• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3623-3627
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• 2012

The modern society has become full-fledged entry into the information age since spread of Internet. 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 2.4GHz band which leads to saturation of the communication was significantly fall. Accordingly, the communication of the 5GHz band came to be interested. In this paper, we studied the design and fabrication of u-slot microstrip patch antenna to be used in wireless communication systems operating at around 5GHz band. To obtain antenna parameters such as patch size, inter patch space, antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, u-slot microstrip patch antenna is fabricated using FR-4 substrate of dielectric constant 4.4. The characteristics of fabricated antenna were analyzed by network analyzer.

• Composites Research
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• v.22 no.3
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• pp.55-59
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• 2009

Microstrip antennas are low profile, are conformable to planar and nonplanar surfaces, are simple and inexpensive to manufacture, mechanically robust when mounted on rigid surfaces and are compatible with MMIC(Monolithic microwave integrated circuit) designs; they have been used in diverse communication systems. The rectangular microstrip patch antenna is designed for a central frequency of 12.5 GHz, and the final product is a $4{\times}1$ array antenna with curvature radius of 200 mm. The microstrip antenna is embedded in a sandwich structure which consists of skin and core material. After impact, the performance of damaged antenna is estimated by measuring the return loss and radiation pattern. The antenna performance was not affected by this impact damage.

• 전자공학회논문지 IE
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• v.45 no.2
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• pp.13-19
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• 2008

The main advantage of the TLM analysis method is the ease with which even the most complicated transmission line structures. In this paper, using symmetrical condensed node(SCN), the TLM numerical technique has been successfully a lied to microstrip meander line. A detailed technique of the symmetrical condensed node(SCN) may be used to model planar microstrip transmission line is presented. Also, the S-parameters $S_{11}$ and $S_{21}$ of two types of microstrip meander line have been computed. From obtained results, TLM analysis is shown to be an efficient method for modeling complicated structure of planar microstrip transmission line. The TLM results presented here are useful in the design of microwave integrated circuits at higher frequencies region.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.658-663
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• 2013

In this paper, a microstrip line implementation using via transition and its application of multilayer compact ring hybrid coupler are presented. This transition is the sandwich structure with via hole to connect two microstrip lines in different layer. For designing a compact RF/Microwave passive circuit, the microstrip line using via-hole transition is proposed to reduce a size of microwave circuit with long transmission line. For the validation of the microstrip line with via-hole transition, the multilayer ring hybrid coupler is implemented at center frequency of 2 GHz. The measured performances are in good agreement with simulation results and about 50% size reduction compare to conventional ring hybrid coupler.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.306-313
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• 2012

In order to enhance the isolation level between two dual-band E-slot microstrip patch antennas, EBG structure which operates in UMTS Tx(1.92~1.98 GHz) and Rx(2.11~2.17 GHz) band is proposed. The proposed EBG structure made with a periodic array of two different size EBG unit cells which has a modified mushroom-type for isolation improvement between two antennas. They do not share a common ground plane of the microstrip patch antenna. Overall size of the fabricated antenna is $210.5mm{\times}117mm$. The two different EBG unit cell sizes are $15.6mm{\times}4mm$ and $17.4mm{\times}4mm$, respectively. It was etched on the FR-4 substrate(thickness=3.93 mm, ${\varepsilon}_r$=4.6). The experiment results show that the isolation level between antennas in Tx/Rx band were improved by about 9 dB and 12 dB, respectively, through the use of the proposed EBG structure.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.37-44
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• 2004

This paper describes a new GaAs-based surface-micromachined microstrip line supported by dielectric post and air-gapped signal line with ground metal. This new type of dielectric-supported air-gapped microstripline(DAML) structure is developed using surface micromachining techniques to provide easy means of airbridge connection between the signal lines and to archive low losses at millimeter-wave frequency band with wide impedance range. Each DAMLs with the length of 5 mm are fabricated and the measured characteristics are compared with those of the conventional microstrip transmission line. These transmission lines are composed of 10 ${\mu}{\textrm}{m}$ height of signal line, post size of 10 ${\mu}{\textrm}{m}$ ${\times}$ 10 ${\mu}{\textrm}{m}$ and post height of 9 ${\mu}{\textrm}{m}$. By elevating the signal lines from the substrate using the micromachining technology, the substrate dielectric loss can be reduced Compared with of the conventional microstrip transmission line showing 7.5 dB/cm loss at 50 GHz, the loss can be reduced to 1.1 dB/cm loss at 50 GHz.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.1-4
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• 2002

The present study aims to design a multiplayer microstrip antenna with composite sandwich construction and to estimate structural behavior of this multiplayer structure for the next generation of structural surface technology. This is termed Surface-Antenna-Structure indicating that structural surface becomes antenna. Constituent materials were selected considering electrical properties as well as mechanical properties. For the antenna performance, antenna elements inserted into structural layers were designed for satellite communication at a resonant frequency of 12.5 GHz and final demonstration article was $16\times16$ array antenna. From electrical measurements it was shown that antenna performances were in good agreement with design requirements. Structural analysis showed this antenna structure was well designed for the mechanical rigidity. All constituent materials were characterized independently. The SAS concept is the first serious attempt at integration for both antenna and composite engineers and promises innovative future communication technology.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.376-379
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• 2003

In this raper, proposed easy half-wavelength LPF and acceptor structure in actuality manufacture using EBG (Electromagnatic Bandgap) structure for application of micro-strip circuit. Because conventional half-wavelength LPF and acceptor is narrow line-width of High impedance, actuality manufacture is difficult. Width that in proposed structure narrow microstrip line of High impedance EBG structure use and has equal impedance embodied to wide microstrip line. Also, it is seen that actuality manufacture is available applying to half-wavelength LPF that have cut-off Frequency of 3GHz.

• Advanced Composite Materials
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• v.17 no.3
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• pp.215-224
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• 2008

The present study aims to design a multilayer microstrip antenna with composite sandwich construction and investigate fatigue behavior of this multilayer SAS (surface antenna structure) that was asymmetric sandwich structure for the next generation of structural surface technology. This term, SAS, indicates that the structural surface becomes an antenna. Constituent materials were selected considering electrical properties, dielectric constant and tangent loss as well as mechanical properties. For the antenna performance, antenna elements inserted into structural layers were designed for satellite communication at a resonant frequency of 12.2 GHz. From electrical measurements, it was shown that antenna performances were in good agreement with design requirements. In cyclic 4-point bending, flexure behavior was investigated by static and fatigue test. Fatigue life curve of the SAS was obtained. The experimental results of bending fatigue were compared with single load level fatigue life prediction equations and in good agreement. The SAS concept is can be extended to give a useful guide for manufacturers of structural body panels as well as antenna designers.

• Journal of information and communication convergence engineering
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• v.10 no.2
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• pp.123-128
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• 2012

In communication systems, there are various types of microstrip antenna that can be used for many applications. This paper mainly focuses on the simple design of an inset rectangular microstrip patch antenna to operate at a frequency of 2.45 GHz for rectenna design. The study involves using an high frequency structure simulator to design the antenna dimensions and to determine its performance. This antenna is based on a thickness of 1.6 mm flame retardant 4 (FR-4) substrate having a dielectric constant of approximately 4.7, an inset feed, and a ground plane. After simulation, the antenna performance characteristics such as its return loss, voltage standing wave ratio, gain, and radiation pattern were obtained and compared with the fabricated measured antenna.