• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.249-254
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• 2014

We have studied on the possibility of railway stability system using RFID tag. UHF RFID tag was desinged, manufactured and tested. Proposed UHF tag antenna has PIFA type structure and inset feed multi matching technique was attempted for impedance matching of antenna. The impedance bandwidth (VSWR < 3) of the proposed tag antenna covers 917~923 MHz. Measured peak gain is 3.225 dBi and UHF band with an omni-directional radiation pattern. RFID reader and tag installed in motor car and track, respectively. Then, tag recognition rate according to velocity of car (under 45 km/h) represented 100 %.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.101-110
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• 2007

This study has designed a circular polarization antenna for UHF bandwidth RFID reader. As a result of performance test of the antenna designed it is found that return loss (S11) is about -45.529dB at 914MHz, which is relatively small, and antenna gain is about 6.09dBi. It has also been confirmed that $50{\Omega}$ impedance matching is about $50.48{$\Omega}$ and it can be applied to every RFID reader. Therefore, the antenna is designed to have higher gain of circular polarization by improving reception, which is one of the most important parameters of RFID reader and is expected to be extensively used to recognize multi-tag in the distance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.1-6
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• 2008

A wearable T-matching dipole UHF RFID tag antenna has been designed using conductive electro-thread. The conductivity of the electro-thread has been measured depending on the number of twisted thread. The measured conductivity has been used for simulation to have accurate simulation results. The flexible electro-thread or fabric has been used for fabricating the antenna instead of using copper tape since the electro-thread is more flexible and wearable than copper tape. The return loss and reading range of the fabricated electro-thread UHF RFID tag antennas have been tested. The reading range is approximately 2.4 m.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.57-58
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• 2018

In this paper, we studied a design method for a quasi-Yagi antenna operating over a broad bandwidth covering the UHF RFID(902-928 MHz) and GNSS(1,164-1.605 MHz). The proposed antenna is composed of three elements(dipole, reflector, and director) and fed by a coplanar waveguide. To reduce its size, a balun is integrated inside the antenna, and the ends of both the dipole and reflector are bent. Broadband impedance matching was obtained by placing the director near to the dipole and loading a chip capacitor inside the antenna. The antenna, designed through simulations, was fabricated on an FR4 substrate with 0.8 mm thickness. The experiment results for the antenna characteristics agree very well with the simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.891-895
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• 2010

A dual-band (UHF: 470-862 MHz, L: 1452-1492 MHz) digital video broadcasting-handheld (DVB-H) antenna is presented. The proposed antenna is composed of a planar inverted F-shape antenna (PIFA) with an input impedance matching circuit. The matching circuit improves antenna performance in the broad UHF bands (470-862 MHz: 63%). The proposed antenna has omni-directional patterns and sufficient gain (Ave. peak gain is about 1.70 dBi over 470-862 MHz) for the PMP applications. The antenna is contact with a PMP case (${\varepsilon}_r=3.2$) which is used as a substrate for the size reduction and compact design.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.4
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• pp.320-323
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• 2018

Herein, an ultrawideband spinning direction finding (DF) antenna was designed and fabricated for airborne applications. The proposed antenna is designed by dividing the low-band (UHF - L band) and high-band (S - Ka band) antennas to cover the ultrawideband frequency range (UHF - Ka band). For the high-band antenna, an LPDA antenna fed offset-parabolic-reflector antenna is applied. In the low-band antenna, two LPDA antenna elements are arrayed in front of the reflector of the high-band antenna without increasing to the full antenna size. The low- and high-band gains of the fabricated antenna were measured as 8.76 dBi and 24.55 dBi on average, respectively. The antenna was fabricated with the dimensions of 437 mm in diameter and 358 mm in height. Consequently, we confirmed that the designed antenna is appropriate for the spinning DF antenna in terms of the affordable size for installing on an airplane, as well as the high gain and narrow beamwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.204-210
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• 2005

In this paper, we are proposed the antennas for RFID tag operated at UHF band which are inserted ground plane easy to mount the RFTD chips at the antenna surfaces. In order to implemented antenna for RFID tag which the size is same as conventional name card, the structure of the antenna is meander type, matching method for improvement characteristics of the antenna use T matching method, ground plane is inserted at the antenna substrate fer mounting RFID chips. The substrate size of implementation is $100\times60\;mm^2$ and the FR4 substrate is used. Results of the experiment, the center frequency of the implemented antenna is 427 MHz, -10 dB return loss bandwidth is 8 MHz, maximum return loss is 21 dB, the radiation pattern is omnidirectional. From these results, we are conformed application for UHF RFID tag antenna.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.67-71
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• 2012

This paper represents the impact analysis results of antenna reflector for the UHF-band antenna of Space Launch Vehicle. Three types of UHF-band antenna reflector model have been proposed and simulated to compare their characteristics such as resonance frequency, reflection loss and radiation pattern etc. Simulation results showed that resonance frequency and return loss of each reflector models were rarely affected even if reflector sizes are changed. The antenna gain and 3dB bandwidth were slightly changed to the worse directions as the reflector sizes are smaller.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.46-51
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• 2013

In this paper, the optimum placement and shape of UHF antenna on the unmanned aerial vehicle (UAV) are analyzed by using the electromagnetic (EM) simulation on the various locations. The FEKO was used for the EM-simulation. In order to reduce the complexity of simulation and minimize the runtime and memory usage, the composite aircraft structure is simplified as the PEC model excluding the radome structure. The simulation was performed on the wing and ventral fin of UAV, and the antenna shape used the monopole, dipole, and bent monopole antennas. When the monopole antenna is mounted under the wing, two antennas need to be mounted under the right and left wings, and those antennas have to be switched as the direction of UAV wing to the line of sight (LOS) data-link (DL) ground antenna. In the case of mounting under the ventral fin, one antenna can be used regardless of the direction of UAV wing to the LOS DL ground antenna. Also, the antenna gain is improved by the blockage reduction. The antenna gain is further improved by using the bent monopole antenna. The optimum solution of UHF antenna placement and shape on UAV is to mount the bent monopole antenna under the ventral fin.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.464-473
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• 2022

In this paper, about a lightweight design that satisfies the performance of UHF-GPS Antenna used in autonomous underwater vehicle is proposed. Structural analysis, watertight external pressure test and non-destructive testing used in the design process are decided in consideration of structural safety for operating external forces in the underwater environment. First, the material of radome is selected for the performance of the UHF-GPS Antenna for communication with the carrier on the underwater operation in consideration of the 20 bar pressure generated. And the material of radome as PA-GF is selected by conducting electromagnetic field analysis and structural analysis and by considering high strength, rigidity and high dielectric constant. Electromagnetic field analysis and structural analysis by the thickness of radome are additionally performed in order to satisfy the required weight of UHF-GPS antenna. After selecting the final model, its structural safety is verified through watertight external pressure test and non-destructive testing.