• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4537-4542
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• 2010

In this paper, the antenna radiation pattern inside the vehicle is presented for observing the change occurring in non-anechoic environment using monopole antenna. The environment for radio communication can be affected by antenna characteristic variation inside the small space existing multi reflection waves. To perform simulation and measurement about antenna radiation pattern, the radio frequency bands for GPS and Wibro services expected to use inside the vehicle is selected. The simulation is based on the ray-tracing method and the radiation pattern is measured inside the vehicle and in free space using monopole antenna having those frequency bands. In accordance with the measurement and simulation results, when two antennas are put inside the vehicle, the omni-directional characteristic of the antenna is maintained but the received power is increased than free space case and the difference between the each case of measurements is increased as the operating frequency is increased.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.8
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• pp.571-575
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• 2018

The moisture content of a coffee bean affects its permittivity, and changing the moisture content of a coffee bean changes the taste of the coffee. The variation in the moisture content of a coffee bean can be predicted by the change in frequency and reflection coefficient values with respect to the variation in the permittivity of the bean when it is placed on a patch antenna. In this study, a dual-band patch antenna is designed, which has a moisture measurement band of 3.8~4 GHz that can measure the moisture level of a material; the antenna has a Wi-Fi transmit and receive band of 2.45 GHz. Through simulations and measurements, this study proved that the level of return losses changed from 3.6 to 4 GHz when the moisture content of a coffee bean changed from 2 to 15%. The moisture levels of rice and other beans can be measured with the designed antenna, which can be applied to various applications.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.9 s.339
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• pp.65-70
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• 2005

For the base station or repeater which is in operation as part of a mobile communication system, any kind of degradation in antenna performance such as lowered gam or increased VSWR which maybe due to aging of antenna, connector corrosion or other environmental factors, is difficult to detect and react to immediately. In this paper, a VSWR measurement device which is capable of detecting the VSWR of a PCS forward path ($1,840\~1,870$MHz) antenna in operation in real time without any interruption in service is developed. Such regular measurement will allow the prediction of any serious failures and insure reliable operation of the antenna. All components of the antenna VSWR measurement device was researched so that the whole system could be produced and shown to be accurate in measuring the YSWR of an actual RF repeater in operation, proving it's effectiveness.

• Journal of electromagnetic engineering and science
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• v.15 no.4
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• pp.224-231
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• 2015

A comparison of the antenna parameters for R-band (1.7-2.6 GHz) and S-band (2.6-3.95 GHz) standard gain horn antennas has been performed by the Korea Research Institute of Standards and Science (KRISS), together with seven domestic participants from private companies and public institutions. Its purpose, as a proficiency test program of the 'Antenna Measurement Club' of KRISS, was to check equivalences in antenna parameter measurements between KRISS and the participants, particularly in the R-/S-band, to support antenna manufacturers and end users in Korea. The measurement parameters of this comparison are the power gain, radiation pattern, and reflection coefficient of the traveling standards for R-/S-band pyramidal standard gain horn antennas. The comparison used a gain comparison method and an extrapolation method to measure the power gain of the two traveling standards; the radiation patterns were measured in the far-field region of the transmitting and receiving antennas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.3
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• pp.243-250
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• 2002

This paper designed a compact printed meandered scot antenna which to integrate in wireless LAN and proposed a printed dual meandered slot antenna for improving bandwidth. A printed dual meandered slot antenna is calculated by using the mehtod of FDTD. The calculated results showed good agreement with the measured results. As a result of measurement, the bandwidth(VSWR< 2) of single meandered slot antenna is 115 MHz and the bandwidth of dual meandered slot antenna is 164 MHz. The dual meandered slot antenna bandwidth has been improves to that of 43% comparing to single meandered slot antenna.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.282-288
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• 2014

Recently there have been much interest in the GPS antenna performance improvement. In this paper, we propose very small patch antenna for GPS band. The proposed antenna resonance frequency was adjusted using the ground plane and variable capacitor connected the frame. The fabricated antenna was used a FR4 substrate by considering the difficulty and economical efficiency. Antenna measurement results was obtained good characteristics of VSWR 1.2, the passive antenna gain -0.60 dBi, the active antenna gain of 29 dB in center frequency of 1575.42 MHz GPS band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2345-2350
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• 2014

In this paper, measurement methods for the characteristics of antennas for indoor digital TV (DTV), having 75-ohm port impedance, are introduced. Reference impedance of typical radio frequency (or microwave) systems and measurement equipments is 50 ohm. However, the reference impedance of antennas for indoor DTV is 75 ohm, and the characteristics of the antennas cannot be measured directly using the measurement equipments. Measurement methods, using test equipments with reference impedance of 50 ohm, for the characteristics(impedance, radiation patterns, and gain) of antennas designed to fit for 75 ohm port are introduced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.45-46
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• 2014

In this paper, measurement methods for the characteristics of antennas for indoor digital TV (DTV), having 75-ohm port impedance, are introduced. Reference impedance of typical radio frequency (or microwave) systems and measurement equipments is 50 ohm. However, the reference impedance of antennas for indoor DTV is 75 ohm, and the characteristics of the antennas cannot be measured directly using the measurement equipments. Measurement methods, using test equipments with reference impedance of 50 ohm, for the characteristics(impedance, radiation patterns, and gains) of antennas designed to fit for 75 ohm port are introduced.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.10
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• pp.761-768
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• 2017

In this paper, to implement the electromagnetic wave environment and solve electromagnetic compatibility(EMC) problem, miniaturization of ultra-wide band log periodic dipole antenna for measurement was investigated. In addition, in oder to improve the signal-to-noise ratio in high frequency band, balun was connected to the antenna to stabilize the operation of the differential mode antenna and the single mode coaxial cable. To minimize the total size and to increase bandwidth of the antenna, a fat dipole structure was used for the resonance frequency band below 4 GHz and a general dipole shape was used for that above 4 GHz. The bandwidth of the proposed antenna was represented from 0.6 GHz to 8.0 GHz with a ratio bandwidth of 12.3 : 1. Measured peak gain varies from 5.7 dBi to 9.1 dBi, and a half power beamwidth was presented from $29.4^{\circ}$ to $100.2^{\circ}$ in operating range.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.4
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• pp.170-175
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• 2004

A three dimensional feed horn 10${\mu}{\textrm}{m}$ wavelength infrared antenna has been suggested, fabricated and characterized. It was applied to an infrared detector for efficient collecting of IR radiation and for reducing background noise. The horn antenna size was designed for maximum antenna directivity. The 3D feed horn antenna mold was fabricated using rotating and tilted illumination while the antenna plate was constructed by way of electroplating. Antenna characteristics were measured by coupling with a microbolometer. Measurement results indicated that the directivity of the antenna is 16.1㏈ and the background noise is reduced by approximately two times.