• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1299-1305
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• 2002

Tx/Rx dual microstrip array antennas for satellite communications are designed, fabricated, and measured in this paper. They have a Right Handed Circular Polarization (RHCP) for Tx and Left Handed Circular Polarization (LHCP) for Rx. Two stacked patches are used for wideband characteristics and corner-truncated square patches are adopted for a circular polarization. To enhance bandwidth characteristics of a circular polarization, 2${\times}$1 sequential rotation mays are applied. From the measured results, 8${\times}$1 microstrip may antennas have a good agreement with those of the simulation. Therefore the array antennas are applicable to satellite communication antennas, active phased may antennas, and radiators in other antennas.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.131-137
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• 2023

In this paper, a phase comparison direction finding method of circular array composed of 8 antennas considering polarization characteristics is analyzed. A broadband cavity-backed patch antenna operating in 6 ~ 12 GHz is used, and the antennas are arranged in radial direction to receive various polarization signals. For the phase comparison, widely spaced elements are used to obtain precise DOA(Direction of Arrival), and narrowly spaced elements are used to resolve ambiguity. Two dimensional direction finding is performed for ±20° in both azimuth and elevation, and the DOA error is less than 0.5° and 1.6° near the boresight and the ±15° region, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.187-190
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• 2001

In this paper we designed a dual-frequency circular sector microstrip antenna fed microstrip line with orthogonal polarization. The operating frequencies and polarization characteristics of the proposed antenna is calculated by using a cavity model. The antenna operating at about 1.87 GHz and 2.42 GHz is fabricated and its S-parameters and radiation patterns are measured.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.769-777
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• 2010

In this paper, a switchable circularly polarized microstrip patch antenna using PIN diodes and corner slots on ground plane is proposed at 2.4 GHz. The proposed antenna has a square microstrip patch and ground plane that consists of two pair of slots and PIN diodes. The electrical lengths of the slots are adjusted by using the switching characteristic of the PIN diode, so the polarization of the proposed antenna can be switchable between linear, left-handed(LH) and right-handed(RH). By separating the ground plane for the DC bias, the size reduction effect is also obtained. When the proposed antenna is operated as linear polarization, the return loss and impedance bandwidth are 15 dB, 59 MHz, and when operated as LH and RH polarization, the minimum axial ratio and 3-dB axial ratio bandwidth are 1.17 dB, 1.67 dB, 28 MHz, and 32 MHz, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8A
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• pp.794-801
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• 2007

In this paper, in order to enhance the performance improvements of both BER and PAPR characteristic for the conventional OFDM system, both circularly polarized waves and carrier interferometry signals which shows the robustic fading reduction effect are applied to the system, and then the performance of the proposed system has been evaluated by computer simulation. From the analysis, it can be seen that the system BER performance can be improved by 2 or 3 dB. Furthermore, it can be also seen that the PAPR characteristic can be markedly reduced.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1213-1221
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• 2005

In this paper, dual-polarized antenna for UHF RFID reader has been described. Feeding network and antenna structure have been designed, such that both port isolation between transmitting and receiving port and cross-polarization be maximized, and overall antenna size be minimized as well. In addition, sequentially rotated feeding scheme has been adopted to secure axial ratio bandwidth in the circular polarization. Test results show 2.35 dBi antenna gain in 900 to 928 MHz frequency range and 150 MHz axial ratio bandwidth, respectively. And, the proposed antenna has a port isolation of -40 to -38 dB and a cross-polarization of -40 to -30 dB.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.1
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• pp.34-42
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• 2001

The new periodic array structure or frequency selective surface with polarizers characteristic is proposed. The present structure is constructed with two sheets or FSS material, spaced about one-eight wavelength apart, the dipole element orientations of the two sheets being almost perpendicular to each other. The methods of the spectral domain immittance and MoM are used to analyze electromagnetic scattering from this periodic array structure. To confirm the validity of the polrizer's functions or the new periodic array structure, frequency selective surfaces are fabricated, calculated values for the frequency response of the reflection and transmission loss are compared with measured values. Good correspondence has been observed between them. Good axial ratio has been also observed to be achieved in the proposed structure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1316-1324
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• 2009

In this paper, cross-aperture coupled microstrip circular polarization antenna is proposed for 5.8 GHz WLAN(Wireless Local Area Network). A single antenna consists of square patch and slots are located in series feed line with $\lambda_g$/4 phase different which make current direction maximum and minimum repeatedly to generate RHCP(Right Handed Circularly Polarization). We are proposed new structure that removed the section which intersected at a right angle and were composed to four separated slots. The proposed cross slots reduce back lobe of radiation pattern and improve antenna gain. Impedance bandwidth of the manufactured $2\times2$ array antenna is from 5.67 to 5.95 GHz and the maximum radiation gain is 10.59 dBi.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.569-571
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• 2007

In this paper, hem antenna composed of rectangular hern, circular polarizer and straight-type mode convertor is designed and fabricated. The circular polarizer is designed as a dielectric type having broadband characteristic, and it is inserted into the rectangular hem with $45^{\circ}$ inclination. The straight-type mode convertor has a terrace-type structure in order to convert the TEM mode signal of coaxial cable to the TE mode of rectangular waveguide, and this structure minimizes conversion loss. Fabricated hem antenna operates at $30.085\sim30.885GHz$ and has VSWR < 1.5, Axial ratio < 1.0dB and antenna gain of $6.7\sim7.0dBi$ in the band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.4
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• pp.628-635
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• 1999

At center frequency of 11.85 GHz, wideband left-handed circularly polarized microstrip array antenna is designed with the method of sequential ratation based on $2\times2$ radiation elements($0^{\circ}$, $45^{\circ}$, $90^{\circ}$, $135^{\circ}$ phase delay). Its return loss, axial ratio bandwidth, radration pattern, and gain are compared with those adopting sequential rotation based on $1\times2$ radiation elements($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, $270^{\circ}$phase delay). The $8\times8$ array is manufactured and measured. The results show that 10 dB return loss bandwidth is 10.51~12.74GHz(18.82%) which is 1.57 times wider than the case using $1\times2$ sequential rotation method, 3 dB axial ratio bandwidth is 11.43~12.5 GHz(9.03%) which is 1.25 times as wide as that using $1\times2$ sequential rotation method and the antennal gain is 25.4 dB. The results of mesurements are almost similar to those of simulation.