• 전기의세계
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• v.14 no.1
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• pp.26-34
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• 1965

The radiation patterns and impedance of the half wave solt on the wide side of rectangular wave guide are analyzed. The measuring methods and procedures are described. And that the experimental data of the pattern and impedance of the slot are presented which are consistent with the theoretical values. The causes of error are also considered and are believed to be tolerable for the pattern and input impedance measurements. The usefulness of the slot antenna tested are also described.

• 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.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.43-49
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• 2008

Motivated by the Communication Broadcasting Convergence service, various technical approaches are being used to develop more efficient antenna models. This paper proposes a compact mobile antenna which is attachable to a cell phone and is applicable for Communication Broadcasting Convergence. In the design of the antennas for mobile handsets, size reduction is a crucial factor. In this paper, the compactness of a loop antenna is realized by bending a folded-dipole. A short planar dipole is transformed to a twice folded dipole and a loop antenna to produce a larger input resistance. The current distribution of the antenna is the same as a loop antenna, and its radiation patterns are omni-directional. We also analyze the performance of the RFID antenna by exploring the current-induced near field radiation patterns using a electro-optic field mapping system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.1 s.92
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• pp.84-91
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• 2005

In this papers, we study the characteristics of dual band PIFA(Planar Inverted F antenna) for handy phones using H-type silt in the antenna radiators. Slit types on the antenna radiator vary resonance mechanism of the antenna and affect reactance component of impedance for the antenna. Therefore the antennas resonate at the dual band(cellular -band, Korea-PCS band), the bandwidth, input impedance and radiation patterns of the proposed antenna is affected by the silt length on the radiators. In order to demonstrate the validity of the proposed theory, it is implementation the antenna of the 4 types. From results for the experiment of the implementation antenna, -5 dB bandwidth of return loss is content with the allocated bandwidth of Cellular and Korea-PCS system the gains of the antenna is about -8$\~$ - 1 dB, the radiation patterns for x-polarized or y-polarized are omnidirectional pattern. From above the results of this papers, it is conclude mobile phones antenna for handy phones using this papers results.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.1-10
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• 1999

In this paper, the design for the shaped offset cassegrain antenna system combined with corrugated feed horn is presented. First, spherical-mode wave theory is applied to the corrugated conical horn and its radiation patterns are investigated. Using the radiation patterns, design data of the corrugated conical horn are obtained by efficiency investigation of horn antenna. When the investigation is completed, the flare angle and length of the corrugated conical horn is determined. Next, the main and sub-reflector is designed using Snellis law and the conservation principle of energy. Then the uniform direction and energy density of the traveling wave at the aperture of the main-reflector is obtained. The maximum size of the main-reflector is determined by investigation of the illumination and spillover efficiency. Finally, the curvature of the main-reflector is modified to satisfy the condition of the uniform phase. From the calculated efficiencies, the designed site of the main-reflector and sub-reflector, system gain of the shaped offset cassegrain antenna has been obtained 40.5dB in Ka-band frequency. It has better characteristics than the result of SABOR with 39dB gain.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.172-176
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• 2008

This paper presents a novel feeding structure of the triple-band internal antenna which covers CELLVLAR/DCS/US-PCS bands. The proposed antenna consists of a U-slot patch radiator with a shorting post connected with ground plane and symmetric feeding lines with respective a feeding and shorting posts on both faces of the fixed FR-4 substrate. Through the simulation and experimental results, the proposed antenna is confirmed to have the features of less interference with a human head/body, broad bandwidth, desirable radiation patterns and efficiency for triple-band applications.

• Journal of electromagnetic engineering and science
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• v.1 no.1
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• pp.37-42
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• 2001

This paper presents the basic characteristics of a cutoff cavity-hacked slot antenna, for the application of spacetenna, with a feed post and a parasitic post inserted parallel to the slot. This type of antenna might effectively excite the slot and forcibly resonate the cavity by adding external reactance to the parasitic post. The Galerkin\`s method of moments is used to analyze integral equations for the unknown electric current on each post and electric field in the slot. The value of external reactance for forced resonance is discussed by deriving a determining equation, the current distribution on each post and the radiation patterns are considered. The analysis is in excellent agreement with the experiment for the radiation patterns.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.282-287
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• 2003

″H″ type resonator has the advantage for the miniaturization of high-T7 superconducting (HTS) microstrip antenna in comparison with the conventional microstrip antenna such as rectangular type or circular type. In this paper we designed miniaturized HTS antennas using this "H"-type resonator and reported the characteristics of our antennas including return loss, bandwidth, radiation patterns, efficiency and so on. To fabricate the "H" type antenna, HTS YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) thin films were deposited on MgO substrates using rf-magnetron sputtering. For comparison between normal conducting antennas and superconducting antennas, the gold antennas with the same dimension were also fabricated. An aperture coupling was used for impedance matching between 50 $\Omega$ feed line and HTS radiating patch. The ″H" type superconducting antenna showed the performance of 1.38 in SWR, 26 % in efficiency, and 13.8 dB in the return loss superior to the normal conducting counterpart.

• Journal of electromagnetic engineering and science
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• v.5 no.2
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• pp.97-103
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• 2005

This paper describes the measured results of sonobuoy transmitting antenna system for anti-submarine warfare (ASW). Since radiation pattern and power density depend on impedance matching between transmitting RF part and antenna with termination resistance, design of matching circuit is very important for sonobuoy system performance. Matching circuit is designed by Smith chart using control of L and C. In standing wave ratio(SWR) measurement using Network Analyzer, SWR of antenna with matching circuit observed 1.5 below at the assigned VHF band. It shows very excellent performance comparison with conversional product that is used for the same object. The measured vertical and horizontal radiation patterns are also shown the satisfaction of military specifications. A drop out of sonobuoy system on the sea is happened when angle of elevation direction is over 10 degrees, and it is conformed that it takes less than I second return to original signal level. The required electric power density is $83\;mW/m^2$ in the military specification, and measured electric power density is observed over average $110\;mW/m^2$ at all frequency bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1094-1101
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• 2001

The design of a compact folded patch antenna with moderately broad bandwidth is presented in this paper. The proposed antenna has radiation characteristics that are similar to the conventional monopole antenna. However, since this antenna is designed in a planar form, it has smaller size than that of a conventional monopole antenna. We have investigated the resonance frequency and bandwidth characteristics of the proposed antenna by changing the antenna design parameters. The proposed planar form of a monopole antenna in this paper has 1.17 GHz bandwidth with a matching circuit at the center frequency of 6.05 GHz.