• Journal of IKEEE
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• v.21 no.3
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• pp.219-226
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• 2017

This paper was studied the double-band monopole antenna design with Mu-negative metamaterial unit cell, which operates at 700MHz and 2.45GHz band. Mu-negative unit cell made of the interdigital capacitor structure to operate a double-band antenna by inserting it into an antenna radiator unit. In addition, the parasitic conductor is implemented on the back side of the antenna radiation part, so that the resonance point of the antenna can be controlled and the bandwidth is improved. Finally, we implemented an antenna operating in the 750MHz UHD band and the 2.45GHz WiFi band. The designed antenna has a size of $200{\times}100mm^2$. Experimental results show that the 8dB bandwidth and gain characteristics at 750MHz band are 320MHz(42.7%), 5.28dB, 6dB bandwidth and gain at 2.45GH are 540MHz (21.6%), -0.46dB. From the experimental results, we confirmed that the resonance point with theoretical value is in agreement with experimental value, and the radiation patterns are have the omnidirectional characteristic in both bands.

• Journal of IKEEE
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• v.21 no.3
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• pp.248-251
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• 2017

In this paper, The proposed board is developed by EMI compliant Dash Camera with $360^{\circ}$ omni angle. The proposed board is designed by designing DM and CM input noise reduction circuit and applying active EMI filter coupling circuit. The DM and CM input noise reduction circuit design uses a differential op amp circuit to obtain the DM noise coupled to the input signal via the parasitic capacitance(CP). In order to simplify the circuit by applying the active EMI filter coupling circuit, a noise separator is installed to compensate the noise of the EMI source to compensate the CM and DM active filter simultaneously. In order to evaluate the performance of the board for the proposed EMI response, an authorized accreditation body has confirmed that the electromagnetic certification standard for each frequency band is satisfied.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1082-1088
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• 2006

A turnstile antenna using the parasitic monopole has been developed for STSAT-2 TT&C application. The antenna consists of two radiating elements; a bow-tie dipole and a parasitic monopole. The bow-tie dipole is main radiating element, used a bow-tie structure for bandwidth improvement and size reduction. The parasitic monopole improved beamwidth and axial ratio. The input impedance of the antenna is about 50 ohm without a matching circuit. The proposed antenna has beamwidth of $>140^{\circ}$, axial ratio of < 3 dB and VSWR of < 1.5 in the band of $2.075{\sim}2.282GHz$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.726-733
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• 2010

This paper propose the printed inverted-F antenna using the coupling feed for the mobile phone. The coupling feed can normally leads the additional capacitances in the antenna, so the high inductive reactance of the antenna can be partly compensated. In this paper, it is shown that the bandwidth of the proposed antenna using the coupling feed is improved at $824{\sim}960$ MHz and $1,710{\sim}2,390$ MHz. Then it is compared with the simple direct feed to confirm the improvement of the bandwidth. The proposed antenna covers GSM850/GSM950/DCS/USPCS/WCDMA/Wibro and has the maximum gain of －$4.794{\sim}1.648$ dBi and shows omnidirectional patterns over the operating bands.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.9
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• pp.1285-1291
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• 2013

In this paper, a double circular ring monopole antenna for wideband applications is designed and fabricated. The proposed antenna is based on a planar monopole design, and composed of double circular ring of radiating patches and ground plane to obtain the wideband characteristics. To get the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator(HFSS) and found the parameters that effect antenna characteristics. Using the obtained parameters, the proposed antenna is fabricated. The fabricated antenna is measured at the operating frequencies, and the return loss coefficient, gain, and radiation patterns are determined. The results of measurement, -10dB impedance bandwidth, measured return loss is 4,530 MHz(2,510-7,040 MHz) and antenna peak and average gains for the frequencies are obtained 0.71~3.38 dBi, -3.85~0.3 dBi, respectively. In case of radiation patterns, the proposed antenna displays nearly omnidirectional radiation characteristics in the E-plane, and monopole-like radiation pattern characteristics in the H-plane.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.265-272
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• 2011

This study designed and manufactured "a DVOR virtual signal generator" to make the monitoring system of preliminary Doppler VHF Omni-directional Radio Range(DVOR) run like its real operation status in a narrow space in order to study "a DVOR virtual monitoring system". The designed and manufactured DVOR virtual signal generator is suitable for the specification of signal that is generated in the currently running equipment. In addition, it is possible to control operation conditions of equipment by using parameter variables, and the circuit construction is largely divided into the input part, the modulation part, the high-gain amplifier, and the power part. "The DVOR virtual monitoring system using the virtual signal designed and implemented in this study is very suitable to be used for low-cost actual education as it can construct the operation status like the real situation in a narrow space without using an actual system like an antenna generating side band.

• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.7-20
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• 2002

This study deals with the distribution and morphological study of the neurons with the neuropeptide Y (NPY) in developing chick brain. The developing brains of Korean native chicks at embryonic days 8 (E8), E10, E12, E14, E16, E18, and E20 were used. The chicks were perfused with 4% paraformaldehyde through the left ventricle and aorta. The brains were removed and transferred into 30% sucrose, and then cut in a cryostat into $60{\mu}m$ in thickness. The sections were immunostained with free-floating and avidin-biotin complex (ABC) methods. The numerous neurons with NPY were first observed in nucleus rotundus of diencephalon at E8. In particular, neurons in nucleus rotundus had the well-developed processes. At E12, the neurons with NPY were distributed widely in diencephalon; nucleus septalis lateralis, medialis, nucleus magnocelluaris preopticus dorsalis, medialis, ventralis, nucleus preopticus medialis, nucleus dorsolateralis anterior thalami pars magnocellularis, and nucleus paraventricularis magnocellularis (paraventricular nucleus) except nucleus rotundus. From E12 to E20, positive neurons were oval-shaped, changed gradually into the spherical- and multipolar-shaped. The shapes of processes were also omnidirectional and the number of those were less than in telencephalon. As the chicks developed, the morphology of neurons with NPY showed the tendency to increase in their sizes and numbers.

• Journal of Korea Multimedia Society
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• v.10 no.9
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• pp.1165-1174
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• 2007

Mobile ad hoc networks suffer from the re-construction of the routing path as a node on the path moves away and/or fails. In this paper we propose a multipath routing scheme, designed for the network based on the directional antennas, in which a new path is quickly recovered by do-touring to an alternative neighbor called braid. Simulations are conducted in random networks with 50 nodes uniformly deployed in a $1,000m{\times}1,000M$ area where, all nodes have a transmission range of 250m and the average node moving speed varies from 0 to 10m/s. The proposed approach under the ideal antenna with K(>1) directional sectors achieves better results compared with the case of K=1, the omnidirectional antenna model, in terms of the metrics: packet delivery ratio and average number of hops for the routing paths. As further study, a scheme to alleviate the heavy amount of latency accompanied by the rout setup is urgently required.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.489-496
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• 2019

In this paper, we design and fabricate an ultra small dual crossed dipole antenna operating at 2.4 GHz frequency. In order to miniaturize the size of the antenna so that it can be applied to a mobile device, a cross dipole is disposed on the upper two layers and a reflection plane, a horizontal matching circuit and a ground plane are arranged on each layer. The circuit was connected by a vertical through-hole. The size of the fabricated antenna is $21.61mm{\times}16.88mm{\times}1.27mm$, the measured reflection coefficient is -31.5 dB, and the bandwidth below -10 dB is 112 MHz. In addition, since the gain of the antenna is -4 dBi, it has the omnidirectional radiation characteristic, so it can be applied to various fields as an antenna for mobile devices.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.223-228
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• 2021

In this paper, we proposed a slot-type antenna with microstrip feed embedded in a PCB for Zigbee communication (2.4 ~ 2.484 GHz). The proposed antenna is designed on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 50×65 mm². Through simulations, trends of design parameters are analyzed and optimized, and the proposed antenna composed with three slots satisfy the frequency band. The measured impedance bandwidths (|S₁₁| ≤ -10 dB) of fabricated antenna are 900 MHz (2 ~ 2.9 GHz) in Zigbee frequency band. In addition, the radiation pattern showed omnidirectional characteristics for E and H-planes, and the gain of antenna in Zigbee frequency band was 1.782 dBi.