• ETRI Journal
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• v.34 no.5
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• pp.767-770
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• 2012

This letter presents a novel compact circularly polarized patch antenna for Global Positioning System/Global Navigation Satellite System (GPS/GLONASS) applications. The proposed antenna is composed of a simple square radiating patch fed by a capacitive dual-feeder to increase the impedance bandwidth and a lumped element hybrid coupler to achieve the broadband characteristic of the axial ratio (AR). The realized antenna dimensions are $28mm{\times}28mm{\times}4mm$, which is the most compact size among the dual-band GPS/GLONASS antennas reported to date. The measured results demonstrate that the proposed antenna has a gain of 2.5 dBi to 4.2 dBi and an AR of 0.41 dB to 1.51 dB over the GPS/GLONASS L1 band (1.575 GHz to 1.61 GHz).

• ETRI Journal
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• v.41 no.3
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• pp.289-297
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• 2019

In this paper, a wideband, circularly polarized patch antenna is proposed that leverages the unidirectional resonant modes of a circular patch mounted on top of a grounded dielectric-ferrite substrate. The proposed antenna is fed via the proximity coupling method and several parasitically coupled patches are placed on a dielectric superstrate to enhance the impedance bandwidth of the antenna. The resonant modes of the structure rotate only in the clockwise or counter clockwise directions. In the frequency range where the effective permeability of the ferrite layer is negative, the resonance frequencies of these modes differ significantly, which produces a large axial ratio (AR) bandwidth. For the proposed antenna, the numerical results show the 10 dB impedance bandwidth to be around 44% and the 3 dB axial ratio bandwidth to be higher than 64%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.411-417
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• 2008

This paper presents the miniaturization of circularly polarized microstrip patch antenna for UHF-band RFID portable reader. The proposed antenna has a group of four I-slots on a conventional corner-truncated square microstrip patch and it is shown that the antenna size is reduced compared to the antenna without I-slots. A 76 mm by 76 mm small antenna with four I-slots is fabricated with 6.4 mm thick FR4 substrate and its 10 dB return loss bandwidth, the gain and the axial ratio are measured to be $938{\sim}975\;MHz$, $-0.88{\sim}-2\;dBi$, and $3.27{\sim}13.21\;dB$ within the 10 dB return loss bandwidth, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.806-812
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• 2009

In this paper, the omnidirectional circularly polarized(CP) antenna using arc-shaped mushroom structure with curved branch is proposed. To obtain a vertical polarization and an omnidirectional radiation pattern, the CP antenna uses zeroth-order resonance(ZOR) mode of composite right and left handed(CRLH) transmission line. The horizontal polarization is achieved by the curved branches. Also, the spacing between curved branch and arc-shaped mushroom structure gives the $90^{\circ}$ phase difference between vortical and horizontal polarization. The proposed antenna, therefore, has an omnidirectional CP radiation pattern In the azimuthal plane. The electrical size of the proposed antenna is reduced by 38%, compared with that of the previously presented omnidirectional CP antenna. In addition, the CP antenna is simply designed without $90^{\circ}$ phase shifter and dual feed line. The proposed antenna uses a Bazooka balun for good impedance matching and radiation pattern. To improve 3 dB axial ratio in XY plane, the designed antenna is optimized. After optimization, the measured 3 dB axial ratio in XY plane is observed in $86{\sim}282^{\circ}$.

• 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 Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3880-3884
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• 2010

In this paper, circularly polarized micro-strip GPS antenna has been designed and fabricated. In order to improve of frequency properties, patch size, corner truncated size and feed positions were simulated using HFSS simulation program. Micro-strip GPS antenna was fabricated on the FR4 substrate of dielectric constant 4.4. The fabricated GPS antenna has that center frequency is 1.575GHz and insertion loss is -34.50dB.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.41-46
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• 2022

This study is a Ku-band array antenna for the manufacture of low-orbit satellite communication terminals, designed to have miniaturization, high gain, and wide beam width. The transmission of low-orbit satellite communication has a right-rotating circularly polarized wave, and the reception has a left-rotating circularly polarized wave. The 4×8 array antenna was separated for transmission and reception, and it was combined with the RF circuit part of the transmitter and receiver, and was terminated in the form of a waveguide for RF signal impedance matching in the form of a transition from the microstrip line to the waveguide. The 30° beam width of the receiver maximum gain of 19 dBi and the 29° beam width of the transmitter maximum gain of 18 dBi are shown. Through this antenna configuration, the system was configured to suit the low-orbit satellite transmission/reception characteristics.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.364-368
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• 2000

In this paper, we present the design and fabrication of a new circularly polarized circular patch antenna. The antenna is realized using a plastic foam sheet, a Teflon substrate and a metal-coated film. The radiating element is a circular patch proximity-fed by a wide microstrip line. Two thins slots are introduced on the circular patch to obtain a circular polarized radiation. The antenna is optimized using a commercial software. The antenna has 18% impedance bandwidth, 4% axial-ratio band width and 9.12dBi gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.302-311
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• 1999

In this paper, in order to suggest an optimal polarization diversity composition method in indoor radio wave propagation environments, the variation of the cross polarization discrimination(XPD) was theoretically analyzed by a computer simulation and compared to the actual measured data. From the results, it can be seen that the cross polarization discrimination of the case, a circularly polarized antenna was used at the transmitting end as well as the vertical and horizontal polarized antenna branches were used at receiving end (CV-CH), is lower than that of the case, horizontal polarized antenna at the transmitting end as well as the horizontal and vertical polarized antenna branches at the receiving end(HH-HV), and that of the case, vertical polarized antenna at the transmitting end as well as the vertical and horizontal polarized antenna branches at the receiving end(VV-VH). In this paper, to get more effective CV-CH polarization diversity composition, the amount of cross polarization discrimination values at the signals received by horizontal polarized antenna is compensated and the polarization diversity effect through the cumulative probability distribution is estimated. From the evaluation results, it was found that the polarization diversity effect was better at the compensated case than at the uncompensated case. On the other hand, it can be known that the polarization diversity effect is getting better as the cross polarization discrimination values are getting lower, and also be known that the effect can be improved if a transmitting antenna is composed of the ellipse polarized antenna by adjusting the axial ratio of the circularly polarized antenna and, a receiving antenna is made up of the vertical and horizontal polarized antenna branches.

• Journal of the Korea Convergence Society
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• v.6 no.1
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• pp.109-114
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• 2015

A circularly polarized small UHF RFID reader antenna is presented. The antenna is composed of four elements and printed on the plastic substrate(${\varepsilon}_r=2.2$, t=5mm). Each element is fed by a probe which is sequentially connected to the feed line. The feed line is manufactured on the FR-4 substrate(t=1.0mm, ${\varepsilon}_r=4.7$). The simulation results shows that the antenna can be achieved a return loss of 12dB, gain of 3.46dBic over the UHF band of 902-928MHz. According to our simulation results, two prototype antennas are manufactured and measured. The obtained antennas operate in UHF RFID bands and can be adapted for various portable applications. In addition, a parametric study is conducted to facilitate the design and optimization processes.