• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.3
• /
• pp.43-51
• /
• 2020

In this paper, the design of 64 array antennas applied to RWP (Radar Wind Profiler) was described. The design point of the antenna is to ensure isolation between each element and to match the vertical / horizontal radiation pattern. To this end, a single element of the array antenna was proposed as a Bend dipole type, and through simulation, When sequentially sending 5 beams including vertical, the east/west/south/north direction was ±20°, and it was confirmed that no Grating Lobe occurred when steering the beam. The 64 array antenna proposed in this paper was designed with performance equal to or higher than that of overseas products, and was confirmed to be applicable to RWP.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.7
• /
• pp.712-720
• /
• 2003

In this paper, a multi-layered metallic disk array structure(MDAS) excited by cross-dipole elements was proposed for efficiently shaping of flat-topped element patterns(FTEP) with circular polarization. The MDAS excited by cross-dipole elements has advantages to decrease in volume and weight of an overall array antenna and so, it is appropriate for the FTEP applications of a ralativlely low frequency band. In order to verify the effectness of this structure, the MDAS breadboard operated at X-band(7.9 ∼ 8.4 GHz) was fabricated, and its design parameters were experimentally optimized on the basis of the previous design experience. The experimental results were shown that the MDAS could shape good FTEPs of ${\pm}$20$^{\circ}$beam width at least within a 6.1 % frequency band.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.48 no.8
• /
• pp.400-407
• /
• 1999

This paper treated the design, manufacture and the performance characteristics under each mode of high speed motor/generator for an electro-mechanical battery(EMB). This machine is employed as an integral part of a flywheel energy storage system(FESS), i.e., a modular flywheel system to be used as a device for storing electrical or mechanical energy. In this machine, the magnetic field system is constructed by using special magnet array, dipole Halbach array with 16 permanent magnet segments and the armature is composed of a plastic bobbin and multi-phase windings with Litz wire. The magnet array produces a highly uniform dipole field without back iron. The motor/generator is 3-phase machine in which the dipole Halbach array surrounding the winding is rotating. Since there are no iron laminations, this field system offers some unique advantages for the simplicity of the design and the theoretical prediction of characteristics of a high speed electric machine. This paper describes the results obtained when EMB system was tested in the laboratory.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.30 no.3
• /
• pp.202-208
• /
• 2019

In this study, an active element pattern (AEP) of a printed dipole was analyzed in 1D and 2D arrays. First, an AEP of the printed dipole was obtained using the simulation in the 2D infinite array. The scan blindness in the 2D array occurred in the E-plane direction at around ${\pm}36^{\circ}$; however, it was barely observed in the 1D array. To analyze the cause of the scan blindness in the 2D array, the dispersion properties of a unit cell was obtained and compared with the scan blindness by frequency change. The difference between the scan blindness of the 1D and 2D arrays was clarified using the comparison of the Q value in the unit cell in the 1D and 2D arrays. Then, the coupling of the electric field in the E-plane direction was observed when nine elements were separated between the two ports in a linearly arranged dipole structure. Finally, the printed dipole array was fabricated, and an AEP was measured for the $11{\times}1$ and $11{\times}3$ sub arrays. The proposed theory was verified using these observations and by comparison with the simulation results.

• Journal of Environmental Impact Assessment
• /
• v.13 no.5
• /
• pp.223-230
• /
• 2004

The electrical resistivity prospecting method with dipole-dipole array were applied in order to survey 3-D structure characteristics of the Noen landfill site. For the electrical resistivity prospecting, 3 line of measurements were established parallel to the main boundary of the Noen landfill site and additional 2 lines were also established perpendicular to the existing 3 lines for the effective investigation of the landfill site. The results showed that the uppermost layer of the landfill site is believed to be stabilized generally based on the characteristics of electrical resistivity distribution. Lowest layer was partially polluted by the leachate.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.7
• /
• pp.1459-1467
• /
• 1997

The current on the thin planar structure as an element of the transversely fed electromagnetically coupled(EMC) microstrip dipole array antenna is obtained by using the integral forms of the finite difference time domain(FDTD) method. This method was applied to calculating the optimum current distribution (Doplh-Tchebyscheff distribution) of each dipole element on the feed line as a function of their offset positions for the narrow main beam width and the side beam level below -20 dB. The current on each dipole substitutes for the electric and magnetic current densities on the virtual surface of the FDTD calculation to express the far field intensity, the calculation time and the computer memeory can be reduced to about 80% and 1.3 Mbyte, respectively. The calculated radiation patterns are compared to the measured values and these are in good agreement.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.2
• /
• pp.244-250
• /
• 2012

The compact dipole antenna elements and array structure is proposed. The array structure is designed for applicator in regional hyperthermia treatment to enhance the uniformity of the heat distribution which makes the treatment effective and prevents overheating. The compact dipole is designed with branched dipole and matching network to have small size and symmetric shape. The temperature simulation with specific absorption rate(SAR) and bio-heat equation is performed to have heat distribution. The applicator is designed, fabricated, and measured with multi-channel thermometer in 30 and 60 minutes. The simulation and measurement results showed agreement and the simulation in body circumstance has proper temperature result for hyperthermia therapy.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.39 no.5
• /
• pp.251-258
• /
• 2002

In this paper, the dipole-fed planar array antenna applied Yagi-Uda antenna away theory to microstrip antenna is designed and fabricated at X-band. The design procedure of the dipole-fed planar array antenna with the wide bandwidth is presented to be easily practiced to a wireless communication system. The radiation pattern, return loss and bandwidth of the antenna are improved by the finite differential time domain(FDTD) numerical method. The propriety of analysis of planar dipole antenna is proved from the measured data. From the measured results, the antenna maximum gain is 4.9dBi at center frequency of 10GHz and frequency bandwidth is about 40%. Front-to-back ratio is 16dB, and half-power beam-width of E-plane and H-plane are 117$^{\circ}$and 156$^{\circ}$, respectively. When VSWR of antenna is less than 2, the measured results are agreed well with the theoretical values in the frequency range from 7.4GHz to 11.88GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.7 no.2
• /
• pp.105-116
• /
• 1996

The design and analysis of the transversely fed EMC(electromagnetically coupled) microstrip dipole have been accomplished by using the integral equation and MOM(method of moment)in frequency domain in order to find the current distribution of the dipole. In this study, we proposed the possibilities for design and analysis of EMC micro-strip dipole array antenna by means of calculating the current distribution of each dipole directly using the FDTD(finite difference time domain) method. In this case, we applied the formulation which is the finite difference expression of the Maxwell's integral equation. From the current distribution of each dipole, we calculated the far field electric component and showed that the calculation process and running time was reduced with respect to the method which calculates the radiation field with surface electric and magnetic current density.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.7
• /
• pp.661-668
• /
• 2011

Direction estimation of signal of interest has been an important issue in radar and communication system. Generally, DOA(Direction Of Arrival) methods have been researched in the field of signal processing with ideal array sensors. However, there are some problems in array antennas such as the input signal distortions in amplitude and phase, due to the mutual coupling between array elements. In this paper, we propose a new method of DOA estimation in the dipole array antenna by using the method of moment(MoM) to compensate the mutual coupling effects between array antenna elements. Also, the proposed method is applied to the estimation of azimuth(${\phi}$ ) and elevation(${\theta}$) angles using uniformly linear dipole array under noisy environments.