• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.30 no.6
• /
• pp.427-437
• /
• 2019

In January, 2019, the Ministry of Science and ICT announced the third edition of Master Plans for Radio Wave Promotion, effective from 2019 to 2023. The focus of this plan is to implement market based radio wave policy and horizontal regulatory framework. Although it appears to be past due, such change in the radio wave policy is not only fair and structured, but also unprecedented and ground breaking in legality. In order to successfully implement market based radio wave policy and horizontal regulatory framework, we must implement identical radio wave license based on license with consideration and time-limited usage. Through this, efficient distribution of finite radio wave resource may come to reality. Furthermore, there must be an effort to include life style regulation on license into radio wave act in the future.

• Journal of electromagnetic engineering and science
• /
• v.8 no.2
• /
• pp.64-69
• /
• 2008

In this paper, we have proposed the pattern adjustable base station antenna for WCDMA applications. The proposed antenna consists of an omni-antenna(sleeve monopole) and two movable reflectors. The two reflectors can be controlled by mechanically and used to adjust the horizontal pattern of the base station antenna. The antenna was designed, fabricated, and measured. The antenna covers the entire WCDMA band for VSWR<1.4. The measured antenna gain is more than 15 dBi over the operating frequency range. By changing the angle (a) and the distance (d) of the antenna, the pattern adjustment of the proposed base station antenna is found to be possible.

• Journal of the Korea Convergence Society
• /
• v.10 no.2
• /
• pp.7-11
• /
• 2019

Due to diversification and popularization of devices that use rapid transmission, there are many security issues related to radio waves. As the disturbance and interference of the radio wave can cause a direct inconvenience to a life, it is a very important issue. In this paper, as a means to prevent radio disturbance and interference, the projected image of the reference grid and the deformed grid is obtained by measuring the projected $moir{\acute{e}}$ using the white light source, projecting grid and the light source, and a $moir{\acute{e}}$ pattern is generated with an image processing algorithm by applying a phase diagram algorithm, and generated $moir{\acute{e}}$ pattern phase diagram creates a three-dimensional shape. By making an encrypted token using this measured face shape, the transmission of the information through token ring is determined in order to transmit the horizontal transmission having the dynamic security characteristics which includes authentication strength and caller information, etc. And by confirming the uniqueness of the token and by sending and receiving the horizontal transmission using java serialization and deserialization function, a problem solving method is suggested.

• Journal of electromagnetic engineering and science
• /
• v.10 no.3
• /
• pp.175-178
• /
• 2010

In this paper, a millimeter-wave multi-beam antenna is studied by rotating the antipodal linear tapered slot antenna(ALTSA) with respect to a center is successfully designed. In order to lowering the SLL and enhancing the isolation between the ALTSA elements, a row of metallic via is inserted between the ALTSAs. A 9 beams antenna is designed and experimented at Ka band. The measured and simulated results agree well with each other. The antenna can provide horizontal wide angle coverage up to ${\pm}62^{\circ}$. The gain of each beam can achieve about 12.5 dB. The mutual coupling between ports is all below 20 dB.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.2
• /
• pp.104-109
• /
• 2020

In this paper, we proposed a miniaturized folded inverted F antenna with ISM-band (center frequency : 447 MHz) for mounting in intelligent parking sensor. First, to mount the antenna in the intelligent parking sensor module (72 mm × 70 mm) with limited size, a folded inverted F antenna was designed at low frequency 447 MHz (wavelength λ : 670 mm) of the ISM-band. As a result, it resonates in the ISM band and obtains suitable characteristic with a -10 dB bandwidth of 13 MHz (2.9%). In addition, the H-plane pattern by the vertical and horizontal elements represents the omni-directional patterns from which the null point is removed, and the E-plane has directivity in a specific direction. Finally, it is suitable as and antenna for vehicle management in parking lots.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.9
• /
• pp.1030-1038
• /
• 2007

This paper presents the measurement results of strength of electromagnetic wave for GSM-900/GSM-1800 band which is used in Europe. The Giryong village and Sosan field are selected as candidate regions according to the measurement results in Gijang-gun, Busan. The vertical polarizations is about 12 dBm higher than horizontal polarization at two candidate places, and it is measured 25 dBm lower than urban. The maximum value of measured strength of vertical polarizations in the cellular/GSM-900 bands are -65 dBm at Giryong village and -69 dBm at Sosan field, respectively. The maximum value of measured results of PCS/GSM-1800 bands are -90.5 dBm at Giryong village and -85 dBm at Sosan field, respectively, We confirm that the receiving strength of electromagnetic wave are very weak below -65 dBm at two candidate places and the signals of GSM frequency bands not affect to conversional system, then it is considered as a suitable place for GSM mobile field test.

• Proceedings of KOSOMES biannual meeting
• /
• 2005.11a
• /
• pp.65-69
• /
• 2005

The theoretical propagation modes of radio waves in the area of Line of Sight(LOS) within Fresnel zone are searched for the available detection ranges in a Marine RFID (Radio Frequency Identification). The structural LOS model to Earth's curvature is proposed and, the calculation method of horizontal distance in a specific radio frequency is also considered in this work As studying results, it is found that the height of antenna to cover the detection ranges and the influences of detection ranges by weather environments can be analyse with the theoretical methods.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.2
• /
• pp.302-311
• /
• 1999

In this paper, in order to suggest an optimal polarization diversity composition method in indoor radio wave propagation environments, the variation of the cross polarization discrimination(XPD) was theoretically analyzed by a computer simulation and compared to the actual measured data. From the results, it can be seen that the cross polarization discrimination of the case, a circularly polarized antenna was used at the transmitting end as well as the vertical and horizontal polarized antenna branches were used at receiving end (CV-CH), is lower than that of the case, horizontal polarized antenna at the transmitting end as well as the horizontal and vertical polarized antenna branches at the receiving end(HH-HV), and that of the case, vertical polarized antenna at the transmitting end as well as the vertical and horizontal polarized antenna branches at the receiving end(VV-VH). In this paper, to get more effective CV-CH polarization diversity composition, the amount of cross polarization discrimination values at the signals received by horizontal polarized antenna is compensated and the polarization diversity effect through the cumulative probability distribution is estimated. From the evaluation results, it was found that the polarization diversity effect was better at the compensated case than at the uncompensated case. On the other hand, it can be known that the polarization diversity effect is getting better as the cross polarization discrimination values are getting lower, and also be known that the effect can be improved if a transmitting antenna is composed of the ellipse polarized antenna by adjusting the axial ratio of the circularly polarized antenna and, a receiving antenna is made up of the vertical and horizontal polarized antenna branches.

• Journal of electromagnetic engineering and science
• /
• v.5 no.2
• /
• pp.97-103
• /
• 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 The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.4
• /
• pp.61-70
• /
• 2008

This paper designed the antenna for collecting and servicing the traffic information that apply to freeway Traffic Management System, as using DSRC (Dedicated Short Range Communication). Active DSRC is the technology that is using 5.8GHz Radio Frequency to a mean Sequency and there are a lot of the case occurring a physical electric wave shadowing because of the traveling straight of a electric wave. In such inferior communication environment, it constructed the stabilized communication link that can do collecting and servicing the correct traffic information and designed the beam pattern considering the establishment position of the antenna that can apply to various road environments and a communication area. By considering the communication link environment, this paper designed and manufacture the mean frequency of 5.8GHz, the input loss of -17dB in 75MHz bandwidth, the Axial ratio of 1.5:1, and $2{\times}4$ array microstrip antenna which beam pattern have the characteristic of $55^{\circ}$ horizontal half power beam width and $26^{\circ}$elevation half power beam width and the minimum establishment height of the antenna was designed as 14m for avoiding electric wave shadowing on a physical condition between vehicles