• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 한국정보통신학회 2015년도 추계학술대회
• /
• pp.939-940
• /
• 2015

In this paper, a design method for a quasi-Yagi antenna (QYA) suitable for UHF band is studied. Due to the mutual coupling between a coplanar strip (CPS)-fed planar dipole and a conducting strip director placed close to the dipole, the dipole obtains broadband characteristics. A ground reflector improves gain in the lower frequency band, and the antenna size might be reduced by employing a bent reflector. The balun between the CPS line and the microstrip(MS) line is constructed by connecting the end of MS line and the CPS line through a shorting pin. In addition, a ring-type conductor connects the CPS line and reflector. The effects of various geometrical parameters and balun on the antenna characteristics are examined. An antenna, as an design example for the proposed antenna, is designed for the operation in the frequency band of 470-806 MHz for terrestrial DTV.

• Nuclear Engineering and Technology
• /
• 제34권3호
• /
• pp.211-217
• /
• 2002

A 1-MW vacuum feedthrough for the KSTAR ICRF antenna is fabricated and high power RF test is performed. It is designed to have two alumina $(Al_2O_3)$ ceramic cylinders and O-ring seal instead of a brazed seal for good mechanical and thermal strength, which is important in long pulse or steady state operation. For cooling of the ceramics, dry air is circulated in a space between the two cylinders and the outer conductor. Independent cooling water channels are installed to cool the inner conductor of the feedthrough. RF high voltage test is performed using two kinds of ceramics with the purities of 99.7% and 97%. Stable operation is possible with the RF voltage of 30 kVp at long pulse of 300 sec without any severe damage.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 한국통신학회 1986년도 추계학술발표회 논문집
• /
• pp.35-37
• /
• 1986

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• 제30권6호
• /
• pp.518-521
• /
• 2019

In this paper, an active antenna module operating in the 60 GHz band is designed and fabricated by combining a commercial transmitter chip and patch array antenna. The designed module is composed of an antenna PCB and a PCB with a transmitter chip. The frequency-control and bias-control signals are applied to the transmitter chip, using an Arduino kit. A baseband I/Q signal is also applied to the chip. A ring hybrid balun converts the output of the transmitter module to a single output, which is the output of the transmitter chip that outputs a differential output. The output is delivered to the $2{\times}4$ microstrip patch array antenna PCB as a micro-computer connector. The radiation pattern of the millimeter-wave signal of the final output is compared with the simulation results. The measured radiation patterns of the fabricated active antenna module confirm that the positions of the 3 dB beam width and null point agree well with the simulation results.

• Journal of electromagnetic engineering and science
• /
• 제10권4호
• /
• pp.303-308
• /
• 2010

This paper proposes a method for improving the isolation characteristic of multi-input multi-output (MIMO) antennas using a split ring resonator (SRR) array structure between the two radiating elements. The fabricated antenna satisfies the 10 dB return loss requirement in the Mobile-WiMAX frequency band from 3.4 GHz to 3.6 GHz. The isolation between the two radiating elements is improved by approximately 20 dB at the center frequency by inserting a SRR array structure. The measured peak gains of the two elements are 2.3 dBi and 2.4 dBi, respectively.

• Proceedings of the IEEK Conference
• /
• 대한전자공학회 2002년도 ITC-CSCC -2
• /
• pp.719-722
• /
• 2002

This paper reports the characteristics of a bidirectional antenna by using a planar array of a probe excited circular ring. The element of a bidirectional antenna is first designed to achieve the maximum directivity. The directivity can be further increased by arranging these elements to form the linear array. There are two types of linear array to be investigated i.e., on axis and off axis arrangement. On-axis linear array yields better directivity than off-axis linear array. Therefore, this orientation is further used to form the planar array. The radiation characteristics of this optimum planar array are rigorously reported. The proposed structure is very useful to extend the distance between the base station in PCT system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• 제22권11호
• /
• pp.1078-1091
• /
• 2011

In this paper, a triple band-notched UWB antennas using a spiral resonator and a complementary split ring resonator is proposed as two types. The band-rejection characteristic of the designed antenna is analyzed through the structure and equivalent circuit model of spiral resonator and CSRR. The measured results of first type antenna show that a VSWR less than 2 was satisfied with a resonant frequency in the range of 1.16~12 GHz and it can be obtained the band-stop performance at 3.3~3.85 GHz, 5.15~6.1 GHz, and 8.025~8.5 GHz. The measured results of second type antenna show that a VSWR less than 2 was satisfied with this antenna works from 1.79 to 12 GHz and it can be achieved the band-notched performance at 3.3~3.88 GHz, 5.12~5.94 GHz, and 8.025~8.51 GHz. Through the measured results, the designed antenna was satisfied UWB band except for triple notched bands.

• The Journal of the Korea institute of electronic communication sciences
• /
• 제10권10호
• /
• pp.1189-1196
• /
• 2015

In this paper, a microstrip-fed multiband monopole antenna for GPS(Global positioning system)/WiMAX(:Worldwide interoperability for microwave access)/WLAN(Wireless Local Area Networks) for applications was designed, fabricated and measured. The proposed antenna is based on a microstrip-fed structure, and composed of two rectangular double rings and L strips pair and then designed in order to get triple band characteristics. To obtain the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator(HFSS). The proposed antenna is made of $27.0{\times}54.0{\times}1.0mm3$ and is fabricated on the permittivity 4.4 FR-4 substrate. The experiment results shown that the proposed antenna obtained the -10 dB impedance bandwidth 300 MHz (1.325~1.625 GHz), 400 MHz (2.275~2.675 GHz), and 600 MHz (3.15~3.75 GHz) covering the GPS/WiMAX/WLAN bands. Also, the proposed antenna measured gain and radiation patterns characteristics for required operating bands.

• The Journal of the Korea institute of electronic communication sciences
• /
• 제12권1호
• /
• pp.25-30
• /
• 2017

In this paper, dual band patch antenna was designed using a CSRR structure with negative values permeability which inserted into the ground plane. We propose an antenna that can be used in dual band f1(1.53GHz) and f2(1.63GHz) for satellite communications by using the CSRR placed on the backside of feeding line, which is a negative shape of SRR. The proposed antenna can be arrayed using microstrip line and can be made smaller than conventional patch antenna. The fabricated antenna has the input reflection coefficient of -12.5dB and -14.5dB at f1 and f2, and the gain of 2dB and -0.8dB, respectively. and it was confirmed that the performance was sufficient in the dual-band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• 제26권4호
• /
• pp.365-373
• /
• 2015

In this paper, a planar antenna with monopole-like radiation pattern for on-body communications is proposed. The proposed antenna consists of three split-rings(SR) to generate a monopole-like radiation characteristic. To account for the on-body application, the proposed antenna is designed to have a low-profile. The antenna has an overall dimensions of $0.29{\lambda}_0{\times}0.29{\lambda}_0{\times}0.008{\lambda}_0$ at 5.8 GHz industrial, scientific, and medical(ISM) band(5.725~5.875 GHz). To verify the body effect, a two-thirds muscle equivalent semi solid phantom is fabricated and used to measure the antenna performance. The 10-dB return loss bandwidth is 280 MHz(5.68~5.96 GHz) and the measured peak gain is 1.91 dBi.