• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.234-237
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• 2002

A microstrip patch antenna with circular polarization based on the Sierpinski fractal is composed of 3 equilaterial triangular Polarization by sequentially rotation techniques. The characteristics of a $1\times3$ antenna array from Sierpinski geometry an investigated, i.e. port isolation and AR(axial Ratio).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.1
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• pp.75-83
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• 1989

In this paper, applying the REC model which characterizes the coupling between the radiating edges to two coupled rectangular microstrip patch antenna, we obtain scattering parameters $\mid$ $S_{11}$ $\mid$ and $\mid$ $S_{12}$ $\mid$for the various coupling separations, Se=0.5mm, 1.0mm, 1.5mm, and 2.0mm, The calculated values are compared with the measured values. For the rectangular microstrip patch antenna with a parasitic element which is gap-coupled to the radiating edges of the rectangular patch, calculated return losses using the REC model are compared with measrued values. Here, the each microstrip antenna is fed by a 50 microstrip line. The purpose of the paper is to compare a 50$\Omega$ microstrip line fed case with a coaxial fed case treated in Ref.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.440-443
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• 2007

In this paper, microstrip antenna is designed for industrial-scientific-medical(ISM)band of S-Band. We proposed that radiation element of antenna, which is rectangle patch shape. The feeding structure used L-shaped structure. Center frequency and -l0dB bandwidth are investigated by change of length and width in patch plane. And maximum gain, front to back ratio and 3dB beam width is presented by simulation radiation pattern of antenna in frequency ISM Band. The center frequency is 2.45GHz, band width is $2.314{\sim}2.577GHz$ with 263MHz(11%). And the antenna maximum gain is 9.3dBi, 3dB beam width E-plane is $52.5^{\circ}$, H-plane is $64.7^{\circ}$.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.2
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• pp.24-29
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• 2015

In this paper, a microstrip antenna with isoflux radiation patterns is presented for Low Earth Orbit(LEO) medium-sized satellites. Because of making isoflux patterns, the ground of proposed antenna under the patch was transform into a trapezoid for adjusting fringing field between the patch and ground. Next, the cavity walls were located at end of the ground for reducing back radiation. The proposed antenna was designed to receive S-band uplink(2.025 ~ 2.110 GHz) and the dimensions of the designed antenna with the ground are $160mm{\times}160mm{\times}40mm$ ($1.1{\lambda}{\times}1.1{\lambda}{\times}0.3{\lambda}$, ${\lambda}$ is the free-space wavelength at 2.068 GHz). Measured -10 dB bandwidth was 90 MHz(4.4 %) and it covers the required system bandwidth. Also, measured 3 dB axial ratio was 18 MHz(0.9 %). On the other hand, measured radiation patterns were isoflux patterns and its measured gain was 5.31 dBi at E-plane $46^{\circ}$ in the y-axis pol.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.4
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• pp.219-225
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• 2000

In this paper, we report the experimental setup and characterization of experimental results for the HTS antenna. The constructions of experimental setup must be fabricated, cautiously. We constructed the cryostat made of 3 stages which consists of radome, vacuum stage and helium refrigerator for the HTS antenna. The HTS antenna was mounted to cryostat and various characteristics were measured at room temperature and liquid nitrogen temperature, 77 K. Also the results for the HTS antenna and the gold antenna were compared in terms of reflection coefficient, E-plane and H-plane radiation pattern, input impedance, SWR and efficiency. It appeared that the HTS antenna was superior to gold counterpart over the all characteristics.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.213-217
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• 2012

In this paper, we design dual-band microstrip antenna for IEEE 802.16e mobile WiMAX standard IEEE 802.11 WLAN band at the same time. To solve interference at the desired operating frequency band, impedance matching is improved and simple production method showed the characteristics of the omni-directional and compact size. The proposed structure is considered to bring the effect of the installation costs, and show the antenna for dual-band communication.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.4
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• pp.27-37
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• 2001

The design, fabrication, and an experimental implementation of the strip patch antenna coupled with a H-shaped aperture arc presented in this paper. The proposed antenna has the wide bandwidth, high gain, and low cross-polarization levels. We measured the VSWR, smith chart impedance characteristic, co/cross polarization pattern, gain, and so on. The measured bandwidth of this antenna is 47.1 %. To reduce the back lobe and increase the gain, when the reflector is used, cross polarization level is below -18.2dB at E-plane and below 25.7 dB at H -plane. The maximum gain at 2.05 GHz is also 10.4 dBi and the 3 dB gain bandwidth with center frequency at 2.17 GHz is 24 %, which is the wide bandwidth. This antenna can find applications in mobile communication, wireless LAN, RF communication system, and so on.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.117-128
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• 2018

In this paper, compact linear dual polarized series-fed $1{\times}2$ linear and $2{\times}2$ planar arrays antennas for airborne SAR applications are proposed. The proposed antenna design consists of a square radiating patch that is placed on top of the substrate, a quarter wave transformer and $50-{\Omega}$ matched transformer. Matching between a radiating patch and the $50-{\Omega}$ microstrip line is accomplished through a direct coupled-feed technique with the help of an impedance inverter (${\lambda}/4$ impedance transformer) placed at both horizontal and vertical planes, in the case of the $2{\times}2$ planar array. The overall size for the prototype-1 and prototype-2 fabricated antennas are $1.9305{\times}0.9652{\times}0.05106{{\lambda}_0}^3$ and $1.9305{\times}1.9305{\times}0.05106{{\lambda}_0}^3$, respectively. The fabricated structure has been tested, and the experimental results are similar to the simulated ones. The CST MWS simulated and vector network analyzer measured reflection coefficient ($S_{11}$) results were compared, and they indicate that the proposed antenna prototype-1 yields the impedance bandwidth >140 MHz (9.56-9.72 GHz) defined by $S_{11}$<-10 dB with 1.43%, and $S_{21}$<-25 dB in the case of prototype-2 (9.58-9.74 GHz, $S_{11}$< -10 dB) >140 MHz for all the individual ports. The surface currents and the E- and H-field distributions were studied for a better understanding of the polarization mechanism. The measured results of the proposed dual polarized antenna were in accordance with the simulated analysis and showed good performance of the S-parameters and radiation patterns (co-pol and cross-pol), gain, efficiency, front-to-back ratio, half-power beam width) at the resonant frequency. With these features and its compact size, the proposed antenna will be suitable for X-band airborne synthetic aperture radar applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.306-313
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• 2012

In order to enhance the isolation level between two dual-band E-slot microstrip patch antennas, EBG structure which operates in UMTS Tx(1.92~1.98 GHz) and Rx(2.11~2.17 GHz) band is proposed. The proposed EBG structure made with a periodic array of two different size EBG unit cells which has a modified mushroom-type for isolation improvement between two antennas. They do not share a common ground plane of the microstrip patch antenna. Overall size of the fabricated antenna is $210.5mm{\times}117mm$. The two different EBG unit cell sizes are $15.6mm{\times}4mm$ and $17.4mm{\times}4mm$, respectively. It was etched on the FR-4 substrate(thickness=3.93 mm, ${\varepsilon}_r$=4.6). The experiment results show that the isolation level between antennas in Tx/Rx band were improved by about 9 dB and 12 dB, respectively, through the use of the proposed EBG structure.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.3
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• pp.62-72
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• 2022

In this study, a miniaturized GPS band(L₁ : 1.575 GHz) antenna that can be mounted on a small drone is proposed. The miniaturization was designed by applying the perturbation method based on the λ/4 microstrip antenna and lengthening the current path at the edge of the patch. The miniaturized antenna was fabricatred such that it could be attached to the surface of styrofoam(ε_r=1.06, t=10 mm) having a size of 10 mm × 9 mm × 10 mm (0.05 λ × 0.05 λ × 0.05 λ). The thickness and length of the feeding line and the spacing between short stubs were adjusted for impedance matching. S₁₁ was found to be -18.8 dB at the center frequency of the fabricated antenna, 1.575 GHz. The radiation pattern measurement results show that the maximum gain of E_θ is 1.87 dBi in 0 directions in the xz-plane, and that E_θ is an omnidirectional characteristic with an average gain of -1.7 dBi in the yz-plane. It was found that the antenna can be used as an ultra-small microstrip antenna, which can be mounted on a small dron for GPS, and is capable of preserving a reduction ratio of 98.8% as compared to a λ/2 microstrip patch antenna.