• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.2
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• pp.134-141
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• 2007

A series of experimental work has been conducted to evaluate the capability of microstrip patch antenna system in detecting delamination in fiber reinforced Plastic (FRP) sheet reinforced concrete. For that purpose, a prototype microstrip patch antenna was developed with 15 GHz center frequency and 1 GHz bandwidth. For the comparison, a horn antenna with 15 GHz center frequency and 10 GHz bandwidth was used for the measurements of the same specimens. The laboratory sire specimens have the dimensions of 600 mm (length) $\times$ 600 mm (width) $\times$ 50mm (thickness) with a series of delaminations of 300 mm (length) $\times$ 300mm (width) $\times$ 5, 10, 15 mm (thickness). FRP of 1.5 mm thickness and epoxy of 3 mm thickness were placed on the top of artificially created delamination to represent actual FRP reinforced concrete condition. In all cases, the delamination has deen successfully identified. Also, it was shown that imaging results in microstrip patch antenna were improved by signal processing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.897-903
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• 2002

In this paper, a modified feeding structure for microstrip patch antenna is suggested for improving the performances. The proposed antenna has a gap between the transmission line and the recessed part of the radiating patch which makes a capacitive coupling. It shows higher 511(-l4dB) and lower cross polarization level(-2OdB) compare with the conventional inset ftd patch antenna while having a similar characteristics in another evaluating items. Experimental results are examined and considered to apply to the S-Band application, and the effectiveness has been confirmed by FDTD simulation and measurement simultaneously.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.668-677
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• 1998

This paper is to verify the availability of the finite difference time domain (FDTD) method for the analysis of millimeter wave microstrip patch antenna. Using this method, the size of the microstrip patch antenna resonating at 32.153 GHz is optimized and the input impedance, the voltage standing wave ratio and the radiation pattern are calculated. The resonance frequencies of the microstrip patch antenna are calculated by MOM and FDTD method and then compared with the measured results, showing the difference of 12.27% and 1.27% respectively. Also, the bandwidth of this Ka-band patch antenna is about 8% which is similar to the case of X-band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.96-103
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• 2003

A cavity-backed microstrip patch antenna for a monopulse radar system is designed and fabricated. Also, this antenna is shown to be suitable for the system by analyzing the measured results. Since the azimuthal beamwidth required by this system is quite broad compared to that of a usual microstrip antenna, the width of a microstrip patch is reduced considerably. The decrease of an antenna bandwidth due to the reduced patch width is compensated by increasing the effective substrate thickness. A detection range and a detection probability is calculated from the measured gain at a given angle, and this result shows that the fabricated antenna can be applied well to this monopulse radar system.

• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.634-640
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• 2015

This paper deals with the design of a microstrip line feed toppled T shaped microstrip patch antenna that gives dualband characteristics at 4 GHz and 6.73 GHz respectively. The simulation of proposed antenna geometry has been performed using method of moment based IE3D simulation software. A radial basis function neural network (RBFNN) is used for the estimation of bandwidth for dualband at 4 GHz and 6.73 GHz respectively. In RBFNN model, antenna parameters such as dielectric constant, height of substrate, and width are used as input and bandwidth of first and second band is considered as output of the network. To validate the RBFNN output, an antenna has been physically fabricated on glass epoxy substrate. The fabricated antenna can be utilized in S and C bands applications. RBFNN results are found in close agreement with simulated and experimental results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.83-84
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• 2016

A wideband stacked patch antenna with parasitic elements, rectangular and triangle shaped patches, is proposed. Two different shaped parasitic elements are placed in the above of main rectangular microstrip patch antenna in order to achieve wide bandwidth for 860 MHz band. Coupling between the main patch and parasitic patches is realized by thick air gap. The gap and locations of parasitic patches are found to be the main factor of the wideband impedance matching. The proposed antenna is designed on a ground plane with small size of $119mm{\times}109mm$ for application of compact transceivers. And the impedance bandwidth of the antenna should satisfied CDMA band to the 780MHz~890MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.370-377
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• 2001

This paper proposed an eccentric annular ring microstrip antenna which has an asymmetric slot and a tuning stub for improving bandwidth and size of the circular microstrip patch antenna. The field characteristics of the eccentric annular ring microstrip antenna have been calculated by using the method of FDTD (finite difference time domain). The calculated results showed good agreement with the measured results. As a result of measurement, the antenna size and the bandwidth has been improved to that of 12.2 % and 4.8 % respectively, comparing to circular microstrip patch antenna.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.64-71
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• 2007

In this paper, we have designed and fabricated microstrip antenna of S-band for the wireless LAN and the ISM. It array $2{\times}2$ circular patch antenna elements at plane instead of conventional rectangular patch antenna elements. It optimized to size calculated of single patch antenna. The radiation elements distance is array $0.24{\lambda}$. The fabricated circular patch antenna decreased 8% of size compared to the conventional rectangular patch antenna. In the E-plane, designed circular microstrip patch $2{\times}2$ array antenna gain is 12.7[dBi], half power beam width is $40^{\circ}$ and in the H-plane, antenna gain is 12.1[dBi], half power beam width is $45^{\circ}$. Bandwidth is 250[MHz] (VSWR < 2).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.161-166
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• 2007

In this paper, two 4$\times$4 rectangular patch array antennas operating at 20 GHz are implemented for the satellite communication. The sixteen patch antennas and microstrip feeding line are printed on a single-layered substrate. The design goal is to achieve high directivity and gain by optimizing design parameters through permutations in element spacing. The spacing between the array elements is chosen to be 0.736$\lambda$. Numerical simulation results indicate that the HPBW(Half-Power Beam Width) of the 4$\times$4 patch array antenna is 18.78 degrees in the E-plane and 18.48 degrees in the H-plane with a gain of 17.18 dBi. Numerical simulations of a 4$\times$4 recessed patch array antenna yield a HPBW of 18.71 degrees in the E-plane and 17.82 degrees in the H-plane with a gain of 19.43 dBi.

• Journal of Broadcast Engineering
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• v.2 no.1
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• pp.1-7
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• 1997

In this paper, a microstrip patch antenna was analyzed by using FDTD method. Firstly, the electric field in the microstrip patch antenna was obtained by approximating a Maxwell's equation to a finite difference equation by means of Yee's algorithm. In this case, Mur's 1st approximation and dispersive boundary condition(BBC) were applied to an absorbing boundary condition. We also analyzed a single microstrip patch antenna by using the FDTD method, then calculating the propagative process in the wave of a return loss. Also, as the result that FDTD was applied to 2-array antenna designed to increase the gain of antenna, the measured results was in relatively good accordance with the values calculated by the FDTD method. The calculated impedance, return loss and VSWR were comparatively good. And these results were In relatively good accordance with the measured values.