• Journal of IKEEE
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• v.15 no.4
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• pp.299-304
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• 2011

In this paper, the circular polarized horn antenna composed of circular polarizer and impedance transformer is designed, and fabricated. For the circular polarizer, two types of the polarizer are designed and the electrical performance of them is compared; rectangular waveguide polarizer with $45^{\circ}$-inclined dielectric slab and oval shaped one. Straight type mode converter has a stepped impedance structure and plays a role of converting waveguide TE mode into coaxial TEM mode, and the proposed antenna is designed to directly connect with active components using the feed-through in the input port of the mode converter. Fabricated antenna has the wideband performance, VSWR<1.5 and Axial ratio < 1.0dB, ranging from 30.085 to 30.885 GHz, and the antenna gain is 6.7~7.0 dBi.

• Journal of IKEEE
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• v.17 no.2
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• pp.140-144
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• 2013

This paper presents the novel design of circular polarized Ka-band horn array antenna. The element antenna of the arrya is composed of two parts, microstrip patch and square horn, and the microstrip patch is fed by corner truncated microstrip patch for circular polarization. The patch antenna has the role of a feeder and polarizer of the horn, thus the whole size of the horn antennae can be considerably reduced. The $1{\times}8$ horn array was designed and fabricated by the spacing of $0.9{\lambda}_0$ among the element horn. The element horn has typical gain of 8dBi and axial-ratio bandwidth of 4.9% at 3dB, and the minimum gain and axial-ratio bandwithd of the array is 14dBi and 8.2%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.32-38
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• 2014

In this paper, we design a secant pattern antenna combined with a septum circular polarizer to be used in the satellite data communications. To generate a radiation pattern with secant type, Fourier relationship between current distribution and space factor is applied and the circular symmetric structure of the aperture simplifies the design. The optimization process is performed by combining the radiator with the septum circular polarizer, and it is confirmed that the designed radiation pattern, axial ratio, and return loss characteristics satisfies the required performance of the antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.113-121
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• 2013

In this paper, quadruple polarized antenna system with a reconfigurable feeding network is presented. The proposed antenna system consists of the reconfigurable feeding network for fourth polarization such as vertical/horizontal linear polarization and right-handed/left-handed circular polarizations or 45 degree tilted vertical/horizontal linear polarization and patch antenna to receive the signals with various polarizations. In order to receive a signal in any direction, the proposed antenna is designed by electrical switches for reconfigurable polarization. The insertion loss of the designed feeding network in the proposed antenna system is approximately 1.2 dB. The measured 3 dB axial bandwidth and gain of the proposed antenna are about 2 % and 4 dBi(c).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.533-540
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• 1999

In this paper, a microstrip antenna is designed using a rectangular patch. To find characteristics of the antenna, computer simulations of the rectangular single microstrip patch antenna are performed with changing width and feed line. And we found characteristics of RHCP using axial ratio. Through the results, we found that the Finite Difference Time Domain(FDTD) method is an effective method for designing microstrip patch antenna. According to simulation the resonant point has been found it in the frequency received from GPS satellite. And these results were in relatively good accordance with the measured values.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1034-1041
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• 2012

In this paper, a compact circularly polarized metamaterial patch antenna using the -1 mode that is induced by the composit right-left handed(CRLH) transmission line is proposed. Basically, since the -1 mode is the same properties with the +1 mode of the conventional patch antenna, the circular polarization(CP) is realized. If two orthogonal -1 modes are excited with $90^{\circ}$ phase difference, the CP property can be obtained. In order to obtain two orthogonal modes and $90^{\circ}$ phase difference, 4 mushroom structures having the shape of triangle are employed and the inter-digital gaps are optimized, respectively. The fabricated antenna is based on RT/duroid5880 substrate and the total area of the 4 mushrooms is $0.161{\lambda}_0{\times}0.161{\lambda}_0$. It is confirmed that the center frequency of the proposed antenna is measured as 2.845 GHz and it operates from 2.830 GHz to 2.850 GHz. In addition, the antenna maintains the CP property from 2.842 GHz to 2.847 GHz at the peak gain and the measured radiation efficiency is 46 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.144-150
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• 2012

In this paper, circularly polarization patch array antenna of RSE(Road-side Equipment) base station for DSRC(Dedicated Short Range Communication) of ITS(Intelligent Transport System) is proposed. The antenna of RSE base station for DSRC is designed to operate circularly polarization to receive reflected signal from multiplex path effectively. The proposed antenna consisted of microstrip patch and feed line, the slit is inserted in the proximity of the slot of feed structure to generate circularly polarization. The $2{\times}2$ array structure is designed to satisfying gain that DSRC RSE base station antenna required. Measured impedance bandwidth and axial-ratio bandwidth are satisfied by all DSRC band of 5.795~5.855 GHz. Vertical and horizontal HPBW of the proposed antenna are both about 43 degrees, it showed gain characteristic of about 11.21 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1177-1183
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• 2010

In this paper, design of a microstrip-fed, Spidron fractal-shaped slot antenna with circular polarization is represented. The ground plane of the designed antenna has a slot that comprises seven right-angled triangle next to each other in a low. A reflector is placed at the bottom on microstrip feeding line to enhance the antenna gain. The optimized design was conducted by varying a length of the first right-angled triangle, location of feeding line, space between a substrate and a reflector. The proposed antenna was fabricated on a Taconic-RF35 substrate. The entire dimension of the fabricated antenna is $40{\times}40{\times}18.6mm^3$ and the reflector is 18.6 mm away from the ground plane. The measured gain of the fabricated antenna is 6.7 dBi at 4.3 GHz. The measured bandwidths of -10 dB reflection and 3 dB axial ratio are 41 % and 7.4 %, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.562-571
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• 2008

In this paper, we propose a novel structure of a spiral antenna with a CP characteristic for RFID reader in UHF band. Since the proposed antenna can be built by printing on a FR-4 substrate, it is appropriate for low-cost mass-production. The antenna is designed to operate in UHF band of $860{\sim}960$ MHz. The CP bandwidth is Increased enough to cover an overall UHF RFID band by using a spiral structure for the antenna arm. The matching bandwidth is broadened by using a quarter-wave transformer between the fred and the antenna body. The proposed antenna has advantages of its easy gain and pattern control with a small antenna size. The measured antenna performance shows the matching bandwidth of 13%, the CP bandwidth of 23%, and the gain of 6.5 dBi. This verifies that the proposed antenna is appropriate for RFID antennas in UHF band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.842-849
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• 2010

This paper deals with a TT&C circularly polarized turnstile antenna for LEO satellites. The turnstile antenna consists of radiator for radiating power to free-space and power divider for generating circularly polarized wave. we presents a radiator to tolerate in space environments and a power divider to provide flat phase difference at wide bandwidth. The bandwidth of the proposed antenna covers the frequency bands of up- and down-link. The antenna shows wide beamwidth and enhanced axial ratio for unfavorable space environments.