• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.636-639
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• 2008

The paper deals with the improvement of various characteristics of antenna for VHF mobile handset. In the general case, $1/4{\lambda}$ monopole and helical antenna are used for VHF mobile handset. However, various characteristics of antenna have different result for effect of hand. Especially, radiation efficient is reduced about several dB. In this paper, characteristics of loaded helical antenna have been evaluated. And we propose a method to improve a radiation efficient of antenna consider with hand effect.

• ETRI Journal
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• v.37 no.2
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• pp.204-211
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• 2015

For this study, we designed an implantable rectangular spiral antenna for medical biotelemetry in the Medical Implant Communications Service band (402 MHz to 405 MHz). The designed antenna has a U-shaped loop for impedance matching. The antenna impedance is easily adjusted by controlling the shape and length of the U-shaped loop. Significant design parameters were studied to understand their effects on the antenna performance. To verify the potential of the antenna for the desired applications, we fabricated a prototype and measured its performance in terms of the resonant characteristics and gain radiation patterns of the antenna. In the testing phase, the prototype antenna was embedded in human skin tissue-emulating gel, which was developed to simulate a real operation environment. The measured resonant characteristics show good agreement with the simulations, and the -10 dB frequency band is within the range of 398 MHz to 420 MHz. The antenna exhibits a maximum gain of -22.26 dBi and an antenna efficiency of 0.215%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.9
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• pp.879-885
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• 2014

In this paper, we designed and fabricated wideband 3-axis isotropic antenna for the Electro-Magnetic Fields(EMFs) measurement. Each part of proposed 3-axis antenna has isotropic characteristics and arbitrary axis of proposed 3-axis antenna could be selectable using RF switch. Also, a resistor was inserted in each axis of proposed 3-axis antenna for improving antenna gain and noise suppression characteristics, and port impedance of each dipole antenna were matched by balun. For the performance verification of antenna, GTEM Cell which generates standard electromagnetic field was used for the derivation of antenna factor and receiver sensitivity. As a result, fabricated 3-axis isotropic antenna has receiver sensitivity of 0.12~4.2 mV/m and typical VSWR of 3.3:1 within a wide operation frequency range from 0.03 MHz to 3 GHz.

• 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 information and communication convergence engineering
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• v.7 no.4
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• pp.449-452
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• 2009

In this paper, a novel compact and wideband fylfot-shaped planar monopole antenna is proposed. The fylfot-shaped is suggested to reduce the volume of a general crossed planar monopole antenna. The volume of the proposed antenna is about 1/4 of a general crossed planar monopole antenna under the conditions where the wideband characteristics are maintained. This technique is suitable for the design of wideband planar monopole antenna which needed a small volume.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.4
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• pp.219-225
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• 2000

In this paper, we report the experimental setup and characterization of experimental results for the HTS antenna. The constructions of experimental setup must be fabricated, cautiously. We constructed the cryostat made of 3 stages which consists of radome, vacuum stage and helium refrigerator for the HTS antenna. The HTS antenna was mounted to cryostat and various characteristics were measured at room temperature and liquid nitrogen temperature, 77 K. Also the results for the HTS antenna and the gold antenna were compared in terms of reflection coefficient, E-plane and H-plane radiation pattern, input impedance, SWR and efficiency. It appeared that the HTS antenna was superior to gold counterpart over the all characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1895-1901
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• 1999

The characteristics of a disk-loaded cylindrical dipole (DLCD) antenna that determine its performance are analyzed by using the method of moments. The current integral equation that is considered with extended boundary condition is derived. Numerical results for the input impedance and radiation pattern of the antenna are presented. The antenna factor with the antenna gain is computed to check the possibility of using this antenna as the broadband antenna for the special case in such as electromagnetic compatibility testing. The comparisons of the computed results with measured data are made. These results will allow this antenna to be used with confidence in various applications.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.632-637
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• 2012

Antenna equipment is transported being assembled to moving equipment and often subjected to vibration and shock excitation during transportation. In these circumstances, structural safety of antenna equipment must be secured. Wire rope isolators are assembled between moving equipment and antenna equipment to reduce the level of vibration and shock. In this paper, a isolator that are suitable to the system is selected and dynamic characteristics analysis of driving on antenna equipment is conducted using real system and the result is compared with response analysis. Also modal test of array-antenna pack-assembly is conducted and structural safety of that is secured by reinforcing its structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.130-135
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• 2005

In this papers, we made study for plastic chip antenna, the plastic is Foamex with the circle of PVC and its electric characteristics are dielectric constant 1.9, insulation intensity 112 KV/cm. The proposed antenna is same as the conventional antennas are usually constructed with ceramic chip, which are not fragile in nature and don't tend to break easily. Therefore the proposed antenna with its advantage is attractive for application in mobile antenna. In order to valid the proposed papers, it is implemented the antennas of four types and experimented. From the results, we conformed that the antennas are operated at the dual band which is cellular band and Korea-PCS band. And the gain of the antennas has about above -2 dB and the pattern is same as conventional antennas. From this papers, the realized antennas using Foamex material will be application for mobile phone antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.3
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• pp.329-339
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• 1999

LPXDA(Log-Periodic X Dipole Antenna), consisting of X dipole elements, was proposed as a Log-periodic antenna with short boom length and good Performance relative to LPDA(Log-Periodic Dipole Antenna) . LPXDA for operating frequency band of 500 MHz~l,000 MHz was designed and radiation characteristics of the designed antenna was analyzed by moment method, and compared with LPDA characteristics. The proposed LPXDA, in this paper, was found to have shorter boom length by 20% and better radiation characteristics with variations of frequency relative to the LPDA. The calculated results show good agreement with measurements.