

• Composites Research
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• v.35 no.6
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• pp.469-476
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• 2022

In this paper, the microwave absorbing characteristics after the impact of the radar-absorbing structure (RAS) consisting of periodic pattern sheet (PPS) and glass fiber-reinforced plastic (GFRP) were experimentally investigated. The fabricated RAS effectively absorbed the microwave in the X-band (8.2-12.4 GHz). In order to induce the damage to the RAS, a low-velocity impact test with various impact energy of 15, 40, and 60 J was conducted. Afterward, the impact damage was observed by using visual inspection, non-destructive test, and image processing method. Moreover, the absorbing performance of intact and damaged RAS was measured by the free-space measurement system. The experiment results revealed that the delamination damage from the impact energy of 15 J did not considerably affect the microwave absorbing performance of the RAS. However, fiber breakage and penetration damage with a relatively large damaged area were occuured when the impact energy was increased up to 40 J and 60 J, and these failures significantly degraded the microwave absorbing characteristics of the RAS.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1535-1541
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• 2005

Five broiler chicken lines, namely HC, BPB2, CPB2, PB2 and UM1, involving in a selection program and differing in selection intensity and genetic background, were screened for randomly amplified polymorphic DNA (RAPD) polymorphism using 10 selected decamer primers. Nine primers amplified the genomic DNA, generating 200 to 2,500 bp and all detected polymorphism between lines. Out of 74 bands scored using these primers, 34 (50.0%) were found to be polymorphic. The number of polymorphic loci ranged from 3 to 6 with an average of 4.33. Lines differed considerably for within-population genetic similarity estimated by band frequency (WS = 93.55 to 99.25). Between-line genetic similarity estimates based on band sharing as well as on band frequency ranged from 71.35 to 86.45 and from 73.38 to 87.68, respectively. Lines HC and PB2 were the most closely related to the other, while BPB2 and CPB2 appeared to be more distant from each other. The between-line genetic distance based on both band sharing and band frequency revealed the similar trends as for Between-line genetic similarity. Based on BS and BF criteria, BPB2 and CPB2 as well as PB2 and UM1 lines can be merged to launch a new genetic group for further progress in biometrical objectives. A phylogenetic tree, derived using Nei's coefficient of similarity revealed the different pattern of genetic distance between lines.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.535-540
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• 2004

In this paper, We proposed a rectangular slot antenna with CPW feeder. Slot antennas fed by CPW are attractive due to the simple fabrication simplicity and ease of integration with active devices. This antenna consists of two parts, inner patch and outer patch to realize wide-band antenna by multi-frequency. Also, We fabricated a proposed rectangular slot antenna, confirm characteristics of multi-frequency by tuning antenna parameters, inner antenna's location and size. The experimental results show that each resonant frequency of a fabricated antenna is measured at almost 1, 9GHz, 2.8GHz, 3, 5GHz, 4, 9GHz. In radiation patterns each resonant frequency, radiation pattern 4-th resonant frequency is the same ad that of TM11 in patch antenna. Therefore, the experimental and theoretical results shows that a proposal rectangular slot antenna have triple resonant frequencies.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.67-74
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• 2009

In this paper, the multi-band antenna with CPWG(Coplanar Waveguide with Ground) feed for telematics mobile devices is designed and fabricated. The proposed antenna improves the return loss characteristic by using open-circuited stub matching and rectangular slot in the radiation patch. In addition, CPWG structure makes up for the drawback of the CPW which is variation of impedance matching according to the gap variation of the feed line and the ground. The fabricated antenna has 1.4GHz ($1.43GHz{\sim}2.83GHz$, 65%) band width on -10dB (VSWR<2) and the maximum gains are 0.8dBi, 1.34dBi, 2.41dBi, 2.53dBi, 2.6dBi and 1.51dBi on each resonant frequency that are GPS $(1.564GHz{\sim}1.585GHz)$, PCS/DCS $(1.710GHz{\sim}1.984GHz)$, WCDMA $(2.170GHz{\sim}2300GHz)$, Bluetooth/Wi-Fi/WLAN $(2.4GHz{\sim}2.483GHz)$, WiBro $(2.3GHz{\sim}2.4GHz)$, SDMB $(2.605GHz{\sim}2.655GHz)$. It also has an omni-directional radiation pattern of H-Plane.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.5
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• pp.21-26
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• 2014

This paper proposes a frequency reconfigurable antenna which operates at not only LTE but also other currently serviced bands. The high band(1,710-2,170 MHz) performance was satisfied through PIFA structure, and the low band performance through the additional RF Switch by changing the state between SW1 and SW2. When the RF switch is SW1 state, the operation bandwidth is 782-907 MHz (GSM), and 738-861 MHz (LTE) at OFF state. The proposed antenna has a omni-directional radiation pattern and measured peak gains were 0.04-4.68 dBi at the SW1 state and 0.92-1.53 dBi at the SW2 state, respectively. Judging from the results, proposed reconfigurable antenna is expected to be applied to LTE-Advanced mobile terminals since the antenna shows an outstanding performance.