• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.126-133
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• 2009

In this paper, The planar waveguide slotted antenna is presented for a satellite communication of vehicles. In stead of the microstrip patch array antenna having a dielectric loss and a feeding loss, the proposed antenna has the 3-layered waveguide feeding network structure for assembling easily. Also this antenna can receive mechanically both RHCP and LHCP transmitted from a satellite using a polarizer made from a thin single layer film. The Gain of the proposed 4X8 array antenna is 27.5dB and the gain of 8X16 array antenna is 32dB.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.12
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• pp.1-8
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• 2000

The analysis of cavity-backed circular microstrip antenna is performed, based on the method of moments, and verified with experimental results. The proposed algorithm was used to analyze the return loss and radiation characteristics of antenna by the variation of each associated parameter. This result was used to provide the optimum design guideline. Finally active reflection coefficient of infinite cavity-backed microstrip away was calculated to show the effect of suppressing surface wave to eliminate scan blindness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.807-811
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• 2001

In this paper we proposed a dual-frequency circular sector microstrip antenna with orthogonal polarized modes and high isolation between the two feeding ports. And then we designed a transceiver operating at 5.6 GHz for transmitting and at 5.5 GHz for receiving. The good isolation provided by the proposed antenna is used as the basis for the transmit-receive filtering of transceiver. The operating frequencies and polarization characteristics of the proposed antenna is calculated by using a cavity model. The 5-parameters and radiation patterns of the antenna are measured. A power amplifier and a low noise amplifier are designed and integrated with antenna to make a transceiver, which has about 13dB transmitting gain and about 8㏈ receiving gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1316-1324
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• 2009

In this paper, cross-aperture coupled microstrip circular polarization antenna is proposed for 5.8 GHz WLAN(Wireless Local Area Network). A single antenna consists of square patch and slots are located in series feed line with $\lambda_g$/4 phase different which make current direction maximum and minimum repeatedly to generate RHCP(Right Handed Circularly Polarization). We are proposed new structure that removed the section which intersected at a right angle and were composed to four separated slots. The proposed cross slots reduce back lobe of radiation pattern and improve antenna gain. Impedance bandwidth of the manufactured $2\times2$ array antenna is from 5.67 to 5.95 GHz and the maximum radiation gain is 10.59 dBi.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.3
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• pp.161-165
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• 2004

Exogenous carbon monoxide (0.2%) increases L-type calcium $(Ca^{2+})$ current in human jejunal circular smooth muscle cells. The stimulatory effect of carbon monoxide (CO) on L-type $Ca^{2+}$ current is inhibited by pre-application of L-NNA, a classical competitive inhibitor of nitric oxide synthase (NOS) with no significant isoform selectivity (Lim, 2003). In the present study, we investigated which isoform of NOS affected CO induced stimulation of L-type $Ca^{2+}$ current in human jejunal circular smooth muscle cells. Cells were voltage clamped by whole-cell mode patch clamp technique, and membrane currents were recorded with 10 mM barium as the charge carrier. Before the addition of CO, cells were pretreated with each inhibitor of three NOS isoforms for 15 minutes. CO-stimulating effect on L-type $Ca^{2+}$ current was partially blocked by N-(3-(Amino-methyl) benzyl) acetamidine 2HCl (1400W, an iNOS inhibitor). On the other hand, 3-bromo-7-nitroindazole (BNI, a nNOS inhibitor) or $N^5-(1-Iminoethyl)-L-ornithine$ dihydrochloride (L-NIO, an eNOS inhibitor) completely blocked the CO effect. These data suggest that low dose of exogenous CO may stimulate all NOS isoforms to increase L-type $Ca^{2+}$ channel through nitric oxide (NO) pathway in human jejunal circular smooth muscle cells.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.296-302
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• 2009

In this paper, a planar microstrip patch antenna is proposed using the slit on the top layer of a multi-layered structure for GPS application. The proposed antenna has a circular polarization at 1,575.42 MHz. This proposed antenna is fabricated on multi-layered FR4 substrate. The slits embedded on the top plane may yield to lower a resonance frequency and sustain a broad bandwidth. The proposed antenna size is $20{\times}20{\times}4.0\;mm^3$. The measured gain of 0.5 dBi, 10 dB bandwidth(VSWR 2:1) of 70 MHz(4.4 %), and 3 dB axial-ratio bandwidth of 15 MHz(1 %) have been obtained, respectively.

• Journal of electromagnetic engineering and science
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• v.5 no.1
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• pp.31-35
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• 2005

This paper presents low form factor dual polarized antenna incorporating low profile annular ring patch antenna having 90$^{\circ}$ phase delay element for circular polarization(CP) and a reactive-loaded monopole linear polarized(LP) antenna. Both types of receiving antennas operate in the same frequency region from 2.320 GHz to 2.345 GHz, while different polarizations are used to take advantage of polarization diversity. The proposed CP antenna has good broadside radiation patterns, while the LP antenna reveals monopole-like radiation patterns. The gains of the antennas are measured to be 1.93 dBi and 2.24 dBi for CP and LP, respectively.

• Journal of Advanced Navigation Technology
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• v.6 no.2
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• pp.113-118
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• 2002

In this paper, an internal GPS antenna for mobile phones is designed and fabricated. For the miniaturization of the antenna, high permittivity dielectric substrate((${\varepsilon}_r$=90) and small ground plane ($13mm{\times}13mm$) are used. To increase the receive gain, the antenna is composed with LNA(Low Noise Amplifier). Results of the manufactured antenna($13mm{\times}13mm{\times}8mm$) show that the maximum antenna gain is about 12 dBi, the axial ratio is less than 3 dB, and the current consumption of LNA is less than 4 mA.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.226-229
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• 2007

본 논문에서는 사각형 링을 갖는 UHF대 RFID 리더기용 소형 원편파 패치 안테나를 설계 제작하였다. 정사각형의 패치 안테나를 설계하고, 원편파를 위한 Truncated 패치 안테나를 설계한 후, 소형화를 위해 사각형의 링을 갖는 Truncated 패치 안테나를 설계하였다. 주파수 대역은 UHF대역인 902928MHz이며, 설계를 위하여 HFSS simulation올 사용하였다. 비유전율 4.3, 두께 1.6mm, 손실탄젠트 =0.019의 epoxy 기판을 사용하여 실현하였다. VSWR, 방사이득, RHCP, LHCP의 큰 변화없이 사각형의 링을 이용하여 기본 Truncated 안테나보다 6.37% 소형화시켰다.

• Structural Engineering and Mechanics
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• v.68 no.1
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• pp.17-38
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• 2018

In this paper, we compare and assess the performance of the standard 3- and 6-node MITC shell elements (Lee and Bathe 2004) with the recently developed MITC triangular elements (Lee et al. 2014, Jeon et al. 2014, Jun et al. 2018) which were based on the partitions of unity approximation, bubble node, or both. The convergence behavior of the shell elements are measured in well-known benchmark tests; four plane stress tests (mesh distortion test, cantilever beam, Cook's skew beam, and MacNeal beam), two plate tests (Morley's skew plate and circular plate), and six shell tests (curved beam, twisted beam, pinched cylinder, hemispherical shells with or without hole, and Scordelis-Lo roof). To precisely compare and evaluate the solution accuracy of the shell elements, different triangular mesh patterns and distorted element mesh are adopted in the benchmark problems. All shell finite elements considered pass the basic tests; namely, the isotropy, the patch, and the zero energy mode tests.