• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.1 s.116
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• pp.82-89
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• 2007

This paper presents a coplanar waveguide fed L-planar type monopole antenna which covers ultra wideband(UWB) region of 3.1 GHz to 10.6 GHz. The proposed UWB L-planar type monopole antenna is designed and implemented on the organic substrates( ${\varepsilon}_{r}=3.38,\;@10\;GHz$). The radiation elements, feed line, and ground planes of the antenna are printed on the same conductive layer of the substrates. The bandwidth of the proposed antenna is measured in the range of 3.0 GHz to 11.0 GHz. The measured radiation patterns are symmetrical in E-plane and omni-directional in H-plane. Antenna gains ranges from 1.4 dBi to 4.6 dBi. The proposed UWB antenna shows that the structure is adequate for the design of RFIC.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.967-975
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• 2012

This paper presents a method to measure reflection coefficients of microwave devices or antennas based on time domain analysis with sampling oscilloscopes. The reflection coefficients were extracted by the Fourier transformation of echo pulses from devices with respect to the 20 GHz incident pulse signals. The three-error terms, which are commonly used for the correction of a microwave network, were determined using a 3.5 mm calibration kit. In addition, a modified error-correction model associated with a directional coupler for reflection coefficient measurements is introduced. The results were compared with those of measured with a commercial vector network analyzer.

• 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 The Korea Institute of Intelligent Transport Systems
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• v.19 no.1
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• pp.94-106
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• 2020

Recently, the radio navigation method utilizing the GPS(Global Positioning System) satellite information is widely used as the method to measure the position of objects. As GPS applications become wider and fields based on various positioning information emerge, new methods for achieving higher accuracy are required. In the case of autonomous vehicles, the INS(Inertial Navigation System) using the IMU(Inertial Measurement Unit), and the DR(Dead Reckoning) algorithm using the in-vehicle sensor, are used for the purpose of preventing degradation of accuracy of the GPS and to measure the position in the shadow area. However, these positioning methods have many elements of problems due not only to the existence of various shaded areas such as building areas that are continually enlarged, tunnels, underground parking lots and but also to the limitations of accumulation-based location estimation methods that increase in error over time. In this paper, an efficient positioning method in a large underground parking space using Fingerprint method is proposed by placing the AP(Access Points) and directional antennas in the form of four anchors using WLAN, a popular means of wireless communication, for positioning the vehicle in the GPS shadow area. The proposed method is proved to be able to produce unchanged positioning results even in an environment where parked vehicles are moved as time passes.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.449-455
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• 2018

For the size reduction, we propose a microstrip-fed monopole antenna with half X-slot in the radiation patch and cover WLAN dual band 2.4 GHz band (2.4 ~ 2.484 GHz) and 5 GHz band (5.15 ~ 5.825 GHz). The frequency characteristics such as impedance bandwidth and resonant frequencies were satisfied by optimizing the numerical values of various parameters, while the reflection loss in 5 GHz was improved by using defected ground structure (DGS). The proposed antenna is designed and fabricated on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of $24{\times}41mm^2$. The measured impedance bandwidths (${\mid}S_{11}{\mid}{\leq}-10dB$) of fabricated antenna are 450 MHz (2.27 ~ 2.72 GHz) in 2.4 GHz band and 1340 MHz (4.79 ~ 6.13 GHz) in 5 GHz band which sufficiently satisfied with the IEEE 802. 11n standard in dual band. In particular, radiation patterns which are stable as well as relatively omni-direction could be obtained, and the gain of antennas in each band was 1.31 and 1.98 dBi respectively.