• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.50-57
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• 2001

This paper describes a design for the circularly polarized microstrip EMC cross dipole array antenna with the wide bandwidth. To realize the characteristics of wide bandwidth and circular polarization, the electromagnetic-coupled cross dipole element is proposed. The optimum design parameters of a circularly polarized EMC cross dipole element are calculated by the FDTD and the Ensemble. To obtain the uniform aperture illumination of electric field in an array, offset technique that the cross dipole elements are alternatively arranged on center of the microstrip feed line is adopted. In 20-element array design, the calculated axial ratio and gain are about 0.1dB and 9.9 dBi at 12 GHz, respectively, The frequency characteristics of a fabricated 20-element array antenna are measured. The calculated results agree well with the measured ones.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2199-2205
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• 2016

In this paper, a design method for a coplanar waveguide (CPW)-fed 2-element quasi-Yagi antenna (QYA) is studied. A balun between CPW and coplanar strip (CPS) which feeds a planar dipole is implemented by connecting the one end of ground strips in a CPW to a signal strip. The antenna size is reduced by bent strip dipole and reflector, and an integrated balun. The proposed antenna was designed for the operation in a UHF radio frequency identification (RFID) band of 902-928 MHz, and the effects of various parameters such as dipole length, reflector length, distance between dipole and reflector, feed position were examined. The antenna with a size of $90mm{\times}80mm$ was fabricated on an FR4 substrate, and the experiment results reveal a frequency band of 885-942 MHz for a voltage standing wave ratio < 2, a gain > 4.3 dBi, and a front-to-back ratio > 7 dB over the frequency band for the UHF RFID.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.6
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• pp.595-601
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• 2013

This paper presents an optimized design of a millimeter-wave on-chip dipole antenna using CMOS process. The serious flaw of the antenna using CMOS process is low radiation efficiency because of high permittivity and conductivity. To overcome the weakness, we need to widen radiation area in air and optimize distance between an antenna and a reflector. The radiation efficiency and bandwidth of the designed antenna are respectively 16.5 % and 22.3 % at 80 GHz. Systematic methods are attempt to analyze an effect on the antenna radiation efficiency. To widen radiation area in air, substrate cut angle and distance between the antenna and chip edge are adjusted. In addition, to optimize distance between an antenna and reflector, substrate thickness and distance between the antenna and a circuit ground plane are adjusted.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.45-52
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• 2009

In this paper, a new rectenna is presented for the wireless transmission of microwave power using dipole antenna (Quasi Yagi effect) and rectifier of CPS resonator structure. The dipole antenna with CPW feedline has high peak gain than a general dipole antenna. A ground plane of CPW is used to reflect a dipole as a Yagi antenna. Therefore, the new rectenna receives the RF power better than the one using general dipole. A RF-to-DC conversion efficiency of 61 % using a 1.4 $k{\Omega}$ load resistor is obtained at 5.8 GHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1296-1302
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• 2012

In this research, optimization of a dual-band dipole array was performed using genetic algorithm. A non-uniform, aperture-shared linear array was configured with dipoles which resonate at 4 GHz and 9.5 GHz. The excited current distributions on dipoles were computed considering mutual coupling between dipole elements. The current distributions were also computed using method of moment (MoM). The optimization using genetic algorithm was performed to obtain the low sidelobe levels in two operating frequency band. The PSLs of the optimized array for 4 GHz and 9.5 GHz are -15.7 dB and -17 dB, respectively. Comparison between computed and simulated results are also discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.8
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• pp.785-792
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• 1991

We designed the hal wavelength dipole antennal which can be used for he determination of the suitability of an antenna test site and considered the characteristic of antenna factors by using the moment methods. Antennal factors remain almost constant with negligible variations for the variations of $\pm$1 mm antenna dimention-radius and length. comparisons are mae between measured values and calculated results for the input impedance.

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

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.533-538
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• 2018

For WLAN dual-band operation, a modified Yagi dipole antenna is presented. The modified dipole antenna consists of a dipole antenna with open sleeves and parasitic elements. The parasitic elements are used for the practical application of the radiation patterns and high-gain operation at the WLAN dual band. The experimental results showed that the achieved impedance bandwidths were 320 MHz (2.4 to 2.72 GHz) and 640 MHz (5.04 to 5.68 GHz), respectively. The measured maximum gain at the two WLAN bands was 7.74 dBi and 6.93 dBi, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1027-1035
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• 2016

In this paper, the method to miniaturize the radiating element of a VHF-band active electronically scanned array is proposed. The length of the proposed dipole having trapezoidal shape structure is miniaturized using meander line while the performance degradation is minimized. The grid reflector is used to improve the antenna directivity and insensitivity due to the outer environment. In addition, the antenna is designed to take into account for array application. The fabricated antenna has a 9.1 % fractional bandwidth for the voltage standing wave ratio(VSWR) 2:1 and the maximum gain of 4.24 dBi. The front-to-back ratio(FBR) is larger than 15 dB.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.63-64
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• 2017

In this paper, we studied a design method for a coplanar waveguide-fed compact quasi-Yagi antenna for a dual band of the UHF RFID (915 MHz) and GPS (1.575 GHz). The proposed antenna is composed of three elements of a dipole, a reflector, and a director. To reduce its size, the ends of both the dipole and reflector are bent, the director is placed near to the dipole, and a balun is incorporated in the antenna. From some simulations, the proposed antenna using an FR4 substrate with 0.8 mm thickness was designed for the operations in the UHF RFID and GPS systems, and the antenna characteristics such as reflection coefficient, gain, and radiation patterns were examined.